HVAC School - For Techs, By Techs

Latest Episodes:

How to Predict Air Flow Issues in the Sales Process Nov 21, 2024

Chris Hughes and Steve Rogers from The Energy Conservatory discuss TEC's TrueFlow technology and its crucial role in predicting airflow issues in the sales process, particularly for heat pump retrofits. They explain how the TrueFlow app helps contractors accurately measure both static pressure and airflow in existing systems, enabling them to predict whether proposed equipment changes will work effectively. This is especially vital when considering the growing trend of replacing gas furnaces with heat pumps, as the airflow requirements can differ significantly.

The conversation delves into a detailed example of replacing an 80% efficient 48,000 BTU furnace with a heat pump. They demonstrate how the airflow requirement would nearly double from 652 CFM to 1,200 CFM, potentially causing the static pressure to quadruple due to Fan Law 2 principles. This dramatic increase could lead to significant performance issues if not properly addressed during the system design phase. The experts emphasize that using TrueFlow during the sales process allows contractors to identify potential problems and necessary modifications before installation rather than discovering issues during callbacks.

The discussion also covers the ideal workflow for system assessment and sales, starting with customer comfort evaluation and proper load calculations. It's important to reduce loads through envelope improvements when possible, particularly in cold climates where heat pump retrofits are becoming more common. Proper system sizing often means going smaller rather than larger, contrary to common industry practices, and the worst HVAC systems are often found in expensive custom homes rather than tract housing.

Key Topics Covered:

TrueFlow technology and its role in system forecasting
Fan Law 2 and its impact on static pressure when changing airflow
Heat pump retrofit challenges and considerations
The importance of accurate load calculations
Dual fuel systems as a solution for cold climates
The relationship between airflow and static pressure
Sales process integration of technical measurements
Common issues with oversized equipment
The importance of envelope assessment
Methods for reducing system loads
Proper duct sizing and modification strategies
The role of proper filter sizing and selection
The benefits of flat-rate pricing for duct modifications
Training resources and support available for TrueFlow users

Check out TEC's YouTube channel at https://www.youtube.com/@energyconservatory, and you can visit TEC's website at https://energyconservatory.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

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MCA is 27 and the Breaker is a 50A - Short #219 Nov 19, 2024

In this short podcast episode, Bryan and Mike from DITEK talk about what to do in tricky electrical scenarios, such as when the MCA is 27 and you have a 50A breaker.

When you size an HVAC system for compatibility with voltage monitors, like the DITEK Kool Guard, you need to pay attention to the MCA (minimum circuit ampacity), which should not be confused with MOCP (maximum overcurrent protection or breaker size). As long as the MCA is 40 amps or lower, you can attach the HVAC condenser to the Kool Guard. The KG2 also accepts wire sizes up to 6 AWG.

The Kool Guard is NOT a source of overcurrent protection; it is a voltage monitor rated for carrying current, which means ratings will be in MCA, not MOCP. MOCP is designed to deal with high starting amps and lets users know the maximum allowable current for a circuit so that it can trip properly when that current is exceeded. According to Section 440 of the National Electrical Code (NEC), motors with internal overload protection allow for a difference between the MCA and MOCP. You may find higher MOCPs on inverter-driven systems.

Learn more about DITEK at https://www.diteksurgeprotection.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Deploying Surge Protection & Voltage Monitoring w/ DITEK Nov 14, 2024

Bryan discusses surge protection devices (SPDs) with Mike from DITEK, focusing on practical applications for HVAC contractors and how to provide value to clients. Mike emphasizes that surge protection is essential for modern HVAC systems, particularly given that they are typically the most expensive appliance in a home and increasingly rely on sophisticated electronic components like variable-speed compressors and inverter boards.

The conversation delves into installation best practices, with a detailed discussion of proper wiring techniques for SPDs. Mike explains that surge protectors should be installed in parallel with the circuit, typically at the disconnect, and addresses common concerns about double-tapping lugs and ground connections. He emphasizes the importance of keeping wire lengths as short as possible and provides guidance for installations both with dedicated disconnects and panel-direct connections.

A significant portion of the episode focuses on DITEK's Kool Guard (KG2) product, which represents an evolution in HVAC protection by combining surge protection with voltage monitoring. Mike explains how modern HVAC equipment, particularly inverter-driven systems, is increasingly sensitive to both over-voltage and under-voltage conditions. The Kool Guard monitors voltage on each phase independently and provides visual indication of fault conditions through LED indicators, making it easier for homeowners to identify potential issues without opening electrical enclosures.

Key Topics Covered:

· Why every modern HVAC system needs surge protection

· Installation locations and proper wiring techniques for SPDs

· The difference between line-side and load-side installation

· Ground connection best practices

· How to protect both condensers and air handlers

· The evolution from basic surge protection to voltage monitoring

· The importance of voltage monitoring for modern inverter-driven equipment

· How Kool Guard monitors voltage phase-to-ground vs line-to-line

· Common power quality issues beyond lightning strikes

· How to discuss surge protection with customers

· The limitations of utility-provided surge protection

· The impact of aging power infrastructure on power quality

· The advantages of USA-made surge protection products

· How voltage monitoring prevents damage from brownouts and over-voltage conditions

· The pre-programmed voltage protection ranges in Kool Guard

· Visual indication features for fault conditions

Learn more about DITEK at https://www.diteksurgeprotection.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Pumping vs. Compression - Short #218 Nov 12, 2024

In this short episode, Bryan clears up the confusion behind pumping vs. compression.

Pumping is usually associated with liquid. Liquid, like vapor, is a fluid, but it's a lot denser and is essentially incompressible because the molecules are close together. Liquid volume varies based on temperature and density, but we can't squish the molecules together. That's why compressors with very little axial and radial compliance fail when flooded; they can't compress the liquid. A circulator pump in a hydronic system is an example of a pump that pushes liquid along, but the pressure difference across the pump is minimal compared to that of a compressor; the same is true of liquid vs. vapor CO2.

However, vapor molecules are far apart and can be squished together to take up a smaller volume. That's why vapor can go through compressors, which take a fluid of one volume and apply pressure to shrink it to a smaller volume, raising the temperature in the process. Pneumatics, as opposed to hydraulics, utilize compression to move vapor around in a circuit. Recovery machines need to be able to compress vapor refrigerant and pump liquid into the recovery tank.

Compressors and pumps can either be positive displacement or non-positive displacement systems. A positive displacement system creates a trap and forces a fixed amount of fluid through a system, like a scroll compressor or a circulator pump. Refrigerant volumes may vary because vapor density varies with temperature and pressure (the volume flow is the same, but the mass flow varies). A condensing fan motor, on the other hand, is dynamic and varies the volume of air it moves in response to pressure, as the mechanism relies on velocity and kinetic energy to move air.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Building Tech Confidence w/ Refrigeration Mentor Nov 07, 2024

Trevor Matthews returns to the HVAC School Podcast to discuss building tech confidence and personal growth in the HVAC and refrigeration industry. The conversation explores the transformative power of self-investment, continuous learning, and maintaining a positive mindset. Trevor shares his personal journey from a hesitant technician to a successful business owner, highlighting the importance of pushing beyond comfort zones and embracing continuous improvement.

Some fundamental mindset shifts are necessary for professional development. Trevor candidly discusses his early career struggles, including his initial fear of public speaking and technical challenges. He emphasizes that confidence isn't something that happens overnight but is built through consistent effort, studying, and maintaining a willingness to learn. The key to the growth mindset is to focus on personal progress instead of comparing your achievements to those of others, and it's a perspective that can dramatically impact professional and personal growth.

Self-investment consists of dedicating time to learning, staying physically and mentally healthy, and maintaining a positive attitude, and it can open up unprecedented opportunities. Many technicians have transformed their careers by adopting a growth mindset, continuously seeking knowledge, and being willing to step outside their comfort zones.

Key Topics Covered:

Building professional confidence
The importance of continuous learning
Overcoming fear and self-doubt in technical careers
Strategies for personal and professional growth
Maintaining a positive mindset
Investing in self-improvement
Balancing work, health, and personal development
The power of small, consistent actions
Avoiding comparison with others
Techniques for staying motivated
Recommended resources for personal development

Recommended Resources Mentioned:

Book: "Limitless" by Jim Kwik
Book: "Good to Great" by Jim Collins
Book: "Think and Grow Rich" by Napoleon Hill
Book: "Mastery" by Robert Greene
Podcast: Hidden Brain
Podcast: AC Service Tech

Check out Refrigeration Mentor at https://refrigerationmentor.com/ or email Trevor at trevor@refrigerationmentor.com.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Molecular Transformator - Short #217 Nov 05, 2024

In this short podcast episode, Bryan talks about the CPS Molecular Transformator and what it does.

The Molecular Transformator is a version of a tube-in-shell heat exchanger, which is a method of exchanging heat from one fluid medium to another fluid medium. Tubes containing a fluid pass through a shell containing water or glycol, and there is a heat exchange between that secondary fluid and the fluid being circulated in the tubes. In a Molecular Transformator, the fluid being circulated is recovered refrigerant, and the secondary fluid is water (in a bucket), which absorbs heat from the refrigerant and cools it down to make sure that the refrigerant enters the recovery tank as a liquid.

Refrigerant recovery machines have condensers inside of them, but they are quite small and don't hold a lot of refrigerant by design; many recovery machines use microchannel coils. A lot of the time, the refrigerant leaving a recovery machine is a liquid-vapor mix and too high-temperature; a lot of people run a hose over the tank or put it in a bucket of ice. The "Molecular Transformator" tries to settle the vapor molecules down into a liquid; it transforms the vapor molecules using the same mechanism as a tube-in-shell heat exchanger.

The main issue is that there will be leftover refrigerant in the Molecular Transformator after recovery. However, you can mitigate this problem with ball valves and proper purging. Do so responsibly to avoid venting refrigerant.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Surge Protection Basics w/ DITEK Oct 31, 2024

In this enlightening episode, we sit down with Mike, a 20-year veteran from DITEK, a leading American manufacturer of surge protection devices based in Largo, Florida. The conversation begins with a brief discussion about recent hurricane impacts in the Tampa Bay area, where DITEK maintains its 65,000-square-foot manufacturing facility. Mike shares how the company, despite facing challenging weather conditions, continued its operations and maintained its commitment to American manufacturing.

The bulk of the discussion centers around surge protection technology and its critical importance in protecting HVAC systems and other electronic equipment. Mike provides an excellent analogy, comparing surge protectors to pressure relief valves for electrical systems. He explains how Metal Oxide Varistors (MOVs) work as semiconductors that create low impedance paths to ground when voltage exceeds certain thresholds. The conversation delves into the evolution of MOV technology, particularly the development of thermally protected MOVs that provide enhanced safety features.

The episode also addresses common misconceptions about surge protection, particularly the belief that surge protectors are primarily for lightning protection. Mike explains that while lightning strikes are a concern, especially in areas like Florida, approximately 65% of surges actually originate from within facilities themselves, often from equipment cycling on and off or other power quality issues. He emphasizes the importance of proper installation, particularly regarding ground connections and lead lengths, noting that every six inches of wire length can add about 100 volts to the clamping voltage of the device.

Key Topics Covered:

DITEK's history and commitment to American manufacturing
Basic principles of surge protection and how MOVs work
Evolution of MOV technology and thermal protection features
Difference between transient voltage and temporary overvoltage (TOV)
Importance of proper grounding and lead length in surge protection
Cascading surge protection strategy for comprehensive protection
UL testing standards and voltage protection ratings (VPR)
Common misconceptions about surge protection
Impact of aging electrical infrastructure on power quality
Importance of customer support and ethical business practices
Installation best practices for surge protection devices
Relationship between ground resistance and surge protector performance
Types of surge protective devices (SPD) and their classifications

Learn more about DITEK at https://www.diteksurgeprotection.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Am I Toxic For Caring? - Short #216 Oct 29, 2024

Bryan answers a listener-submitted question: "Am I toxic for caring?" He gives advice on how to maintain professional relationships while still maintaining very high standards of quality for your own work.

Having high standards is great, but it can be frustrating when you perceive coworkers as having lower standards than you. A poor-quality end product is fairly objective, but other ways of judging coworkers' standards are a lot more subjective and may vary by culture, and we end up judging the person rather than the work. While we should care about the objective outcomes of a job, we want to challenge ourselves when we start comparing others' work to our own unfavorably.

Judging others' work isn't inherently bad or "toxic," but it has to be controlled and done in service of something greater. When we confront others or judge their work, we need to make sure it comes from a place of professional pride (rather than personal pride) and personal humility.

As tradespeople, we don't always do the best work, either. In some mission-critical applications, we need to rely on workarounds to get a quick outcome. In those situations, it's a lot more important to be honest about what we're doing and the value we promise. When we find opportunities for our colleagues to do things better, we can offer advice in service of the job and allow the other person to take it or leave it; we don't get to decide that for others. We also have to acknowledge that people have different natural inclinations, and we'd be wise to respect those differences.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

App Based HVAC Learning Oct 24, 2024

Ruchir Shah joins the podcast to share his journey into HVAC education technology and the founding of SkillCat, a comprehensive training platform for skilled trades. As a five-time entrepreneur in educational technology, Ruchir's path to HVAC was influenced by his earlier work studying the BP oil spill and developing training solutions for oil and gas workers. When COVID-19 hit and many skilled workers found themselves displaced, he recognized a broader pattern of declining income for blue-collar workers over the past 50 years, which led to the creation of SkillCat.

The discussion delves into SkillCat's innovative approach to EPA 608 certification, making it more accessible and affordable at just $10 per month. Their platform uses phone-based testing with built-in security measures, achieving a 97-98% pass rate through comprehensive training. This system addresses traditional barriers like high costs, scheduling difficulties, and low pass rates that have historically made it challenging for people to enter the HVAC field.

SkillCat and HVAC School have started a partnership. This collaboration aims to transform HVAC School's extensive content library into structured, accredited courses within the SkillCat platform. The partnership represents a marriage of HVAC School's technical expertise and industry insights with SkillCat's educational technology capabilities, making high-quality HVAC training more accessible and organized for both individual technicians and contracting companies.

Key Topics Covered:

SkillCat's origin story and mission to make trades education more accessible
Revolutionary approach to EPA 608 certification testing and training
Development of simulation-based training across HVAC, plumbing, and electrical trades
Implementation of career pathing and progress tracking for technicians
Importance of applied learning in trades education
Features of SkillCat's apprenticeship program
Integration of on-the-job assessments through the platform
The role of educational technology in addressing the skilled trades shortage
Continuous improvement approach based on user feedback
Affordability and accessibility of trades education through mobile apps

You can learn more about SkillCat by searching for it in the Google Play Store (Android) or App Store (iOS), or you can visit their website at https://www.skillcatapp.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Apps for Doing Proper Loads - Short #215 Oct 22, 2024

In this short Q&A podcast, Bryan answers a listener-submitted question about apps for doing proper loads. Fred specifically asks about apps or charts that can help an HVAC contractor determine the insulation value of a home without assuming numbers or drilling into walls during load calculations.

Load calculations account for all the ways that BTUs can enter or leave a home: conduction, convection, and radiation. Insulation prevents heat transfer via conduction, so it's important to the load calculation process. High-end HVAC design software like Wrightsoft and Kwik Model 3D will have these features built into them (based on the age and location of the home). ASHRAE's handbook also has tables and data with R-values and U-factors to help you out with Manual J load calculations.

RED Calc is an app that allows you to calculate a wall's R-value with measurements, including surface and air temperatures indoors and outdoors. This RED Calc software is available through the U.S. Department of Energy, as is REScheck. The DOE insulation fact sheet is also quite valuable, as are The Engineering Toolbox and materials straight from the insulation manufacturers.

The best way to get a comprehensive load calculation is to have a lot of tribal knowledge about how houses are built in your area, analyze energy bills, and combine tools like RED Calc with building performance tests.

RED Calc is available through the U.S. DOE at https://basc.pnnl.gov/redcalc. REScheck is available at https://www.energycodes.gov/rescheck.

ASHRAE's resources are available at https://ashrae.org/technical-resources.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Jim Bergmann & MQ Update from NCI Summit Oct 17, 2024

Bryan sits down with Jim Bergmann at the NCI Summit in Asheville, North Carolina, to discuss the latest developments in HVAC technology, training, and industry trends.

The discussion delves into the evolution of MeasureQuick 3.0, highlighting the shift back to a more technician-centric approach. Jim explains how they've redesigned the software to put gauges front and center and implemented an AI-driven system to guide technicians through the process step-by-step. This renewed focus on the end-user experience aims to make the product more valuable for technicians and, in turn, more likely to be adopted as part of standard operating procedures in HVAC companies.

Jim and Bryan also explore the importance of understanding HVAC history and fundamentals. They discuss how revisiting old engineering books can provide valuable insights into the core principles of the industry, often explained in more accessible terms than modern textbooks. This approach to learning, combining practical experience with theoretical knowledge, is something both Jim and Bryan advocate for in technician training and development.

The conversation then shifts to the challenges and opportunities in the HVAC industry, particularly in light of the push for electrification and the adoption of heat pump technology. Jim emphasizes the critical need for proper evacuation techniques and moisture removal in systems, especially for cold-climate heat pumps. He stresses the importance of standardized processes and documentation to ensure consistent quality in installations and maintenance.

Topics covered in the podcast:

MeasureQuick 3.0 updates and user interface improvements
The importance of technician-centric product design
Partnerships between MeasureQuick and organizations like NCI
The value of understanding HVAC history and fundamentals
Challenges and opportunities in adopting heat pump technology
The critical importance of proper system evacuation techniques
Standardizing processes for HVAC technicians in the field
The role of technology in attracting younger workers to the HVAC industry
The benefits of attending industry events like the NCI Summit
The ongoing need for collaboration and knowledge sharing in the HVAC community

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - System Won't Dehumidify? - Short #214 Oct 15, 2024

In this short podcast episode, Bryan answers a listener-submitted question about an HVAC system that won't dehumidify. This question was submitted by a homeowner with a Carrier heat pump with an attic air handler that cools but won't dehumidify on the hottest days of summer. One of the past companies that serviced the system added charge, but the problem wasn't resolved.

This case doesn't seem to be a sizing issue, as the insufficient dehumidification is happening on the hottest days. Normally, sizing issues happen during the edge seasons when temperatures aren't as high as in the summer, but the dew points are still high.

Bryan's first recommendation is to use measureQuick to evaluate the delivered capacity and determine the sensible heat ratio (SHR) by comparing sensible BTUs to latent BTUs. High SHRs are associated with less effective dehumidification and more effective sensible BTU removal.

Then, we have to determine that airflow is properly dialed in. Typically, lower fan speeds are associated with better dehumidification; 350 CFM per ton is typical of humid climates. In the case of two-speed or variable-speed equipment, we should verify that it is staging up and down properly.

On the ventilation side, a duct leakage test is recommended. Proper use of exhaust ventilation, like bath fans and kitchen exhaust, is also critical. Structural leakage and MAD-AIR are also worth checking if a company can measure those, though those are premium services that are usually more expensive.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

What Is Up With Blower Amps & Watts w/ Steve Rogers Oct 10, 2024

Bryan Orr and Steve Rogers dive deep into measuring power consumption in HVAC blower motors, particularly focusing on the differences between PSC (Permanent Split Capacitor) and ECM (Electronically Commutated Motor) technologies. The discussion stems from a question raised at an educators' conference about the accuracy of clamp-on meters in measuring blower motor watt draw, as specified in the ACCA Standard 310.

Steve shares insights from extensive testing conducted with different types of motors and power meters. The tests compared PSC motors with constant torque and constant airflow ECM motors across various static pressure conditions. One key finding was that two out of three field-available clamp-on meters tested were capable of accurately measuring true power at levels expected in residential blower motors. However, one meter showed significant inaccuracy at low power levels, highlighting the importance of carefully reviewing meter specifications before use.

The conversation delves into the concept of power factor and its crucial role in understanding the true power consumption of ECM motors. Steve explains that ECM motors often have a low power factor (around 0.6), which can lead to misconceptions about their efficiency if only the current draw is measured. The discussion emphasizes the need for proper measurement techniques, including simultaneous voltage and current readings with the blower door on, to accurately assess motor efficiency.

Key topics covered in the podcast:

Differences between PSC and ECM motor technologies
Importance of power factor in measuring true power consumption
Accuracy of field-available clamp-on meters for power measurement
Impact of static pressure on motor performance and efficiency
Misconceptions about ECM motor efficiency and longevity
Proper measurement techniques for assessing blower motor watt draw
Relationship between duct system design and motor efficiency
Implications of ACCA Standard 310 for HVAC installations
Challenges in comparing constant torque and constant airflow ECM motors
The role of control algorithms in ECM motor performance
Importance of understanding meter specifications for accurate measurements

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Sizing Heat Pumps for Heat Load - Short #213 Oct 08, 2024

In this short Q&A podcast, Bryan answers a listener-submitted question about sizing heat pumps for heat load in heating mode, something that we haven't talked much about in the past due to the greater need for cooling in our market.

In most cases across the country, a heat pump's heating loads will be greater than the cooling loads. There is a greater swing between the desired temperature and the actual temperature in heating mode than in cooling mode (in terms of sensible BTUs). We don't want to oversize for cooling because of its lower efficiency, comfort, and humidity control due to the shorter runtimes. (However, oversizing for cooling loads is far less of an issue in arid climates.)

We don't want to oversize the heat pump to meet the heating load when we'll far exceed the cooling load. However, that's not much of a concern for the opposite scenario in which we oversize for heating to meet the cooling load. We can add auxiliary heat, such as electrical heat or natural gas in dual fuel setups, to help us meet the heating load; we don't have those same options in cooling. Variable-capacity systems can also be beneficial in scenarios where heating and cooling loads are massively different.

Bryan is excited about future opportunities for standby cooling and heating capacity, such as in the case of a heat pump heat recovery chiller system with buffer tanks. In the meantime, we have to design for vastly different heating and cooling loads and may have to oversize for one or the other.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Water Issues - Spidey Sense Oct 03, 2024

This episode of the HVAC School podcast dives deep into the often-overlooked but critical topic of water issues in HVAC systems. Bryan and Bert discuss the various causes of water leaks and condensation problems, and they explain how to prevent them. They emphasize that water damage is not an inevitable part of HVAC systems and that with proper attention to detail and understanding of the underlying causes, most issues can be prevented.

"Spidey Sense" refers to a heightened situational awareness that allows technicians to anticipate and prevent water-related problems. Common water-related problems include drain backups, improper trap depth, and freezing issues, and Bryan and Bert provide practical advice on how to identify and address these problems. The conversation also covers the importance of proper installation techniques, including the correct placement of float switches, insulation of copper lines, and the pitching of secondary drain pans.

Bryan and Bert highlight the need for technicians to think critically about the root causes of water issues rather than relying on quick fixes or common misconceptions. They debunk myths such as thermostats being set too low and causing freezing, and they emphasize the importance of addressing underlying airflow problems. They also discuss the challenges of condensation in humid climates and the importance of setting proper customer expectations.

Key topics covered in the podcast include:

Common causes of water leaks in HVAC systems
The importance of proper drain installation and maintenance
Freezing issues and their real causes
Secondary drain pan installation and common mistakes
The role of static pressure in drainage problems
Condensation issues on outdoor units and in humid climates
The importance of proper insulation for copper lines and drains
Best practices for installing and connecting float switches
Debunking myths about thermostat settings causing freezing
The need for critical thinking and thorough investigation of water issues

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Cultural Diversity - Short #212 Oct 01, 2024

In this short Q&A podcast episode, Bryan answers a listener-submitted question about cultural diversity in the workplace, especially at an HVAC company. He addresses how we can deal with cultural and language differences in a field where communication is so important.

Being open to different demographics of people is great for the industry, especially since we have an aging workforce and need good people in the trade. There are also plenty of opportunities in the trade. However, that doesn't automatically erase the challenges associated with hiring people who don't speak English fluently with English-speaking clients, especially when it comes to money conversations. (However, you can also increase your client base by being able to serve people who speak other languages.)

Our operations can aid these people and help them integrate into the workplace by offering ESL classes as a workplace benefit, encouraging everyone to be clear and concise in their communication, embracing other forms of communication (like sharing photos), and offering scripts or guidelines for communicating with customers.

Cultures vary, and we can't afford to take a mindlessly xenophobic or excessively open approach. We need to acknowledge what's good for the business and uphold standards, but we need to make space for people of different backgrounds to succeed and contribute to the company and industry. It's also great to get to know people who aren't like us and show interest in other cultures, especially when we get to know them and their families.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Aux Lockout & Balance Point w/ Sensi Sep 26, 2024

In this informative episode of the HVAC School podcast, host Bryan Orr sits down with Tom Lorenz to talk about some of the Sensi thermostat features, particularly aux lockout and balance point. Tom leads the traditional and smart thermostat lines at Copeland and has over 25 years of experience in the industry.

The discussion focuses on two key features of heat pump thermostats: auxiliary lockout and balance point. Tom explains that auxiliary lockout is crucial for energy efficiency, as auxiliary heat (whether electric or propane) is typically more expensive than heat pump operation. All Sensi thermostats now include this feature, which can use internet weather data or a physical outdoor sensor to determine when to engage auxiliary heat.

Balance point settings are complex, and there's no one-size-fits-all approach. Factors like heat pump efficiency, home insulation, local climate, and energy costs all play a role in determining the ideal balance point. They emphasize the importance of contractors understanding the specific equipment and secondary heat source when setting up a system for optimal performance and efficiency.

The conversation also touches on Sensi's approach to thermostat design, prioritizing ease of use and essential features over feature bloat. Tom highlights Sensi's commitment to user testing and creating intuitive interfaces for both contractors and homeowners. The podcast concludes with resources for listeners to learn more about Sensi thermostats and advanced HVAC control strategies.

Key topics covered:

Auxiliary lockout feature in heat pump thermostats
Balance point settings and factors affecting them
The importance of understanding equipment specifications for proper setup
Sensi's design philosophy focusing on user experience
Different methods for determining balance point (logic-based, internet weather, outdoor sensor)
Energy Star certification requirements for thermostats
The evolution of thermostat technology from mercury bulbs to smart controls
The Sensi app and its features, including remote sensor integration
The importance of contractor education in proper thermostat setup
Resources for learning more about Sensi thermostats and advanced HVAC controls

Visit Sensi's site at https://sensi.copeland.com/en-us, and learn more about Sensi's contractor branding at https://hvacrschool.com/sensi.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - How to Deploy a Dehum - Short #211 Sep 24, 2024

In this short Q&A podcast episode, Bryan answers Howard's question about how to deploy a dehumidifier (dehum) in a sealed home. He addresses things like location and fresh air requirements in green-grass markets with high dew points.

Before deploying a dehumidifier, you will need to know about the climate, the structure, and the client's complaints, budget, and comfort goals. You need to make sure the HVAC system is properly installed; the most common obstacle to proper dehumidification is oversizing. HVAC systems need a cold coil to pull moisture out of the air, and we need adequate (but not too much) ventilation in the structure before deploying a dehumidifier. Common obstacles include leaky structures, venting exhaust air into the attic, and constantly running exhaust ventilation (like range hoods or bath fans).

Bryan's preferred setup is to have a dedicated dehumidifier just for the sealed attic, though you can make the HVAC do this if you plan it out during the construction phase. If you bring in outdoor air, you should plan to bring it in through the dehumidifier, but that can interfere with attic dehumidification. You can either use two dehumidifiers or use powered dampers to dehumidify either the attic or house at different times.

You can consult the expertise of groups like the HVAC Grapevine and manufacturers like Santa Fe Dehumidifiers. HVAC School also has a range of dehumidifier topics; you can search for videos, podcasts, and tech tips on the topic in the app.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Leak Detection - Spidey Sense Sep 19, 2024

In this episode of the Spidey Sense series, Bryan and Bert dive deep into the art of refrigerant leak detection, sharing their wealth of experience and practical tips for HVAC technicians. They emphasize the importance of using one's senses and observation skills before relying solely on electronic tools, highlighting how this "Spidey Sense" approach is a hallmark of senior-level expertise in the field.

Visual and tactile cues, including warm suction lines, frosted components, and signs of oil, are vital. Different symptoms point to specific kinds of leaks and various scenarios, so you need to understand the behavior of the system.

Bryan and Bert also discuss the strategic application of soap bubbles, electronic leak detectors, and nitrogen for pressurization. Each method has limitations, and you'll need to know when to employ them for maximum effectiveness. When detecting leaks, consider recent home renovations or equipment vibrations that might contribute to leaks.

Topics covered in the podcast include:

Visual and tactile cues for identifying potential refrigerant leaks
The debate on frosted lines as indicators of low refrigerant charge
Proper use of electronic leak detectors and their limitations
Strategic application of soap bubbles in leak detection
The importance of checking common leak locations (e.g., flare fittings, evaporator coils)
Considerations for leak detection in newly installed or recently serviced systems
The role of nitrogen in leak detection for systems with very low refrigerant charge
Estimating the severity of a leak based on system pressure and charge level
The pros and cons of isolation tests for line set leaks
Techniques for detecting very small, slow leaks that might not show up in pressure tests
The potential use of ultrasonic leak detection tools
The importance of thorough inspection and patience in the leak detection process

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Why Didn't You Notice it Last Time? - Short #210 Sep 17, 2024

In this short Q&A podcast episode, Bryan answers Edward's question about how to deal with customers who ask, "Why didn't you notice it last time?"

There isn't an easy answer to that question. The truth is that air conditioning and home health and comfort issues are complicated, and it's entirely possible that an issue simply went unnoticed (or the symptoms simply weren't apparent yet). The HVAC industry doesn't have a standard slate of tests that can give a comprehensive view of everything that's wrong with a system all at once. It's similar to how a doctor can offer a second opinion that differs from the first doctor you saw.

You have to determine whether the customer wants to place blame or solve the problem when they ask, "Why didn't you notice it last time?" Sometimes, we need to dig deeper to find the root of the problem. We can offer advanced diagnostics and be honest about what that will entail (including pricing), though it's natural for customers to be apprehensive about being sold options. However, we don't want to avoid pursuing solutions either.

There are ways to talk about previous sloppy or incomplete work without placing blame on another technician. The immediate problem is what requires attention, not the last person who worked on the system. Ask the customer to state their goals and the results they want to see, and you can forge a path ahead.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Vacuum Questions Answered Sep 12, 2024

In this episode of the HVAC School podcast, host Bryan dives deep into the topic of vacuum in HVAC and refrigeration systems. He addresses two questions from social media about vacuum, expanding them into a comprehensive discussion of best practices, common issues, and techniques for effective vacuum procedures.

Bryan starts by explaining where to ideally locate a vacuum pump when working on a refrigeration system. He emphasizes the importance of pulling from the largest volume locations possible, often at multi-position service valves on the compressor or wherever accessible ports are available. He notes that systems that have been in operation pose unique challenges due to refrigerant dissolved in the oil, which can significantly increase vacuum time.

The podcast then covers the "one hose method" for pulling vacuum, detailing the process of using a single large hose connected to the suction side with the core removed, while placing the micron gauge on the liquid side. Bryan explains how this method can be highly effective for new systems but may take longer for systems that have been in operation. He also discusses the importance of valve quality.

Key topics covered in the podcast include:

Ideal vacuum pump location in refrigeration systems
The "one hose method" for pulling vacuum
Challenges of vacuuming systems that have been in operation
Using heat and nitrogen to improve vacuum efficiency
Importance of quality valves and tools in vacuum procedures
Proper maintenance of vacuum pumps and micron gauges
Dealing with refrigerant dissolved in oil during vacuum
The science behind evaporation at the oil-vapor interface
Tips for speeding up vacuum in difficult conditions
Recommended resources for further learning about vacuum techniques

Get your copy of Review of Vacuum for Service Engineers at TruTech Tools HERE.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Drain Traps & Static - Short #209 Sep 10, 2024

In this short Q&A podcast episode, Bryan answers a question about drain traps and static pressure. This question was sent by Stephen with The Comfort Squad when he noticed an uptick in nuisance calls on retrofit systems that kept having their secondary drain pans filled.

In negatively pressurized systems (i.e., straight-cool or heat pump units, not gas furnaces), air can pull water back into the drain line. The evaporator coil is under negative pressure because the blower is on top of the evaporator coil.

The rule of thumb for trap depth is that it should be greater than or equal to twice the return static pressure (which is why a 1" deep trap is typical for systems with 0.5" return static pressure). However, return static can have some variation, and it's also not a great idea to use the TESP for this measurement because the return static could be greater than the supply. It makes most sense to account for the highest possible return static you will see.

1" is only sufficient if 0.5" return static pressure is the most you will see, so bigger is usually better in all cases. If you can install a 2" or 3" trap, you'll typically have your bases covered without having an excessive trap.

We also wrote a tech tip about this topic: https://hvacrschool.com/drain-trap-depth-and-negative-pressure/

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

How Do You Ramp Up Your Team to Effectively Service and Support CO2 Applications? Sep 05, 2024

In this informative episode, Bryan Orr speaks with Andre Patenaude from Copeland about CO2 refrigeration systems. They dive deep into the unique characteristics and challenges of working with CO2 as a refrigerant, providing valuable insights for HVAC and refrigeration professionals looking to expand their knowledge in this growing field.

Andre explains the reasons behind the increasing adoption of CO2 systems, including regulatory pressures and environmental benefits. He details the peculiarities of CO2 refrigerant, such as its high triple point and lower critical point, which create unique operating conditions not seen in traditional refrigerants. The conversation covers the concept of transcritical operation and how it affects system design and efficiency.

The discussion then shifts to the infrastructure of CO2 systems, focusing on the transcritical booster architecture commonly used in supermarket applications. Andre breaks down the components and operation of these systems, highlighting key differences from traditional setups. He also touches on the latest innovations in compressor technology from Copeland, including new designs specifically engineered for CO2's high-pressure applications.

Key topics covered in the podcast include:

Reasons for adopting CO2 refrigeration systems
Unique properties of CO2 as a refrigerant, including triple point and critical point
Explanation of transcritical operation and its impact on system design
Overview of transcritical booster system architecture
Pressure zones and safety considerations in CO2 systems
Innovations in compressor technology for CO2 applications
High ambient mitigation strategies for improved efficiency
Resources for contractors and technicians to learn about CO2 systems
Upcoming developments in CO2 refrigeration technology
Opportunities for contractors in the growing CO2 refrigeration market

Resources

Tech Tips

Podcast Episodes

Videos

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Condensating Vents - Short #208 Sep 03, 2024

In this short Q&A podcast episode, Bryan answers Kenton's question about how to stop vents from condensating, especially when sealing and insulation don't do the trick.

When approaching a condensation problem, we have to consider the source of moisture and where the condensation is happening. Moisture that builds up on top of the vent comes from attics with a high dew point. (It's not because hot meets cold! Relative humidity and dew point are a lot more important, though hot air is able to hold more moisture.) Warm, moist air with a high dew point hits a colder surface when there is improper sealing and insulation where the duct attaches to the boot.

People often attempt to solve condensation issues by adding insulation, which actually has the opposite effect because it reduces the surface temperature; condensation worsens. Some people also increase attic ventilation, but that may cause pressure imbalances that drive moist air into the conditioned space.

The best way to control attic conditions is to seal and then dehumidify the attic, though it is an expensive and time-consuming measure. Exhaust vents that end in the attic also add moisture to the attic. Sealing vents and other areas where attic air can seep into the space is another best practice, as is deploying a humidity control strategy. Reducing humidity can happen with a dehumidifier and proper sizing so that the HVAC equipment has long runtimes with a cold evaporator coil (achieved with lower system airflow).

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Residential & Rack Startup and Commissioning (Part 2) Aug 29, 2024

In this episode, Bryan and Max discuss commercial supermarket startup and commissioning with comparisons to residential HVAC work. Max, who has transitioned from residential air conditioning to supermarket refrigeration, shares his insights on the unique challenges and requirements of this specialized field.

The conversation begins by emphasizing the critical importance of safety in supermarket refrigeration work. Unlike residential jobs, technicians often work alone in potentially hazardous environments with high-voltage equipment and large quantities of refrigerant. Hearing protection is stressed as a crucial safety measure due to the extremely loud environments in motor rooms.

Max then delves into the complexities of supermarket refrigeration systems, describing the various components involved, including parallel compressor racks, refrigerated cases, and multiple control systems. He highlights the need for adaptability and problem-solving skills, as technicians often encounter unique situations with limited documentation or manufacturer support. The discussion also covers the time-sensitive nature of the work, with many tasks needing to be completed overnight to minimize disruption to store operations.

The podcast explores the multifaceted role of a supermarket refrigeration technician, touching on topics such as equipment decommissioning, pressure testing, electrical verification, and programming of control systems. Max emphasizes the importance of developing a comprehensive process and continuously refining it to improve efficiency and effectiveness in the field.

Key topics covered in the podcast:

Safety considerations in supermarket refrigeration work
Components of commercial refrigeration systems (compressor racks, cases, controls)
Time constraints and overnight work in supermarket settings
Decommissioning old equipment and installing new systems
Pressure testing and leak checking procedures
Electrical verification and three-phase power considerations
Programming and verifying control systems
Defrost cycle setup and verification
Communication protocols and building management systems
Performance audits and client expectations
Low ambient controls and regional differences in system requirements
Leak detection and walk-in cooler maintenance
The importance of developing and refining work processes
Transition from residential HVAC to commercial refrigeration

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - EPR and Pressure Limiting Valves w/ Matthew Taylor Aug 27, 2024

In this episode, Matthew Taylor joins the podcast to dive deep into the world of pressure-limiting valves and regulators used in refrigeration and air conditioning systems. They explore the intricacies of Maximum Operating Pressure (MOP) expansion valves, Evaporator Pressure Regulators (EPR), and Crankcase Pressure Regulators (CPR), discussing their functions, applications, and differences.

The conversation begins with an explanation of MOP expansion valves, which are commonly used in low-temperature refrigeration applications and air conditioning systems. Matthew describes how these valves work by using a vapor-charged thermal element to limit the suction pressure, protecting compressors from operating outside their designed range. They discuss the differences between liquid-filled, vapor-charged, and cross-charged valves, highlighting how each type affects system performance and superheat control.

The discussion then shifts to larger systems and rack refrigeration, where Crankcase Pressure Regulators (CPRs) are preferred over MOP valves. Matthew explains how CPRs control pressure closer to the compressor, allowing for better superheat control in systems with longer piping runs. The conversation concludes with an explanation of Evaporator Pressure Regulators (EPRs), which are used in multi-evaporator systems to maintain specific evaporator temperatures independently of the overall system suction pressure.

Topics covered in the podcast:

· Maximum Operating Pressure (MOP) expansion valves

· Liquid-filled vs. vapor-charged thermal elements

· Cross-charged valves and superheat control

· Applications of MOP valves in small refrigeration systems and air conditioning

· Crankcase Pressure Regulators (CPRs) for larger systems

· Evaporator Pressure Regulators (EPRs) for multi-evaporator setups

· Differences between MOP, CPR, and EPR in pressure control

· Challenges of pressure control in rack refrigeration systems

· Impact of pressure-limiting devices on compressor longevity

· Considerations for technicians when working with different types of systems

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Residential & Rack Startup and Commissioning (Part 1) Aug 22, 2024

In this episode of the HVAC podcast, Bryan and Max Johnson from Kalos discuss the critical role of a startup and commissioning technician in the HVAC industry. Max, who has experience in both residential and commercial HVAC, shares his insights on the importance of understanding the scope of work, equipment specifications, and code requirements.

One of the key responsibilities of a startup and commissioning technician is to prevent any costly issues that may arise during the installation process. This includes identifying and addressing potential problems with ductwork, refrigerant charge, electrical wiring, and airflow. A comprehensive checklist ensures that no crucial steps are overlooked, such as setting up communicating equipment properly, ensuring the correct accessories are installed, and verifying the drain system is functioning correctly.

Proper electrical work is another critical aspect of the startup and commissioning process. Max highlights the importance of using the right connectors and wire sizes to prevent issues like loose connections or overloaded circuits, which can pose fire hazards. Additionally, he stresses the importance of verifying the voltage is within the acceptable range for the equipment, as over-voltage can lead to premature failures.

Airflow is another crucial factor that the startup and commissioning technician must address. Setting the correct airflow before charging the system is essential, as it ensures the equipment operates efficiently and effectively removes the necessary amount of latent heat. He recommends using tools like the TrueFlow grid and DG8 manometer to accurately measure and validate the airflow.

Follow the manufacturer's charging recommendations closely, as each piece of equipment may have unique requirements. Use a comprehensive calculator, such as the one available on the HVAC School website, to determine the proper charge based on factors like line set length and size.

Key Topics Covered:

· Understanding the role and importance of a startup and commissioning technician

· Developing a comprehensive checklist to ensure no critical steps are missed

· Addressing potential issues with ductwork, accessories, and drain systems

· Proper electrical work, including connector selection and voltage verification

· Importance of setting the correct airflow before charging the system

· Following manufacturer guidelines for refrigerant charging

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Stubborn Old Techs - Short #207 Aug 20, 2024

In this short podcast of the Q&A series, Bryan answers a question about "stubborn old techs" (submitted by Luke via Speakpipe).

In several cases, old-school techs are "being positional," which means they feel that they have a piece of turf to protect; they see challenges to the status quo as a threat. They may want to defend the way that they do and have always done things. Many of these people also have insecurities and have dealt with a lot of frustration and disrespect over the years, but they also have a lot to offer. Younger technicians can benefit from listening to these people and their experiences and showing empathy.

Change is difficult, and "unlearning" or "unteaching" is an art. We can approach it by being open-minded and finding the truth behind the original thought that needs to be unlearned, not by being argumentative. Bryan applies these methods all the time when discussing practices like flowing nitrogen while brazing, which was indeed unnecessary when we used mineral oil but is necessary now that we use POE oil.

Speaking with others respectfully is the key; don't speak condescendingly or try to prove them wrong. We all have insecurities and our walls up, and we won't win everyone over, but showing respect and empathy is the key. In the best cases, mutual respect will grow once you prove that you have another person's best interests at heart and that you're not out to get them.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Modulating Compressors w/ Copeland Aug 15, 2024

In this episode, Josh Souders from Copeland joins the HVAC School Podcast to discuss modulating and variable capacity technologies in HVAC systems. Josh provides an in-depth look at the different levels of modulation available in residential HVAC equipment, from traditional fixed-speed systems to two-stage, multi-stage, and true variable-speed compressors.

The conversation covers the benefits of modulating systems, including improved energy efficiency, better comfort, and enhanced humidity control. Josh explains how modulating technologies allow systems to more closely match the actual cooling or heating load of a building, reducing temperature swings and providing more consistent comfort. He also discusses how longer run times with modulating systems can improve dehumidification performance in humid climates.

The interview delves into the technical details of how different modulating technologies work, from two-stage scroll compressors with solenoid valves to inverter-driven variable speed compressors. Josh highlights some of the challenges and considerations when implementing modulating systems, including proper sizing, airflow matching, and control strategies. The discussion also touches on cold climate heat pumps and how variable speed technology enables better performance in colder temperatures.

Key topics covered:

Types of modulating HVAC technologies: fixed-speed, two-stage, multi-stage, variable-speed
Benefits of modulation: energy efficiency, comfort, humidity control
Technical details of how modulating compressors work
Importance of proper system sizing and airflow matching
Cold climate heat pump applications
Energy efficiency ratings and standards (SEER, EER, HSPF)
Federal and local incentives for high-efficiency HVAC systems
Upcoming refrigerant transitions to A2L refrigerants
Industry trends towards increased adoption of modulating technologies

Arm yourself with knowledge from AC & Heating Connect by Copeland at https://www.ac-heatingconnect.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Q&A - Testing Dehumidifiers - Short #206 Aug 13, 2024

In this short podcast episode of the Q&A series, Bryan answers a question about testing dehumidifiers (submitted by Steven via Speakpipe).

Dehumidifiers run air over a cold evaporator coil (to pull moisture out of the air and drain it out) and then reheat it over a condenser coil. The air leaving a dehumidifier is of a higher sensible temperature than the air going in, but there are fewer overall grains of moisture.

To see how well a dehumidifier is working, you will need to know the dehumidifier's rating and have the manufacturer's charts at your disposal. You'll also need to be mindful of barometric pressure and know the basics of using a psychrometric chart or app.

You'll want to monitor the dew point delta (the difference between the dew point of the air going in and the air going out) to determine how well a dehumidifier is doing its job. Entering air conditions will heavily impact a dehumidifier's performance, and power consumption is another important measure of dehumidifier efficiency.

To collect data, you must place one psychrometer at the dehumidifier inlet and one at the outlet; you'll get the dry-bulb and wet-bulb temperatures needed to make a comparative measurement and plot points on the psychrometric chart. You can also measure the condensate output and do the math to determine how much moisture is being removed per hour, but that would hinge on constant operation and consistent entering air conditions.

"Dehumidifier Facts and Troubleshooting" tech tip by Genry Garcia: https://hvacrschool.com/dehumidifier-facts-troubleshooting/

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Improving Changeout Outcomes Aug 08, 2024

In this episode, we dive deep into the world of residential HVAC installations and improving changeout outcomes with Matt, a senior technician and residential install supervisor at Kalos Services. Matt brings a wealth of experience from both the service and installation sides of the business, offering valuable insights into improving installation processes and workmanship.

The conversation highlights the importance of thorough planning and communication in today's HVAC industry. With younger, less experienced technicians entering the field, there's a growing need for detailed instructions and oversight. Matt emphasizes the role of pre-installation videos, photos, and careful site assessments in preventing miscommunications and potential issues during installations.

A significant portion of the discussion focuses on quality control and the impact of workmanship on customer satisfaction. Matt stresses the importance of post-installation photos for peer review, allowing for catching errors and improving overall quality. The conversation also touches on the delicate balance of providing constructive criticism to younger technicians while maintaining positive relationships and fostering a culture of continuous improvement.

Key topics covered in the podcast:

Challenges in residential HVAC installations, including attention to detail and craftsmanship
The importance of thorough planning and communication before installations
Using pre-installation videos and photos to improve clarity for technicians
Post-installation quality control through photo submissions and peer review
Managing younger technicians and providing constructive feedback
The role of customer perception in judging installation quality
Specific technical considerations for the central Florida market, such as condensate management and voltage regulation
The importance of proper system commissioning and documentation
Creating a training culture and career pathing for technicians
Balancing efficiency with thorough quality checks and testing
Adapting to changes in the HVAC workforce and industry practices

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Spidey Sense - Airflow - Short #205 Aug 06, 2024

In this short podcast, Bryan talks about how to pay close attention to airflow issues and use your "spidey sense" when you're doing a visual inspection or commissioning a system. He also covers some causes of common airflow problems and some services and upgrades you can offer to your customers.

The skill of being able to use your senses and notice when something isn't quite right is a valuable one, especially when you're getting ready to set the charge. Not every technician has access to the tools to do a comprehensive airflow assessment, but every tech can use their senses to determine when something is wrong with the system airflow. Keep an ear out for whistling or other strange noises, and watch out for cabinet shaking, which may indicate an airflow problem.

Airflow restrictions are also significant issues. Filter cleanliness (or lack thereof) and improper filter selection are very common causes of airflow issues, including high static pressure drop. Most filters should also not be doubled up (in series). Watch out for furniture blocking vents and registers that are partially (or fully) closed; shutting off registers is NOT a good strategy. Air movement throughout the building is also important, including the presence or absence of returns, open doors, etc., and these things affect MAD-AIR.

Watch out for things like leakage as well, which can be around the platform, in ducts around the equipment, and around vents or recessed lighting.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Preventing Low Voltage Issues Aug 01, 2024

In this episode, Bryan and Bert dive deep into the world of low voltage wiring in HVAC systems. They discuss common mistakes, best practices, and troubleshooting techniques that technicians and contractors should be aware of when dealing with control wiring.

The conversation begins with a focus on mechanical issues, such as running wires in places where they can be damaged and poor splicing techniques. Bryan and Bert emphasize the importance of proper wire stripping, both for the outer jacket of control cables and individual conductors. They share tips on how to avoid damaging wires during installation and stress the significance of planning wire placement, especially behind thermostats.

The discussion then shifts to common miswiring issues, including incorrect terminal connections and misunderstandings about system configurations. They explore the challenges of wiring heat pumps, straight cool systems, and gas furnaces, highlighting the importance of understanding how different thermostats and equipment interact. The hosts also delve into the complexities of dehumidification control wiring and the need to comprehend how various controllers operate.

Bryan and Bert also address communicating systems and offer advice on preventing communication issues. They stress the importance of running new control wiring, considering shielded cable for long runs, and being meticulous about connections.

Topics covered in the podcast:

Proper wire stripping techniques for control cables
Common miswiring issues in HVAC systems
Thermostat wiring and configuration challenges
Dehumidification control wiring complexities
Heat pump vs. straight cool/gas furnace wiring differences
Communicating systems and preventing communication issues
Using shielded cable for long control wire runs
Troubleshooting intermittent low voltage problems
The importance of reading manuals and understanding system configurations
Tips for managing wires behind thermostats and in control panels
Using megameters for testing control wires
Encouragement for technicians dealing with low voltage issues

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

STOP Overthinking! - QA Short #204 Jul 30, 2024

In this short podcast from our Q&A series, Bryan answers a viewer question and implores you to STOP overthinking in the trade! He also shares a parable and some tips to help stop overthinking, especially if you're just starting out in the trade.

In many cases, the simplest assumption is the right one (this is called Occam's Razor). We can always start with the most obvious or simplest possible answer. We can become mindful of our tools, such as by making sure our seals are intact, and we become masters of the obvious.

Perfecting little things (and micro-tasks) can help you become more familiar with the tools you use and the equipment you work on, and you start to develop a bigger-picture understanding of your craft. Cleaning the equipment and organizing your tool bag goes a long way; you can unlock the ability to zoom out and spot mistakes that you otherwise wouldn't have thought of otherwise.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Stewarding Younger Techs Jul 25, 2024

In this podcast episode, Bryan and Dre discuss the challenges and opportunities of stewarding younger techs in the HVAC industry. They explore the growing interest among young people in trades like HVAC, noting a shift away from traditional four-year college paths. The conversation highlights the satisfaction that comes from working with one's hands and the tactile nature of the trade.

The discussion delves into the attributes of younger workers, both positive and challenging. They also address the need to help young technicians understand the seriousness and responsibility of their roles, especially when transitioning from less demanding jobs. The podcast touches on the challenge of helping young workers prioritize their work and manage their time effectively, recognizing the natural tendencies of youth to be more focused on short-term feelings and experiences.

While acknowledging the benefits of tech-savvy workers who can easily access information and use digital tools, they also discuss the need to manage potential distractions from smartphones and social media. The podcast also explores the evolving expectations around work-life balance, on-call schedules, and the importance of clear communication about job demands and responsibilities.

Topics covered in the podcast:

Growing interest in trades among young people
Challenges of managing and mentoring young technicians
The satisfaction of working with one's hands in the HVAC industry
Balancing technology use in the workplace
Adapting to changing work-life balance expectations
Strategies for keeping young technicians engaged and challenged
The importance of building trust and demonstrating care as a manager
Addressing potential boredom and the desire for career progression
The value of mastering skills through repetition and experience
Navigating the rapid promotion of young talent in a growing company
Comparing modern work attitudes with those of previous generations

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Duct Smoke Detector Facts and Wiring - Short #203 Jul 23, 2024

In this short podcast, Bryan answers a listener-submitted question about duct smoke detector facts and wiring. He focuses on Honeywell duct smoke detectors (namely the D4120W), but there are some general best practices that can be applied to most duct smoke detectors.

The power supply may be 24v or 120v AC or DC and may have multiple inputs. You should not break that constant power source. There are also fan shutdown contacts, which may be normally open (alarm condition) or normally closed (non-alarm condition). Supervisory contacts open to indicate a trouble condition to the panel when something in the circuit isn't working properly (NOT an alarm condition). There is often a resistor at the end of the loop, and the alarm panel recognizes a specific resistance. Alarm initiation contacts close and create a shorted condition when there is an alarm condition (the supervisory contacts open if there is a trouble condition).

Smoke detectors in the ducts are different from the ones on ceilings; they usually shut down blowers to prevent the distribution of smoke through the ductwork (and possibly exhaust it to the outside). They are required in duct systems designed for more than (or at least) 2000 CFM per NFPA90 and IMC 606.2.1, though those codes conflict. NFPA90 requires installation in the supply duct, but IMC 606.2.1 requires installation in the return; the AHJ may interpret the code either way. (Smoke detectors in systems >15000 CFM must be in both the return and the supply.)

Overall, remember that different detectors are suitable for different velocities. You will want to keep them downstream of bends for at least 18 inches, test them according to the AHJ, and ensure that they are mounted in the right configuration as recommended by the manufacturer.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Trust the NEW Process: Embracing Evolution in HVAC Technology Jul 18, 2024

In this episode of the HVAC School podcast, host Bryan and guest Jesse Stewart from NAVAC discuss the generational divide in the HVAC industry and the importance of embracing new technologies and processes. They explore the challenges faced by both experienced technicians who may be set in their ways and newcomers to the trade who need proper mentoring.

Jesse emphasizes the importance of respecting traditional methods while making way for new techniques. He discusses how bad habits can be passed down from mentors to apprentices, highlighting the need for continuous learning and adaptation in the rapidly evolving HVAC industry. The conversation touches on the importance of treating apprentices with respect and providing them with educational experiences rather than just menial tasks.

The podcast delves into specific HVAC practices, particularly focusing on evacuation and recovery processes. Jesse explains the significance of using proper tools and techniques, such as valve core removal tools, high-quality vacuum pump oil, and appropriate hoses for different tasks. He debunks common misconceptions about hose sizes and manifold use, providing practical analogies to help listeners understand these concepts.

Topics covered in the podcast include:

The generational gap in the HVAC industry and its impact on training and practices
The importance of continuous learning and adapting to new technologies
Proper mentoring techniques for apprentices
The "beer can cold" method and other outdated practices
The significance of using the right tools for evacuation and recovery processes
The impact of hose diameter on efficiency in evacuation and recovery
The importance of vacuum pump oil integrity
The differences between service, recovery, and evacuation hoses
Debunking the misconception about the impact of connection size on evacuation and recovery speed
The role of manifolds in modern HVAC practices
NAVAC's approach to developing tools based on customer demand while promoting best practices

Check our NAVAC's entire product line at https://navacglobal.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Soft Start & Solar - Short #202 Jul 16, 2024

In this short podcast episode, Bryan dives into soft start & solar technology, which often work together. He also talks about how we can install ductless systems in homes that rely on solar power.

Soft starts are NOT hard starts. Hard starts add more current to the start (auxiliary) winding, which creates a stronger phase shift. Instead, soft starts control the current on the start and run windings and provide just enough of a phase shift to ramp up the motor slowly; it provides a regulated power supply, which means that a slow startup doesn't necessarily cause overheating because there is no locked rotor condition.

We can use soft starts on two-stage compressors but need to make sure the compressor goes up to high speed during the starting sequence. Soft starts "learn" the compressor's cycles, so we need to make sure they are trained to reach the high stage, not the low stage. In systems with multiple compressors, we need to have a separate soft start for each compressor. We don't need to use soft starts on inverter-driven or variable frequency drive (VFD) systems.

Soft starts also make sense in systems that rely on solar technology. Solar technology may be on-grid (where we sell back energy during peak times) or off-grid (where energy is banked). Ductless systems can work with solar energy, but they must be connected to the grid or the bank. Banked solar energy doesn't need to be rectified in the same way that AC power from the electrical company does, which may be advantageous for ductless systems that rely on DC-driven technology.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Make Summer Work for You w/ Matt Bruner Jul 11, 2024

In this episode of the HVAC School podcast, host Bryan Orr welcomes Matt Bruner to discuss the concept of a "summer survival guide" for HVAC professionals. They explore strategies for maintaining work-life balance during the busy summer season and share personal experiences on prioritizing family and personal well-being while managing the demands of the HVAC industry.

The conversation delves into the importance of intentional planning before the summer rush begins. Matt shares how he and his family implement practices like scheduling an end-of-summer vacation, utilizing daycare services, and outsourcing lawn care to create more family time. Bryan emphasizes the need for financial discipline, avoiding impulsive purchases, and instead investing in services that can alleviate stress and create more personal time.

The discussion turns to the challenges of people-pleasing tendencies in the workplace and with clients. Both hosts stress the importance of setting boundaries, learning to say no, and prioritizing one's own family and well-being over excessive work hours or unreasonable client demands. They also touch on the evolution of the HVAC industry, discussing how younger workers are bringing a fresh perspective on work-life balance and how businesses are adapting to these changing expectations.

Key topics covered in the podcast:

Creating a "summer survival guide" for HVAC professionals
Strategies for maintaining work-life balance during peak seasons
Financial planning and discipline to support personal priorities
Setting boundaries with employers and clients
The evolution of work culture in the HVAC industry
Balancing the desire to help customers with personal and family needs
Implementing business practices that reduce stress and improve quality of life
The importance of contentment and avoiding the trap of constant comparison
Adapting service hours and availability to suit personal and family needs
Overcoming the urge to always be available and learning to prioritize personal time

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

How do Inverter Air Conditioners Work? - Short #201 Jul 09, 2024

In this short podcast episode, Bryan answers a listener-submitted question: How do inverter air conditioners work?

Inverter-driven systems have variable capacity to match loads. We can provide cooling or heating BTUs to match the needs of the space without overcompensating or undercompensating and causing temperature swings. Load matching also helps us get better efficiency out of the system. High-humidity climates also benefit from load matching, as equipment doesn't dehumidify well unless it has been running the entire time.

When set up and designed properly, variable frequency drives (VFDs) improve comfort, efficiency, and even dehumidification. You can "overclock" your compressor to get more BTUs out of it without oversizing, particularly when you have high heating loads due to the cold weather.

Inverter-driven equipment takes AC power in, runs it through a rectifier circuit, and turns it into rough power that resembles DC power. The current is then smoothed out and goes through the inverter bridge circuit. Unlike an analog AC wave, we rely on pulse-width modulation (PWM) to simulate three-phase power and control the motor speeds according to a space's needs.

We typically troubleshoot residential inverter-driven equipment by following the manufacturer flowcharts and possibly by communicating with tech support. Commercial VFDs are external to the motors and tend to be a bit more universal rather than manufacturer-specific.

Watch the livestream about VFDs & inverters with Matthew Taylor and Corey Cruz HERE, and you can also watch the livestream about cold climate heat pumps with Ross Trethewey and Russ King HERE.

Learn more about NCI's High-Performance HVAC Summit at https://www.gotosummit.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

How to Size Dehums w/ Tim De Stasio Jul 04, 2024

In this episode of the HVAC School podcast, host Bryan Orr interviews Tim De Stasio, an experienced HVAC practitioner and consultant. Tim shares his journey in the HVAC industry, from his early days in vocational school to running his own contracting business for 12 years. He now focuses on consulting, design, and contractor training, allowing him to pursue his passion for HVAC while sharing his knowledge with others.

The conversation delves deep into the world of dehumidifiers, exploring their importance in modern HVAC systems, especially in humid climates. Tim emphasizes the need for supplementary dehumidification in many homes, particularly during part-load conditions when air conditioning systems may not effectively control humidity. He explains the process of selecting and sizing dehumidifiers, stressing the importance of considering factors such as peak latent load conditions, actual dehumidifier performance under real-world conditions, and static pressure effects on output capacity.

The discussion also covers the critical role of proper envelope sealing and ductwork in managing humidity. Tim advocates for addressing these issues before installing a dehumidifier, highlighting the importance of blower door testing and fixing any leaks. The podcast concludes with insights on dehumidifier control strategies, the limitations of ERVs in humidity control, and the potential risks associated with uncontrolled outdoor air introduction into HVAC systems.

Key topics covered in the podcast:

Tim De Stasio's background and transition to HVAC consulting and training
The importance of supplementary dehumidification in various climates
Selecting and sizing dehumidifiers based on peak latent load and real-world performance
The impact of static pressure on dehumidifier output capacity
The necessity of addressing envelope and ductwork issues before installing dehumidifiers
Strategies for controlling dehumidifiers in conjunction with AC systems
Myths about dehumidification, including misconceptions about variable speed equipment and ERVs
The potential risks of uncontrolled outdoor air introduction and the importance of proper ventilation strategies
Resources for learning more about dehumidification and HVAC best practices

Contact Tim at timdestasiohvac@gmail.com or follow him on LinkedIn HERE. You can also follow David Schurk on LinkedIn HERE.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Teaching Communication Confidence - Short #200 Jul 02, 2024

In this short podcast episode, Bryan shares some strategies for teaching communication confidence, which may come in handy if you have newer techs who feel nervous or struggle to communicate with other people.

The main way to build confidence is to get them to talk in the first place. Scripts and roleplay scenarios during training can help get people used to speaking and give them a reference. Whether we're in sales or not, we have to share information and complete business transactions. Roleplaying those conversations in a controlled, familiar setting allows your more timid team members to put in the reps.

The youngest generation in the workforce tends to be exceptionally uncomfortable talking compared to others; they often prefer to communicate via text. These techs can learn a lot from spending time with customer service representatives (CSRs), especially in difficult situations with upset clients. Then, you can address the non-verbal cues that also play a massive role in in-person communication.

At Kalos, we have developed software that allows people to record voice memos that are then transcribed. We combine this with soft skills training to help build confidence in our team members so that our leaders can understand what their teams are doing. Communication also starts at the top, so leaders must be honest with themselves about their communication skills and how well they regulate emotions and positively convey information. Leaders are also ultimately the ones who are responsible for understanding their team's communication gaps and creating the guidelines.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Using Refrigerant Troubleshooting Charts w/ Joey Henderson Jun 27, 2024

This episode focuses on understanding and effectively utilizing various refrigeration system charts and measurements for troubleshooting and diagnostics. Joey Henderson, an HVAC veteran and trainer, shares his wealth of knowledge and experience on this topic.

Joey starts by discussing the challenges he faced early in his career when trying to make sense of the confusing charts with arrows indicating high, low, high head, low head, etc. He emphasizes the importance of knowing the "supposed to be" values before attempting any measurements or referencing charts. Without this baseline understanding, the measurements become meaningless.

He then delves into specific measurements like subcooling, superheat, evaporator temperature/suction saturation, condenser split, and compressor amperage. For each measurement, Joey explains the ideal range, how to interpret deviations, and how different factors like humidity, airflow, and refrigerant type can affect these values. He also highlights the differences in approaches for fixed metering devices versus TXV/EEV systems.

Topics covered in the podcast:

Understanding refrigeration system charts and their limitations
Importance of knowing "supposed to be" values for meaningful diagnostics
Measuring and interpreting subcooling
Measuring and interpreting superheat
Determining evaporator temperature/suction saturation
Calculating and understanding condenser split
Evaluating compressor amperage
Differences in charging fixed metering devices vs. TXV/EEV systems
Impact of humidity, airflow, and refrigerant type on measurements
Using psychrometers and measuring wet bulb temperatures accurately
Calculating and interpreting Delta T (wet bulb/dry bulb split)
Resources like the Efficient Comfort website and Dick Wirz's RefTech app

Check out some of the resources discussed at https://efficientcomfort.net/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Wiring in Condenser Fan Motors - Short #199 Jun 25, 2024

In this short episode, Bryan talks about wiring in condenser fan motors, including aftermarket motor considerations and the different wire configurations.

When condensing fan motors fail, we need to know what to use to replace them. We often use PSC motors, though in cases when we replace a motor with an ECM, we still need to match the horsepower despite the increased flexibility. The motors we typically keep on our truck are 1/3 or 1/6 HP motors.

Frame size (diameter) and depth also come into play; you may encounter a 42-frame motor or a 48-frame motor. You can't replace an 825 RPM motor with a 1075 RPM one because the poles are different (6-pole vs. 8-pole). Single-phase 208/230v will be the most common motors in residential systems, and the phase and voltage must match. You should also know how to reverse a motor if it is reversible. The bearing type will have some tradeoffs; ball bearings last longer but are louder than sleeve bearings.

3-wire and 4-wire condensing fan motors are essentially the same; the white wire and brown-and-white wire are essentially the same, as there is a jumper inside the motor. You can connect a 4-wire condenser to both sides of the capacitor; in any case, follow the wiring diagram.

When mounting a motor, make sure the wires are strapped properly. Then, remember to unplug the correct weep ports (opposite side of the shaft) to allow condensate to drain out.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Committing to HVACR Education w/ Copeland Jun 22, 2024

This podcast episode focuses on the critical shortage of HVACR technicians and installers across the industry. The hosts discuss the massive gap that exists, with estimates of nearly 200,000 open roles expected in the next few years. They are joined by Lenny Diaddario from Copeland's contractor services department and Chris Harris from the educational nonprofit National Coalition of Certification Centers (NC3).

Lenny and Chris explain the various initiatives Copeland and NC3 have undertaken to help attract more people to the HVACR trades. This includes STEM education outreach to get kids interested from an early age, partnerships with organizations like SkillsUSA and PHCC, virtual reality training tools that allow interactive compressor teardowns, and comprehensive certification curricula developed in collaboration with subject matter experts and instructors.

One major program they highlight is the "train the trainer" events where instructors from trade schools can get certified on the Copeland curriculum over an intensive week. They then take that knowledge back to their schools to teach and certify students as Copeland technicians. The goal is to build a strong foundational workforce of certified HVACR professionals.

Topics covered include:

The severe shortage of HVACR technicians and the need to fill roles
Changing the stigma around vocational education and trade schools
Appeal of trades to younger generations for self-reliance
Copeland's initiatives like STEM days, SkillsUSA, virtual reality trainers
NC3's certification curricula and "train the trainer" instructor events
Copeland's online/mobile training resources like apps and AI assistant
In-person training courses offered ranging from 1 day to multi-day
The long-term vision for socioeconomic impact through a skilled trades workforce

Browse some of Copeland's training opportunities at https://www.copeland.com/en-us/training-support/hvacr-training.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

The Chemistry of Combustion w/ Rachel Kaiser Jun 20, 2024

In this episode of the HVAC School Podcast, Bryan interviews Rachel Kaiser, a chemist with a passion for making science more accessible and understandable, especially when it comes to the topic of combustion. Rachel shares her background of how her family's restaurant business sparked her early interest in chemistry and the science behind mixing ingredients to produce desired results.

Rachel dives deep into explaining the fundamental chemistry behind the combustion process. She breaks down the three key components required for combustion to occur - fuel, oxygen, and a heat source - and how the ideal chemical reaction is represented. However, she emphasizes that in the real world, factors like using natural gas (a mixture of gases) as fuel instead of pure methane and air (also a mixture) as the oxygen source lead to incomplete and imperfect combustion reactions.

The discussion highlights the importance of combustion analysis and monitoring for byproducts like carbon monoxide (CO) and nitrogen oxides (NOx). Rachel stresses that testing is crucial not just for technician safety but to ensure proper combustion for occupants as well. High CO levels, for instance, indicate incomplete combustion and the likely presence of other undesirable compounds.

Topics covered include:

The chemistry definition of combustion/flame
Ideal vs real-world combustion reactions
The three requirements for combustion
Natural gas as a fuel mixture
Air as the oxygen source and mixing considerations
Carbon monoxide and nitrogen oxides as byproducts
The role of combustion analysis
Using visuals/experiments to teach combustion chemistry
Applying chemistry knowledge for troubleshooting

Connect with Rachel on LinkedIn and ask her more about chemistry in HVAC HERE. You can also view her presentation from the 5th Annual HVACR Training Symposium and/or purchase your virtual ticket to all sessions HERE.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Hoses / Types and Applications w/ NAVAC - Short #198 Jun 18, 2024

In this short episode of the HVAC School podcast, Bryan talks about hoses and their various types and applications, particularly focusing on NAVAC hoses.

Charging hoses (NAVAC: NH5 and NH5L) ideally shouldn't be longer than 5-6 feet, as the longer the hose, the more refrigerant it will hold. Manifold gauges also have leak points, so it's usually better to use probes instead of manifolds to help with charging. Charging hoses with ball valves (NH5S and NH5SC) can help you control the flow and are great for recovery. Whenever you use charging hoses, they will have a core depressor on one side only (usually the 45-degree side, if applicable); the right amount should be exposed, and the seal should be in good shape.

Larger-diameter hoses with higher burst pressure are advantageous for recovery (though it's better to have separate hoses for recovery and evacuation). Larger-diameter hoses of a shorter length will allow you to get a higher flow rate, including cases where you have 1/4" connectors (though the F1028 & F1029 Rapid Y connection fittings can help out with those cases where you have 1/4" connectors by giving you the ability to connect two 3/8" hoses); hoses with a diameter of 3/8" are usually the biggest recommended ones for recovery. NAVAC's recovery hoses are the NHR38AA and NHR38AB.

Evacuation hoses are even bigger. Some good evacuation hoses include the NH34AB and NH34AC; they are short 3/4" hoses that are vacuum-rated and quite flexible. NAVAC also has smaller hoses, which tend to look more like recovery hoses. You do not want to use 1/4" hoses and core depressors for evacuation, but they are good for charging.

Check out all of the hoses NAVAC has to offer at https://navacglobal.com/products-by-category/hoses-kits/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Have Fun With CRAC (Computer Room AC) Jun 13, 2024

In this episode of the HVAC School podcast, Bryan interviews Pat Ward, an HVAC technician who specializes in servicing and maintaining computer room air conditioning (CRAC) units for data centers. They dive deep into the unique challenges and setups involved in cooling these critical facilities.

Pat provides an overview of data centers, explaining that they are essentially industrial-scale computer rooms that generate immense amounts of heat from the servers and need precise environmental controls. CRAC units are specialized air conditioning systems designed to maintain the temperature and humidity within tight parameters suitable for electronic equipment.

Unlike typical comfort cooling, CRAC units supply air around 70°F to avoid excessive dehumidification. Humidity control is crucial, often requiring supplemental humidifiers or dehumidifiers. Pat discusses common configurations like air-cooled direct expansion (DX) units as well as chilled water systems with computer room air handlers (CRAHs). Redundancy is a major consideration, with units networked together to stage capacity and provide backup.

The conversation covers many other topics related to data center cooling such as:

Using economizers and free cooling with outdoor air when conditions allow
Potential issues with mildly flammable refrigerants in these applications
Typical maintenance tasks like coil cleaning, filter changes, and refrigerant checks
Accessing and navigating the control systems which often require passwords
Advice for technicians new to working on CRAC units, like studying the equipment layout
The massive scale of large data center installations with arrays of 20+ CRAC units
Causes of overheating and how to avoid them
Growth opportunities in the CRAC niche of HVAC

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Rack Refrigeration Class Part 2 Jun 11, 2024

In Part 2 of the Rack Refrigeration Class at Kalos Services, Matthew Taylor discusses safeties, service, and more. Part 1 focuses more on the basic refrigeration circuit of a rack refrigeration system.

When safeties are piped together, we have to keep in mind that they're a bit more complex than most HVAC refrigeration systems, especially when it comes to the oil side. All of these safeties and their proper installation can be located on the wiring diagrams. Safeties often respond to pressure, both in the refrigerant circuit and the oil circuit, but they may also respond to amperage or temperature.

Each compressor on a rack has its own safety controls, but all compressor safeties should be wired in series. Overloads may measure temperature or amperage and break the circuit if it detects unsafe conditions. We also deploy demand cooling strategies to cool the compressor and help control compression ratios. We can also control capacity with staging strategies. Mechanical controls may be able to communicate with electronic controllers, but these cases are less common in conventional rack systems.

Matthew also covers:

Pop-offs and high-pressure switches
Overloads and misdiagnosed compressor failures
Sentronic oil pressure controls
Mechanical and electronic controls
Adjusting metering devices
Liquid and vapor injection
Subcooling and interstage cooling
Suction filters and when to use them
Service valves, hoses, and depressing Schrader cores for checking charge
Restrictions in the refrigerant circuit
Accumulators
Pressure transducers and troubleshooting
Mechanical and electronic time delays
Bypassing safeties in mission-critical applications
Compressor staging and unloaders

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

What's your summer triage strategy w/ Kevin Hart Jun 07, 2024

This episode dives into an interesting and pragmatic discussion about how HVAC contractors can better balance their workload throughout the year. Kevin from Haven shares insights from observing HVAC businesses across the country and how some are taking a more strategic approach to triaging work.

The main idea is to get systems up and running in the peak summer months when demand is highest, while also collecting data and making notes for more in-depth commissioning, ductwork upgrades, IAQ improvements, etc. that can be tackled in the fall "shoulder season." The hosts discuss the market forces that drive the typical reactive cycle - consumers waiting until systems fail to call for service, companies prioritizing new equipment installs when demand is high to boost revenue, etc.

However, they propose a model where contractors are more proactive about maintenance, communication, and expectation-setting. Install the right-sized equipment over the summer, document issues to revisit later, use data loggers to analyze system performance, and then circle back in fall/winter for comprehensive commissioning when there is more availability. This allows delivering better quality work while smoothing workload across more months.

The episode covers several key points and considerations, including:

Prioritizing load calculation and properly sizing equipment upfront
Deploying IAQ monitors to identify issues like humidity control
Offering full-scope solutions and letting customers decline unneeded services
Shifting technician roles seasonally between installs and commissioning
Developing standard workflows and checklists for each phase
Potential business benefits like retention by providing growth opportunities

Overall, it presents a balanced, practical approach for HVAC businesses to improve quality, reduce stress during peak seasons, and keep technicians engaged through varied work. As Kevin notes, it's a model more contractors could adopt with training and open-sourced best practices.

If you are interested in the workflows discussed in the podcast, you can become a HAVEN pro today at https://pro.haveniaq.com/. You can also email Bryan about summer triage strategies at bryan@hvacrschool.com.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Toasters, Desk Chairs and Socrates w/ Ty Branaman Jun 06, 2024

In this insightful episode of the HVAC School Podcast, Ty Branaman, an exceptional educator and trainer, shares his unique approach to making learning not just effective but also engaging and memorable. He delves into the art of connecting with students, unlocking their curiosity, and fostering a love for learning.

Ty emphasizes the importance of understanding that not all students learn in the same way. He advocates for finding creative ways to capture their attention and spark their interest, whether through hands-on experiments, relatable analogies, or thought-provoking demonstrations. By tapping into students' existing experiences and curiosities, Ty creates an environment where learning becomes an exciting adventure rather than a chore.

One of the key takeaways from the conversation is the power of the Socratic method. Ty encourages educators to ask questions that challenge students' assumptions and encourage them to think critically about the subject matter. By fostering a sense of exploration and discovery, students become active participants in their own learning process, leading to deeper understanding and retention.

Topics Covered:

· Igniting curiosity and making learning engaging

· Utilizing everyday objects and relatable analogies to explain complex concepts

· The Socratic method: Encouraging critical thinking through questioning

· Creating emotional connections through humor, surprise, and joy

· Overcoming frustrations and challenges in the teaching process

· Building a supportive community of educators and learners

· Embracing mistakes and seeing them as opportunities for growth

· Finding creative ways to connect with different learning styles

· The importance of patience and perseverance in the teaching journey

Overall, this podcast episode offers valuable insights for educators, trainers, and anyone passionate about fostering a love for learning. Ty's infectious enthusiasm and creative approach serve as a reminder that education can be a transformative and rewarding experience when approached with empathy, creativity, and a genuine desire to ignite the spark of curiosity in every learner.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Rack Refrigeration Class Part 1 Jun 04, 2024

This podcast episode is Part 1 of a Kalos class on rack refrigeration given by Matthew Taylor. This first segment focuses on the basic refrigerant circuit and oil management of a parallel rack system, common in market refrigeration.

Parallel racks follow the same general process as any other compression refrigeration system. However, they contain multiple compressors on a single rack. These systems have multiple suction lines that tie into one single suction header that feeds into multiple compressors. The suction side of the piping is usually a long distance with varying elevations; risers are vertical stretches of piping that carry oil and refrigerant up and pose a challenge for oil return.

The compressor takes low-pressure vapor on the suction side and turns it into high-pressure vapor on the discharge side. From there, the condenser rejects heat from the refrigerant, which brings the superheated vapor down to saturation temperature and further rejects heat to make the refrigerant fully liquid (subcooled). Metering devices drop the pressure of the refrigerant, and the cases contain evaporators that absorb heat and boil off refrigerant, which travels to the compressors via the suction lines.

Parallel racks come in multiple varieties, but the ones in this podcast are of the direct expansion (DX) variety. Saturation remains a critical principle in these systems: superheat, subcooling, and the pressure-temperature relationship all drive system operation.

Matthew also covers:

Different types of rack refrigeration systems
Customized variations between racks
Looking up case information and reading legends
Oil return and controlling velocity
Mechanical subcooling
Full load amps (FLA) and locked rotor amps (LRA)
Temperature glide: dew point, bubble point, and midpoint
EPR installation
Evaporator efficiency and superheat
Compressor types
Compression ratio and liquid or vapor injection
Oil management components and controls

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

What is Standard 310? w/ Eric Kaiser & Chris Hughes May 30, 2024

Standard 310 is a technical workflow created by ACCA, ResNet, and ANSI for grading the installation of HVAC systems, typically in new home construction. It plays a crucial role in obtaining Energy Star certification, which can qualify homeowners for tax credits under the Inflation Reduction Act. The five steps of Standard 310 are design review, duct leakage test, total system airflow, blower fan watt draw, and refrigerant charge verification.

In this podcast episode, host Bryan Orr is joined by guests Chris Hughes and Eric Kaiser to discuss Standard 310 and its implications for HVAC contractors.

The standard aims to ensure that HVAC systems are installed correctly and operate as designed. The process involves a third-party HERS rater conducting various tests and measurements, which contractors need to be prepared for. Proper duct sealing, airflow settings, and refrigerant charging are critical for passing the assessments.

One of the challenging aspects highlighted is the refrigerant charge verification step. The standard requires either non-invasive testing (which has temperature limitations) or weigh-in verification with geotagged photos. Chris Hughes suggests manufacturers could develop more consistent commissioning protocols to streamline this process.

Topics covered in the podcast:

Overview of Standard 310 and its five steps
Importance for Energy Star certification and tax credits
Role of HERS raters and HVAC contractors
Duct leakage testing and proper sealing
Airflow measurement methods
Blower fan watt draw challenges
Refrigerant charge verification options
Need for consistent commissioning protocols
Coordination and documentation required
Future improvements to the standard

Q&A - Kitchen Exhaust and Makeup Air - Short #197 May 28, 2024

In this short Q&A podcast episode, Bryan answers Gunther's question about kitchen exhaust and makeup air. Gunther asked if there were any studies that showed that makeup air should come very close to the hood to avoid infiltration. He also asked how to educate others who push back against the idea, particularly in kitchen exhaust systems of around 600 CFM.

Commercial facilities, especially restaurants, bring in makeup air to balance out the air being exhausted. There are costs associated with makeup air, but there are plenty of valid reasons to add it to residential structures. Being able to control the makeup air allows us to control where we bring air in from (especially when it comes to drawing in humid air or dirty attic air from gaps and cracks, particularly in vented attics).

Open-combustion appliances in the building envelope are also prone to backdrafting if the structure is under negative pressure. The structure is also more likely to have its dryer vents experience leaks under negative pressure.

The International Residential Code (IRC) (section M1503.6.2) requires makeup air when you have an exhaust system >400 CFM. The Florida Residential Code (section M1503.4) requires kitchen exhaust systems exceeding 400 CFM to have makeup air at approximately the same rate as the exhaust rate. Furthermore, the Florida Mechanical Code (section 505.2) specifies that kitchen exhaust systems exceeding 400 CFM must have makeup air to balance the air pressure and ensure proper ventilation.

Duct Leaks - Measuring, Preventing & Repairing w/ Sam Myers May 23, 2024

This episode featured Bryan Orr interviewing Sam Myers, the building science consultant at Retrotec. Retrotec manufactures products like blower doors and duct testers for measuring air tightness and leakage in buildings.

Sam discussed his role at Retrotec, which involves training contractors on using their tools properly, product design, software testing, presenting at conferences, and running trade show booths. He talked about the demanding travel schedule this requires but also the rewards of educating the industry.

The main topic was duct leakage testing - why it's important, how it's done, interpreting the results, and investigating and fixing duct leaks when problems are found. Sam explained that while a duct leakage test provides a number, that number alone doesn't indicate if the leakage is acceptable or problematic. However, it points technicians in the right direction for further investigating issues like comfort problems, indoor air quality concerns, or high energy bills.

He provided tips on using tools like smoke tests and thermal cameras to visually identify leaks, checking common leak areas like connections and return duct penetrations, and the value of testing before and after making repairs to verify the work. Sam also discussed using low-cost manometers for other tests, like checking room pressure imbalances caused by duct leaks.

Topics covered included:

Sam's role and work at Retrotec
The importance of duct leakage testing
How duct leakage tests are performed
Interpreting duct leakage test results
Common duct leak sources like connections and return penetrations
Methods for pinpointing and verifying duct leaks
Using manometers for other diagnostic tests
Tips for contractors getting started with duct testing

Learn more about Retrotec's resources at https://retrotec.com/.

Q&A - RTU Tips - Short #196 May 21, 2024

In this short Q&A podcast episode, Bryan answers Jeremy's question about checking the charge on rooftop units, and he gives some RTU tips.

Rooftop units often come in sets, so you can use a thermal camera to look at all of the RTUs and compare them. A thermal imaging camera may even show you where subcooling begins in the condenser, which can be a useful diagnostic hack. Try to avoid hooking up gauges each time you check the charge on a rooftop; RTUs have a fixed factory charge, and losses from your gauges can add up over time. Your senses will also come in handy; check for odd sights, sounds, and smells.

Checking suction pressure and superheat is less risky and imperfect, but it'll give you some diagnostic data. You can also check discharge temperatures to check for signs of compressor overheating (remember: 225 stay alive).

Here are some tips for RTUs:

Get familiar with the service manual and wiring diagrams; these items will help you with the job and help you build on your knowledge of RTUs in general.
Make sure you have all of your materials at the ready, including extra screws.
Make sure you have access to the BAS system, if necessary.
Safety is critical on rooftop units, especially when it comes to ladders, lockout/tagout, and ensuring that you have safe access to the unit (this burden is often on the client).
Pay attention to specialized equipment, including ERVs and economizers.
Be mindful of curb installation, transformer taps, and phase monitoring, as those items may not be set up properly.
Build up a basic working knowledge of variable frequency drives or VFDs (or know where to find information about them; THIS livestream is a good start),
Keep systems clean to prevent overheating.
Prevent oil logging whenever you have to replace a compressor.

Practical Loads, Ducts and Sales w/ Brynn Cooksey May 16, 2024

This episode features an insightful conversation with Brynn Cooksey, an experienced HVAC contractor and trainer from Southeast Michigan. Brynn shares his expertise in conducting proper load calculations, sizing the equipment correctly, improving duct design, and addressing common issues contractors face.

Brynn emphasizes the importance of performing accurate load calculations, especially in older housing stock where equipment is frequently oversized by 50% or more. He discusses how oversized equipment leads to short cycling, poor efficiency, and increased utility costs for homeowners. His approach involves educating customers by involving them in the measurement process and using metrics like "duct deficiency" to demonstrate the inefficiencies of their current systems.

The discussion then shifts to heat pumps and the unique challenges of implementing them in cold climates like Michigan. Brynn advocates for a "dual fuel" approach, utilizing heat pumps for efficiency while supplementing with gas heat during extremely cold temperatures. He stresses the necessity of a tight, well-insulated thermal envelope and proper duct design to ensure optimal heat pump performance.

Topics covered include:

Conducting blower door tests for accurate load calculations
Downsizing equipment and solving duct issues in retrofit applications
The "duct deficiency" metric for demonstrating system inefficiencies
Aeroseal duct sealing: benefits, limitations, and proper application
Identifying and addressing cracked heat exchangers due to airflow issues
Training sales teams on a hands-on, educational sales process
The importance of building science education for contractors
Overcoming hesitancy in trusting load calculation results

Brynn encourages contractors to embrace building science principles, trust the load calculation process, and focus on system design rather than simply swapping out equipment. By proving these methods to themselves, contractors can transform their businesses and deliver true value to customers through improved comfort, efficiency, and cost savings.

Learn more about HVAC U and its course offerings at https://www.hvactrain.com/.

Q&A - Starting an Internal Training Program - Short #195 May 14, 2024

In this short Q&A episode, Bryan answers podcast listener Cooper's question about starting an internal training program. Eugene Silberstein has been on the podcast before to offer his perspective on this topic, which you can listen to HERE.

Bryan recommends a combination approach: instructor-led, hands-on, and self-paced learning, all deployed together. Hands-on learning often gets missed, and we can give inexperienced techs experience with some basic troubleshooting tasks or breaking down and reassembling things. The Socratic method can also be employed here; the instructor can ask their trainees questions instead of the other way around. When the instructor is the one who asks the questions, they allow their trainees to be wrong, learn from their mistakes, and make their own connections to the fundamentals.

Learning plans and curriculums are great for giving trainees a structure, but they need to be reinforced with the hands-on component in this trade. When determining what to teach, try to focus on what's most important in your market—the first area of effectiveness—and then understand how to reinforce it. The continuous growth mindset is also critical; the apprenticeship phase is never truly over, and the instructor needs to be able to improve their program over time without letting the idea of unattainable perfection discourage them from giving their training.

You may also read our tech tip about setting up an internal training program and our recent SkillCat guide if you want to deploy training in your business. The ESCO All Access Subscription Bundle for the HVACR Learning Network is another excellent resource.

Bryan Orr - Humility in Thought Leadership May 09, 2024

This podcast episode is Bryan Orr's presentation at the 6th Annual HVACR Training Symposium: "Humility in Thought Leadership." Bryan reflects on his own journey as a trades educator, business owner, husband, and father, sharing personal anecdotes and insights that resonate with anyone in a position of influence.

Bryan begins by acknowledging the challenge of maintaining humility in the face of success and recognition. He emphasizes the need to continually shift our focus from a mindset of "deserving" to one of "serving" others. By embracing humility, we not only become more effective leaders but also create an environment where those around us can grow and thrive.

Throughout the episode, Bryan encourages listeners to embrace vulnerability and be open to feedback from those who care about them. He stresses the importance of surrounding oneself with people who are willing to hold you accountable and challenge you when necessary. This accountability, he argues, is crucial for personal growth and maintaining a grounded perspective.

Here are some of the key topics covered in the symposium presentation:

The importance of empathy and understanding others' perspectives
The distinction between personal humility and professional pride
The dangers of ego and how it can disconnect us from reality
The role of introspection in fostering humility and self-awareness
The impact of how we process memories on our perception of reality
The need to listen to those actively working in the field and remain connected to practical realities
The value of being open to constructive criticism and admitting when we're wrong
The joy of seeing others grow beyond us and the importance of letting go of the need for control

Q&A - Tech to Service Manager Tips - Short #194 May 07, 2024

This short podcast is a Q&A based on a question submitted to us by Andy Holt. Bryan gives some tips on how to go from service tech to service manager. Service managers may have better pay, but they also have different sources of stress than service technicians, and not all service tech skills will translate well to management.

Service techs and service managers have completely different skill sets, and they have to be able to gain satisfaction from different sources. Service techs are satisfied by solving problems, and they get immediate dopamine hits whenever they use their brains and hands to fix someone's AC. Service managers have to find satisfaction in big wins for their team.

Service managers have to manage processes and procedures around customer service; they are involved with customer service representatives and dispatchers. They also handle the most difficult clients and situations, so they need to be able to resolve conflict and stay calm in tense situations. Good service managers also learn to share wins with their teams and speak publicly so that they can inspire and motivate their teams.

Service managers also manage finances, review reports, and send emails, so they need the skills necessary to do that, including writing skills (or technology to assist with writing skills). Leadership roles also require you to represent the policies and procedures of your organization, regardless of how you feel about them. These requirements may put a strain on interpersonal relationships.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

LIVE From the ACCA Conference 2024 May 02, 2024

This episode was recorded live on location at the 2024 ACCA conference in Orlando. Bryan starts by interviewing Marissa, a co-founder of Conduit Tech, a software company providing load calculation and sales tools for HVAC contractors.

Marissa shares insights into what it takes for contractors to successfully adopt new technology in their businesses. She emphasizes the importance of having support at multiple levels of the company, a willingness to thoroughly learn the new software, and providing feedback to the developers. Marissa stresses that Conduit actively seeks input from contractors to continue improving their product's workflow integration. Learn more about Conduit Tech at https://getconduit.com/.

In the second segment, Bryan talks to Martin Hoover, the incoming chair of ACCA (Air Conditioning Contractors of America). Martin discusses the value ACCA provides through training, advocacy, and facilitating peer group interactions. He highlights how ACCA conferences allow contractors to learn from industry leaders and gain valuable perspectives in the hallways between sessions.

The episode covers a range of topics relevant to HVAC contractors, including:

Adopting new technology and providing productive feedback to software developers
Assessing whether a new product will truly transform your workflow based on customer testimonials
The benefits of joining ACCA, such as training, advocacy, and peer networking opportunities
Challenges facing the industry, like labor shortages and rising costs
The importance of understanding your financials and pricing for future costs
Preparing for the transition to A2L refrigerants and associated changes

Whether you're a contractor looking to improve your business or a technician striving for success, this episode offers valuable insights from industry experts on leveraging resources, adopting new tools, and positioning yourself for the future of HVAC.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Positive Productive Client Communication Apr 30, 2024

In this insightful podcast episode, the host delves into the crucial aspects of positive and productive client communication, drawing from his extensive experience in the residential air conditioning industry. He emphasizes the importance of setting the right tone, bringing energy, building trust, and adapting to different customer personalities when interacting with clients.

The host highlights the key elements of positive communication, such as maintaining a consistently upbeat and enthusiastic demeanor, while also being mindful of the client's preferences. He stresses the importance of active listening, to truly understand the customer's needs and concerns, rather than simply waiting for your turn to speak. The host also touches on the challenges of dealing with difficult customers, such as those who are overly focused on price or technical details, and provides strategies for navigating these situations with patience and professionalism.

The discussion then shifts to the productive side of client communication, emphasizing the importance of being clear, precise, and solution-oriented. The host delves into the pitfalls of being a "yes-man" and making promises that are difficult to follow through on, and instead encourages a more assertive and responsible approach. He emphasizes the need to take ownership of one's words and actions, ensuring that any commitments made to the client are followed through with diligence and care.

The podcast also touches on the significance of situational awareness, wherein the host encourages technicians and salespeople to adapt their communication style based on the client's background and personality. Whether it's an aerospace engineer, a computer programmer, or a contractor, the host provides insights into how to tailor your approach to best serve each individual client.

Key Topics Covered:

Positive communication: Setting the tone, bringing energy, building trust, and adapting to customer personalities
Productive communication: Importance of being clear, precise, and solution-oriented
Avoiding the "yes-man" trap and taking responsibility for one's words and actions
Situational awareness: Adapting communication style based on client background and personality
Dealing with difficult customers and navigating challenging conversations
The value of honesty and truthfulness in client interactions
Importance of initial conversations and following up on commitments made to clients
Balancing empathy and professionalism when addressing clients' personal issues or concerns

By addressing these critical aspects of client communication, the podcast provides invaluable insights for professionals in the HVAC industry and beyond, highlighting the key strategies for fostering positive and productive relationships with customers.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Condensate Drains Install & Service Apr 25, 2024

Roman Baugh, Matthew Condron, and Luke Peterson discuss the importance of proper condensate drain installation and maintenance, particularly in commercial applications. The conversation begins with the hosts examining the typical drain configurations seen in different regional markets, highlighting the significant variations in practices across the country.

Sizing and configuration of condensate drains can have a significant impact on system performance, especially in high-static pressure systems. He emphasizes that the "one-size-fits-all" approach of using a 2-inch trap is often insufficient, as the static pressure within the system can overcome the trap's ability to prevent air from being sucked into the drain line. The hosts discuss the chart Roman presents, which provides guidance on selecting the appropriate trap depth based on the static pressure of the system.

The discussion then delves into the challenges associated with maintaining condensate drains, including the buildup of debris and the potential for double traps or airlock issues. The hosts share their experiences and best practices for cleaning and troubleshooting drain lines, with a particular focus on the importance of understanding the system's airflow and static pressure characteristics.

The conversation also touches on the use of condensate pumps, with the hosts expressing mixed opinions on their effectiveness and the potential for issues, particularly in high-humidity environments. The importance of proper insulation and support for drain lines is also highlighted, as sagging or improper installation can lead to further problems over time.

Key Topics Covered:

Typical drain configurations in different regional markets
The impact of static pressure on condensate drain performance
Proper trap sizing and depth based on system static pressure
Challenges with drain line maintenance and troubleshooting
The use of condensate pumps and their potential drawbacks
Importance of proper insulation and support for drain lines
Strategies for cleaning and maintaining condensate drains
Relationship between airflow, static pressure, and drain issues
Redundant protection methods, such as secondary drain pans and switches
Techniques for identifying and addressing air turbulence issues

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

EEV Types - Short #193 Apr 23, 2024

In this short podcast episode, Bryan explains electronic expansion valve (EEV) types. EEVs perform the same function as TXVs, but they operate electronically, not mechanically.

The EEV makes sure that the evaporator is full of the right amount of refrigerant at saturation; it doesn't just affect evaporator pressure. We don't want high superheat (due to inefficiency), and we don't want zero superheat (due to the risk of compressor failure).

EEVs commonly have a stepper motor with a set of discrete settings depending on how many rotations the motor has made. It can be fully open or fully closed, and the number of rotations can set the valve at any value between fully open and fully closed; it's open or closed by a specific percentage. Instead of a bulb and external equalizer, a pressure transducer and temperature sensor report to the controller and give the controller the data it needs to open or close the EEV to maintain a specific superheat.

Pulse-width modulation (PWM) allows an EEV to open and close rapidly. Unlike a stepper motor, PWM solenoids make an EEV stay fully open or fully closed for a specific percentage of time. It receives pressure information from a pressure transducer and temperature information from a thermistor or thermocouple.

As with a TXV, you would look at superheat and pressures to make sure the EEVs are operating correctly.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Heat Pump COP and Low Temp Lock Out Apr 18, 2024

This episode of the HVAC School Live Stream covers the key concepts around heat pump efficiency and understanding the coefficient of performance (COP). Eric Kaiser from TruTech Tools and Jim Fultz from White-Rodgers provide valuable insights into how heat pumps operate and how to optimize their performance, especially in colder weather conditions.

The discussion begins by exploring the COP of heat pumps and how it compares to the efficiency of electric resistance heat. A COP above 1 means the heat pump is delivering more heat for the same amount of energy input compared to electric resistance heat. Many homeowners mistakenly believe they should switch to emergency heat once the outdoor temperature drops, thinking the heat pump is no longer efficient. However, even at very low outdoor temperatures, a well-designed heat pump can still operate with a COP above 1, making it a more cost-effective heating option than emergency heat.

The conversation then delves into the concept of the thermal balance point, which is the outdoor temperature at which the heat pump can no longer meet the heating load of the home. The guests discuss how to calculate this balance point and how to set up controls to optimize the use of the heat pump and any supplemental heating sources, such as electric resistance heat or a gas furnace in a dual-fuel system. They emphasize the importance of proper air distribution and avoiding blowing cold air directly on the occupants, which can be a common complaint with heat pumps.

Key Topics Covered:

Coefficient of Performance (COP) and how it compares to electric resistance heat
Efficiency of heat pumps at low outdoor temperatures
Thermal balance point and how to calculate it
Optimizing control settings to balance heat pump and auxiliary heat usage
Importance of proper air distribution and avoiding blowing cold air directly on occupants
Considerations for dual-fuel systems with both a heat pump and a gas furnace
Best practices for programming thermostats and control systems to ensure optimal performance and comfort

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Motor Protection Types - Short #192 Apr 16, 2024

In this short podcast episode, Bryan talks about motor protection types, including overloads.

The most common overload we see in residential HVAC is a built-in thermal overload, which is usually a bimetallic disk that flexes in response to heat (such as from a locked condition, electrical problem, or simply running hot) and opens the circuit. The two metals have different expansion and contraction rates, which causes the flexing; they will return to their original position once the motor cools down. In some cases, these can fail when they open and close too often; they are not designed for switching duty. Many circuit breakers have a similar thermal design and may be prone to nuisance tripping in the summer.

A lot of commercial motors rely on external overloads; some are even built into the electrical box rather than the compressor. These external magnetic overloads are often integrated into the contactor, which turns the motor on and off; this type of contactor is called a starter. These starters may have adjustable overload settings based on current, not just temperature (which may also respond to nuisance sources of heat and require a cooldown period). Some circuit breakers also trip magnetically and are less likely to be affected by temperature.

Thermistor-based overloads usually consist of a PTC (positive temperature coefficient) resistor; as temperature goes up, resistance goes up, which can take a motor winding out of the circuit. NTCs are in separate parallel circuits with relays; as the resistance decreases, it pulls in a coil that opens the circuit.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Expansion Valves - What Does and Doesn't Matter? Apr 11, 2024

This podcast features a lively discussion on expansion valves, particularly thermostatic expansion valves (TXVs or TEVs), with a panel of expert guests - Corey Cruz (a market refrigeration tech), Matthew Taylor (head of refrigeration service at Kalos), and Joe Shearer (with Precision Air Conditioning).

The conversation kicks off by busting some common myths surrounding expansion valves. The guests agree that minutiae like the precise clocking (rotational orientation) of the sensing bulb or whether it's mounted horizontally or vertically tend to be overemphasized. The key is ensuring good thermal contact between the bulb and refrigerant line.

They dive into the operating principles of an expansion valve, explaining how it's essentially a balanced system of forces between the inlet (liquid) pressure, the outlet (suction) pressure, the pressure in the sensing bulb corresponding to superheat, and the adjustable spring force. Getting the superheat dialed in properly is crucial for efficient system operation.

The experts share valuable insights on best practices like avoiding heat damage during brazing, using the right valve for the application, not adjusting the valve unnecessarily, allowing stable operation before making adjustments, and considerations like external equalizers. Real-world examples and demonstrations with failed valve components illustrate the importance of proper installation and maintenance.

Topics covered include:

Common expansion valve myths and overemphasized factors
How an expansion valve works and the balanced forces involved
Superheat, hunting, and minimum stable superheat
Recommended bulb insulation practices for different applications
Proper bulb mounting, clamping techniques, and thermal contact
When and how to adjust the valve (or not)
Effects of plugged external equalizers and pressure drops
Selecting the right valve size and type (bleed vs hard shutoff)
Common installation errors like reverse flow direction
Troubleshooting tips for various systems and scenarios
Importance of airflow, load conditions, and other system factors

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Q&A - How to Learn Superheat & Subcooling - Short #191 Apr 09, 2024

In this short podcast episode, Bryan answers an audience member's question and explains how to learn superheat & subcooling, two fundamental aspects of the HVAC/R trade. You can submit questions of your own at https://www.speakpipe.com/hvacschool.

Saturation is when a substance is in the liquid and vapor state in the same place. Eugene Silberstein likes to help us envision it by encouraging us to think of a horizon line on the ocean; anything below it is fully liquid (subcooled, what a submarine would travel through), and anything above it is a vapor (superheated, which a flying superhero would travel through).

Superheat and subcooling can tell you a bit about how the HVAC system's main components are operating. High superheat indicates that there's more vapor in the evaporator, and you're not getting as much efficiency out of your evaporator as you probably could. High subcooling indicates that you're stacking more liquid refrigerant in the condenser, which can be good for efficiency but may also reduce the area of the condenser dedicated to condensing the refrigerant.

Superheat and subcooling are NOT just there to help you set the charge; they can tell you a lot about a system and its components.

Ty Branaman has a great webpage about superheat, subcooling, and saturation at https://www.love2hvac.com/saturation-superheat-subcooling. You can also visit his YouTube channel at https://www.youtube.com/@love2hvac.

Craig Migliaccio (AC Service Tech) also has an excellent book on the topic, which you can learn more about at https://www.acservicetech.com/ac-book. You can also visit his YouTube channel at https://www.youtube.com/@acservicetechchannel.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Focus of Your Goals w/ Refrigeration Mentor Mar 28, 2024

In this episode of the HVAC School Podcast, Bryan Orr and Trevor Matthews delve into the importance of setting goals, focusing on them, and taking actionable steps to achieve them. They emphasize that goal-setting is crucial for personal and professional growth and that it requires introspection, prioritization, and sacrifice.

Trevor shares his experience of setting a goal to buy his first house and how writing down the specifics, such as the number of bedrooms and bathrooms, helped him achieve that goal within a few years. He stresses the need to start small, with easily achievable goals, and then gradually build up to larger, more ambitious ones.

Bryan and Trevor also discuss the importance of finding your "why" – the deeper motivation behind your goals – as it provides the drive and determination to stay focused and overcome obstacles. They suggest techniques like the "five levels of why" and creating vision boards to help clarify and visualize your goals.

Here are some key topics covered in the podcast:

· The importance of assessing what you truly want and setting clear goals

· Techniques for finding your "why" and staying motivated

· Prioritizing tasks and managing distractions to maintain focus

· Setting short-term and long-term goals, both personal and professional

· The power of small wins and positive reinforcement

· Investing in yourself and taking ownership of your career growth

· Managing expectations and aligning your goals with your employer's

· Overcoming the mindset of waiting for the "right" time to start

· Practical strategies like scheduling, time-blocking, and budgeting to achieve financial goals

Overall, the podcast encourages listeners to take control of their lives, continuously learn and grow, and make consistent progress toward their goals, no matter how small the steps may seem.

Check out Trevor's Refrigeration Mentor program at https://refrigerationmentor.com/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

When to Switch to Emergency Heat? - Short #190 Mar 26, 2024

In this short podcast episode, Bryan talks about when to switch to emergency heat. He talks about coefficient of performance (COP) and how it's a deciding factor when to run emergency heat, which is when a system ONLY runs the backup heat; it doesn't use it as supplementary heat.

When we have a heat pump with backup electric heat, we shouldn't ever rely just on emergency heat; we want the heat pump to run. Electric heat is just designed to supplement the heat pump's heating because it's inefficient. Hybrid or dual-fuel systems can use gas or hydronic fuel-based heat, and they work well on their own (such as if the heat pump is broken). You can't usually run the fuel-based emergency heat at the same time as your heat pump, so it makes sense to run just the emergency heat if it is fuel-based.

The thermal balance point is the point at which the heat pump can no longer keep up with the heating load by itself; the temperature in the space will start to drop, but the heat pump will still produce heat. The thermal balance point can give us a clue about client comfort, not efficiency. COP is a measure of efficiency, and an electric heater has a COP of 1. A heat pump with a COP above 1 saves energy (compared to using just electric heat). COP is the heat delivered in BTUs divided by the energy supplied; it's a ratio.

You can read the "Good COP - Bad COP" tech tip at https://hvacrschool.com/good-cop-bad-cop/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Manual J in 15 Minutes? Mar 21, 2024

Shelby Breger, co-founder of Conduit Tech, joins Bryan Orr on the HVAC School Podcast to discuss her company's innovative lidar-enabled design and sales software tool for HVAC contractors.

Conduit Tech's software utilizes lidar sensors in iPads and iPhones to scan homes and create 3D models and 2D floor plans. It overlays load calculations factoring in property data, orientation, cooling/heating degree days, and building materials. This allows contractors to perform detailed load calculations on-site in just 15 minutes or less while engaging homeowners visually.

Breger explains that the core goal is to empower contractors to deliver better-designed systems more efficiently while enhancing the customer experience. Homeowners get to see the level of work and customization involved, building appreciation for the contractor's services. The visuals help communicate potential comfort issues and how the proposed solution uniquely addresses their home's needs.

Breger emphasizes that Conduit Tech is focused on solving fundamental industry pain points identified through continuous feedback from their contractor user base. The software has evolved to provide more flexibility to adapt to the realities of home visits. New features like augmented reality equipment visualization further enhance the customer engagement capabilities.

Topics covered include:

How Conduit Tech's lidar scanning and modeling works
Using the software for room-by-room or whole home load calculations
Integrating data sources like property records, ASHRAE design conditions, etc.
Aligning with ACCA Manual J methodologies and certifications
Improving load calculation accuracy through real-world monitoring
Leveraging technology to streamline processes across sales, design, and installation
The value proposition for contractors and homeowners
Roadmap for adding features based on user feedback
How contractors can get started with Conduit Tech's software

Contractors interested in trying out Conduit Tech can visit https://www.getconduit.com/, or they can email shelby@getconduit.com or info@getconduit.com to learn more and schedule a demo.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Combustion Venting Categories - Short #189 Mar 19, 2024

In this short podcast episode, Bryan talks about the four different combustion venting categories for gas appliances as set by ASHRAE and where you'll see them. He also shares some notes about pressurization.

These categories deal with the pressurization and temperature ranges of the vents. Category 1 venting is used for old-school open-combustion gas furnaces; they have high flue gas temperatures and are considered low or mid-efficiency furnaces. This venting category is not positively pressurized, and it has a single-wall flue and operates more like chimneys, as the appliance is usually under negative pressure; a draft is created and draws the flue gas out. It's non-condensing, negative-pressure venting.

Category 2 venting is not common anymore; they operate with negative pressure in the vent, and condensation is still likely.

Category 3 venting is non-condensing positive-pressure venting. These are more common in older through-the-wall appliances.

Category 4 venting is condensing, positive-pressure venting for high-efficiency or condensing gas appliances with lower-temperature flues and sealed combustion. PVC is the most common venting material for these furnaces. We can recover some energy from the condensation process.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

The Gift of Security and Learning w/ Jennifer Manzo Mar 14, 2024

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Jennifer Manzo, founder of HVA-Chicks Coalition. Jennifer shares her unique background as a longtime teacher and homeschooler who stumbled into the HVAC trade while researching vocational options for her homeschooling students.

They discuss the inspiration behind HVA-Chicks, a free training coalition offering technical, career, and personal support to women in HVAC. This includes customized training plans, connecting members with childcare assistance, legal support for discrimination issues, job search help, and more. Jennifer also manages a free 24/7 tech support phone line with several experienced volunteers. She explains why she dedicates endless hours to serving others in the industry at no cost - to provide the help and community she wished for when first starting out.

Jennifer actively works to build women up by first offering them psychological safety and security. When women feel unconditionally cared for, they gain the internal strength and courage needed to push past obstacles in this male-dominated field.

Key topics covered:

· Jennifer's journey from teaching to HVAC

· Lifelong learning

· Overview of HVA-Chicks Coalition offerings

· Managing a free 24/7 tech support phone line

· Motivations for serving the industry with no payment

· Providing psychological safety/security for women technicians

You can learn more about the great resources HVA-Chicks has to offer at https://hvachicks.com/, visit Skillcat to check out the blog where Jennifer writes, and find Jennifer on social media as Hvachicks Jennifer. You may contact Jennifer by her public email at jennifer@skillcatapp.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Belt Talk - Short #188 Mar 12, 2024

In this short podcast episode, Bryan dives into some belt talk, including some bits about pulleys and sheaves. He also shares some belt tensioning tips for your next commercial HVAC job.

Belts are less common than they used to be, but we find them in ventilation fans, RTUs, and AHUs. Squealing belts indicate slippage, which indicates fan inefficiency and energy losses. Belts transmit energy from the motor (pulley) to the fan or blower wheel being driven by it. Motor mounts may be adjustable, but there will be a means of adjusting the tension of the belt. Before we change or replace a belt, we need to make sure the belt is properly aligned (centers should have the proper distance and pitch). Common sense and good observation skills will be your best tools.

Adjustable sheaves shouldn't be touched when you're changing the belt; the adjustment of the sheave is for airflow based on the RPM of the fan motor, not tensioning or setting amperage. We set belt tension by tensioning with a specific tool: a belt tensioner. Belts should be as loose as possible without slipping, but belts will loosen a bit over time and with everyday use, and they may slip eventually. Wear on the pulleys may also cause belts to slip.

Cogged belts, also called notch belts, may bend more easily, last longer, and be more efficient due to reduced resistance (compared to non-cogged belts). Belt efficiency can also be affected by alignment and tightness (being too tight).

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Using the Roomulator w/ Chris Hughes Mar 07, 2024

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Chris Hughes of The Energy Conservatory (TEC) about using the Roomulator card and DG-8 manometer for room pressurization testing.

Chris provides background on how he came up with the idea for the Roomulator. He wanted an easy way for technicians to properly size passive returns to relieve pressure imbalances between bedrooms and the main body of a home. The Roomulator card enables technicians to quickly measure door undercuts and size transfer ducts, grilles, etc., to reduce room pressures to 3 Pascals or less per ENERGY STAR guidelines. When paired with the DG-8 micromanometer, the system provides precision room pressurization measurement.

They discuss reasons why excessive room pressures can cause comfort, efficiency, and indoor air quality issues. Removing positive pressure helps reduce airflow through leaks in exterior walls, lighting fixtures, etc. Chris also talks about how the Roomulator is an affordable “gateway tool” for technicians to get started with building science and air pressure dynamics. DG-8 allows technicians to perform several other tests beyond room pressurization as they advance their skills.

Key topics covered:

TrueFlow grid and DG-8 manometer
Origins and purpose of the Roomulator card
The step-by-step process for using Roomulator and DG-8
Impacts of room pressurization on comfort, efficiency, IAQ
Role as an introductory tool for building science testing
The collaboration of NCI and TEC

You can learn more about the Roomulator and purchase a few at https://store.energyconservatory.com/roomulator.html.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Primary & Secondary Air in Combustion - Short #187 Mar 05, 2024

In this short podcast, Bryan dives into a gas heating topic: primary & secondary air in combustion.

Primary air is the air and oxygen content that enters the furnace BEFORE combustion. In older furnaces, prior to induced combustion, air was drawn in through the front. These older furnaces had adjustable shutters that we could modify to bring in more or less primary air based on our combustion analysis readings. We could also use flame color to get an idea of the CO content (yellow tips on the flames indicate higher carbon monoxide content).

In systems like those, air is drawn in via Bernoulli's principle; there are areas of low pressure around areas of high velocity. There is pressure associated with the natural gas, which draws air into the burner. Nowadays, we have induced draft systems (not to be confused with power-vented systems) to draw air in at a fixed rate for more consistent combustion. These inducer fan blowers are necessary for the more complicated heat exchangers we see in more recent furnaces. Secondary air is the air after combustion.

We only want to adjust primary air if we have the correct gas pressure, so we will want to make sure we perform combustion analysis. We can also clock the meter (if applicable), but you will not always have a meter, and you will want it to be informed by combustion analysis.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Learning Outside the Box (Live Rebroadcast) Feb 29, 2024

This podcast episode is a live rebroadcast of a livestream with Craig Migliaccio (AC Service Tech) and Ty Branaman (love2hvac). It focuses on different types of learning and how to make the most out of learning experiences.

The hosts discuss the differences between random learning, goal-driven learning, and forced learning. Random learning involves casually exposing yourself to new information without a specific end goal. It can be useful for sparking curiosity. Goal-driven learning is focused on achieving mastery of a particular topic in order to solve a problem or accomplish something concrete. This type of learning requires effort but tends to be the most effective. Forced learning is when someone else compels you to learn certain material, often for compliance reasons; this type lacks intrinsic motivation.

They emphasize surrounding yourself with a community of curious people who can provide encouragement, accountability, and inspiration. Events like the HVACR Symposium and AHR Expo facilitate making these connections. Building personal relationships and enjoying the humanity in the field sustains interest and passion.

Key topics covered:

The role of books, podcasts, conferences, and interpersonal interactions in learning
Differences between propositional, procedural, perspectival, and participatory knowledge
Using the Socratic teaching method of asking leading questions
Understanding real-world applications of Ohm's Law
Distinctions between random, goal-driven, and forced learning
Finding joy and connection through education and community
Networking with people across the industry at trade events

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Making Family Business Work w/ Leilani Orr Feb 22, 2024

In this podcast episode, Bryan has an enjoyable conversation with his wife Leilani about navigating family relationships while building a business. They discuss the challenges and benefits of mixing family and work, setting boundaries, and maintaining perspective.

Bryan starts by admitting he felt intimidated to have Leilani on the podcast before, joking about her “big muscles and dominating presence.” Leilani jokes back, saying Bryan seems less intimidated now that they’ve been together so long. They then dive into the topic of starting their family business, Kalos, back in 2005.

Leilani remembers feeling excited but also some “pain” around Bryan turning down a big raise to go out on his own instead. She was impressed he felt so confident to leave the security of a paycheck, which made her believe Kalos would succeed. However, as a young couple they were already not making much money, so the pay cut hurt.

Other topics they discuss:

Holding morning meetings with employees in their small home when Kalos was just starting out
The awkwardness Leilani felt sometimes hearing family members complain about each other or the business
How they’ve generally had good boundaries between family issues and personal relationships
Funny stories about occasionally discussing business at improper times around non-family friends
Taking on jobs outside Bryan's wheelhouse (like painting) in the early days out of necessity
The importance of being willing to do work others may see as "below them" to make a small business succeed
How Bryan easily gets bored doing repetitive tasks, and prefers to delegate
Leilani's appreciation that Bryan respects her contributions to the family and doesn't compete with her for time
The need for humility and perspective when running a family business

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Heat Pump Basics in Plain Language Feb 15, 2024

In this solo podcast, Bryan provides an introduction to heat pumps, explaining the basics of how they work and key considerations in a way that is easy for anyone to understand. He starts by reviewing some core HVAC principles - that heat moves from higher temperatures to lower temperatures, the three main methods of heat transfer, and the concept that temperature is really just a measure of molecular movement.

He then explains that a heat pump works by taking heat from a place that doesn't matter, like the outdoors, and putting it where it is wanted, like inside a home. This is the opposite of an air conditioner. The only difference in the actual equipment is the addition of a reversing valve to change the direction of refrigerant flow and a defrost control board. He talks about the need to defrost the outdoor coil when ice builds up and what happens in that mode.

Some key challenges and design considerations he covers when using heat pumps include: dealing with defrost and where the melt water will go, keeping the outdoor unit free of snow, supplemental heating systems for when the unit can't keep up, increased electrical load, and factors like the climate zone, home efficiency, electricity prices, and infrastructure. He emphasizes that with good design focused around heat pumps, they can work efficiently even in cold climates.

Topics covered:

· Basics of heat transfer

· How heat pumps move heat

· Reversing valve and defrost board

· Defrost challenges

· Supplemental heat

· Sizing and design considerations

· Use in cold climates

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Women in HVAC (Live Rebroadcast) Feb 08, 2024

This podcast brought together several women working in the HVAC industry to discuss their experiences and offer advice. The conversation focused on the positives of working in HVAC as a woman, the importance of community, and the resources available.

The women talked extensively about how welcoming and supportive the HVAC community, and particularly HVAC men, have been towards them. Several got into the industry because of their husbands' work. They agreed the perception that it's difficult for women to break into HVAC does not match their largely positive realities. The biggest challenges they identified related more to things like clothing and bathroom options rather than discrimination or harassment.

Advice offered for companies looking to hire more women focused not on targeting women specifically, which could cause resentment, but on ensuring good benefits, upholding anti-discrimination standards, and facilitating connections with other women in the industry. Several mentioned the value of groups like Women in HVAC and the Society of Women Engineers for networking and support. Attending conferences to connect with the HVAC community was also repeatedly recommended.

Overall, the positive tone revealed that with the right connections, women can thrive in HVAC careers. All expressed passion for their work and eagerness to encourage more women to explore the industry.

Topics covered:

Getting into HVAC
Challenges for women in HVAC
Advice for attracting/supporting women
Importance of community
Groups like Women in HVAC
Conferences/events

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

History of AWG - Short #186 Feb 06, 2024

In this short podcast, Bryan explains the history of AWG, or American wire gauge, which is the sizing system we use for conductors in the United States.

Wires weren't standardized before the 18th century (1700s). As fencing, telegraph, and electrical wires started coming out, there was a need for a standardized system. In England, a standardized system called the Birmingham wire gauge (BWG) was developed in the 1800s. The American Telegraph Company developed the American equivalent, the AWG, shortly afterward. These systems standardized wiring diameters, and the AWG's wire sizes get bigger as they get lower (including NOT wires, which are noted by the number 0 on the gauge, like 2/0).

The AWG scale is a logarithmic scale, meaning that the wire sizes don't vary by a fixed amount; there is a 20% variation between diameter sizes. Our brains are programmed to understand proportionality (i.e., logarithmic values and patterns) better than discrete values. This sizing system based on a logarithmic scale makes it easier for us to observe differences between the diameters.

The metric system for wire sizing is NOT logarithmic; there is a root-10 progression between sizes; this standard is called IEC 60228.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

A2L Update With Chemours Live from AHR Feb 01, 2024

Don Gillis and Dr. Chuck Allgood from Chemours join the show to discuss their new easy as "1,2,3" branding around the A2L refrigerants R454A, R454B, and R454C. They explain that A2Ls are not actually flammable like hydrocarbons; they are just mildly combustible with much lower burning velocity and energy than propane or butane. The key is that A2L refrigerants can only be used in equipment specifically designed and tested for them.

They outline several equipment changes, like the inclusion of sensors that detect leaks and mitigate risks by shutting down systems. Service ports will be red to denote flammability. Refrigerant cylinders will move away from colors and instead use red bands/markings to signal A2L, along with left-handed threads and updated pressure relief valves. Best practices like nitrogen purging, confined space protocols, and leak repairs will become outright requirements. Tools like recovery machines and leak detectors will need A2L ratings, but most from the past 2 years likely already have them.

In closing, the guests emphasize that A2Ls contain no propane or hydrocarbons and cannot be retrofitted into existing A1 equipment. Contractors should get trained, adopt the solutions coming, and not fear progress. But they should spread the word that A2Ls are not simply being dropped into old equipment.

Topics Covered:

Differences between A2Ls and flammable refrigerants
Required safety features in A2L equipment
Changes to refrigerant cylinders
Updating tools and practices for A2Ls
Retrofitting existing systems with A2Ls (not allowed)
Spreading proper understanding about A2Ls

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

What is DX? - Short #185 Jan 30, 2024

In this short podcast episode, Bryan tackles the following question: What is DX?

In short, DX stands for "direct expansion," which means that you cool the end product via the refrigeration cycle. We blow air over an evaporator coil, which allows the refrigerant to take up heat from the air and directly expand. Chillers, boilers, and chilled water systems are NOT direct expansion systems; they use a secondary fluid like water or glycol to move the heat throughout the structure, not an evaporator to take up heat directly. They also have heat exchangers to move heat from the refrigerant to the secondary fluid.

DX systems tend to be smaller, and chillers and boilers tend to be larger. Chillers are advantageous in cases where we're working with toxic or flammable refrigerants or large refrigerant charges; we can keep the refrigerant charge away from the structure and space or product(s) needing to be heated or cooled.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Vacuum and Recovery in an A2L World with Jesse Stewart Jan 24, 2024

In this podcast, Bryan Orr interviews Jesse Stewart from NAVAC about A2L refrigerants and compatible tools and safety procedures.

They discuss how NAVAC has a full line of A2L-compatible tools for evacuation and recovery, including the new NR7 and upgraded models of the NRDDF and NRDD. Jesse explains key features that make tools A2L compatible, like DC motors, sparkless designs, insulated electrical terminations, soft power switches, and fans. He notes that NAVAC has been designing tools this way in preparation for wider A2L adoption.

The conversation covers some evolving questions around A2L systems, like requirements for strike plates to protect line sets and whether existing line sets can still be used. They agree that ongoing questions need to be directed to organizations like ASHRAE to get definitive guidance. Overall, Jesse emphasizes that best practices are now required, not just recommended, when working with A2Ls. He details several examples, like nitrogen purging while brazing, the "10-foot rule" for checking potential ignition sources, and proper confined space protocols.

Topics covered:

NAVAC's line of A2L-compatible tools
Key safety features for A2L tools
Evolving regulations and best practices around A2L systems
Using nitrogen while brazing
The "10 foot rule" before A2L installations
Working in confined spaces with A2Ls
Adapting outdated practices to meet new safety needs

Explore NAVAC's A2L-compatible tools at https://navacglobal.com/a2l-compatible-tools/ or general products at https://navacglobal.com/. You can also ask the experts for help by emailing training@navacglobal.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Safe Chemicals are Good Chemicals w/ Mike Pastorello Jan 24, 2024

This podcast covers refrigeration technologies' growth and focus on providing safe, high-performing chemicals for HVAC technicians without hazardous ingredients.

Mike Pastorello discusses the 2017 rebranding that gave their products a more modern, cohesive look. He also talks about bringing on new marketing talent like Ashley and Becca to amp up refrigeration technologies' social media presence and connect more directly with end users. Throughout, Mike emphasizes enabling the marketing experts to drive strategy rather than micromanaging.

Regarding products, Mike highlights their priority of keeping technicians safe while effectively doing their jobs. He mentions constantly improving formulas to eliminate skin burns, bad odors, and other issues with traditional chemicals. Bryan shares an example from his contracting company where lax safety practices led to an emergency room visit and realigned his team's commitment to using safer alternatives like Viper products.

They also overview popular refrigeration technologies offerings like Nylog thread sealant and the Venom Packs compact container system. Mike states the Venom Packs will avoid upcoming taxes on traditional gallon jugs. Bryan praises the durable, flexible packaging and smaller nozzle.

Bullet points:

2017 rebrand and modernizing refrigeration technologies' visual identity
Bringing on new marketing talent to expand social media reach
Empowering new hires to take the lead rather than micromanaging
Keeping technicians safe while effectively doing their jobs
Continually improving chemical formulas to reduce hazards
An emergency room visit underscoring the need for safety focus
Overview of Nylog refrigerant thread sealant
Benefits of the durable and flexible Venom Packs

Check out all Refrigeration Technologies products at https://www.refrigtech.com/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

How Better Truck Stock Makes the Trade Better w/ Jim Fultz Jan 24, 2024

This live podcast from AHR Expo 2024 discusses the costs of truck rolls for HVAC technicians and how technicians and companies can reduce those costs. Jim and Bryan highlight that every time a tech has to go to the supply house to get parts, the company loses money in potential service calls that could have been completed. They emphasize stocking trucks properly so that technicians can complete repairs efficiently without leaving jobsites.

Jim talks about the White Rogers 50M56X8-43 universal control board, which auto-configures itself to different furnace models. He explains how it simplifies installations and troubleshooting, allowing techs to solve problems faster. Bryan adds that having universal parts encourages techs to thoroughly diagnose issues before replacing components. They also discuss the display showing flame current in microamps, which helps techs benchmark flame rod cleanliness over time.

Later, Jim stresses the importance of techs understanding all the individual components in heating systems rather than seeing units as intimidating beasts with complex wiring. Bryan shares how new controls with better interfaces and indicators help guide techs to increase their skills and knowledge. They agree that improvements allowing faster on-site repairs provide a better, more rewarding experience for both techs and customers.

Throughout, Jim and Bryan sprinkle in jokes, stories, and food references while emphasizing the overarching goal of giving techs what they need to enjoy their work and provide the best service possible.

Topics covered:

Costs of truck rolls and supply house trips
Stocking trucks for same-day repairs
New universal control simplifying installations
Diagnosing issues thoroughly before replacing parts
Display showing useful flame current readings
Understanding all components in heating systems
Improved interfaces and indicators enhancing skills
Faster on-site repairs benefiting techs and customers
Loving your work and helping people

Check out Copeland's trusted products and brands at https://copeland.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

The VCRT Redesigned + More w/ Fieldpiece Jan 24, 2024

In this podcast, Bryan chats with Tony Gonzalez of Fieldpiece about their latest innovations for service tools, including the redesigned VCRT, as well as the training resources they offer.

They start off discussing Fieldpiece's philosophy of developing solutions for technicians' real pain points, not just making products. Understanding workflows and obstacles lets them design better tools. Tony then reveals their new line of valve core removal tools aimed at faster, easier access to system ports. Features include integrated ball valves to isolate gauges, sight glasses to confirm capture of the core, and improved ergonomics for gripping.

Next they touch on Fieldpiece University, their free online learning platform for HVAC best practices. It contains individual courses as well as guided "training tracks" on full applications like combustion analysis. With quality content being critical, Tony aims to continue expanding their offerings this year.

They also briefly discuss A2L refrigerants - while tool compatibility questions persist in the field, most quality equipment made in recent years carries approvals. Technicians mainly need to verify the manufacturer's guidance and adhere to existing best practices.

Key topics:

New valve core removal tools
Enhanced sight glass and isolation
Continual improvement of Fieldpiece University
Clarifying tools and A2Ls

The overarching theme is providing solutions - both through innovative tools and readily accessible education for the industry. You can learn more about Fieldpiece at https://www.fieldpiece.com/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Absolute vs. Gauge Pressure (Micron Gauge vs. Manometer) - Short #184 Jan 23, 2024

In this short podcast episode, Bryan covers the differences between absolute and gauge pressure, as well as measuring pressure with a micron gauge or a manometer.

Compression ratio deals with absolute suction and absolute discharge pressures. Absolute pressure requires us to add atmospheric pressure to the gauge pressure. We usually measure gauge pressure in pounds per square inch (PSI). PSIG is the gauge pressure (zeroed to atmospheric pressure), and PSIA is the gauge pressure plus the atmospheric pressure (usually around 14.7 PSI).

When we measure vacuum pressure, we have "negative pressure" with respect to the atmosphere. We're not measuring less than zero pressure; we are in a positively pressurized environment, but the pressure is negative relative to the atmosphere (not absolutely). We use microns to measure deep vacuums; they are tiny pressure units equivalent to a millionth of a meter of mercury column. Since microns measure absolute pressure, they always dip below atmospheric pressure and approach 0 (but never reach it because we're not in a perfect vacuum). We don't have to zero the micron gauge because it automatically measures with respect to zero.

Manometers measure pressure differentials; they measure pressure in reference to something else, whether that's the room around you (whatever you've zeroed it to) or another point on the system (measured at the other port). In any case, we're not referencing 0 PSIA. Many manometers may pick up readings in the inches of water column scale, and some even measure very small scales like Pascals.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Is Dual Fuel the Answer? w/ Tom Buescher Jan 18, 2024

In this HVAC School podcast, Bryan and Tom Buescher with Copeland discuss dual-fuel heat pump systems as an intermediate step towards more sustainable heating solutions.

They talk about the overall goal of reducing greenhouse gas emissions from residential heating and cooling, which accounts for over half of home energy use. While heat pumps can provide higher efficiency, simply switching everyone to electric isn’t realistic in the short term. Factors like grid capacity, infrastructure, and consumer comfort have to be considered.

Dual fuel systems allow for a hybrid approach - utilizing heat pumps to provide the bulk of heating, with gas heating as a backup for the coldest stretches. This arrangement allows more heat pumps to be adopted now while still ensuring warmth and meeting consumer expectations. It bridges the gap during this transitional period as grids adapt to more renewable generation.

Key topics covered:

Tom’s industry background
The role of location - dual-fuel makes the most sense in northern climates zones 3-5 currently
Electrical factors - service capacity, indoor air temp, wiring
Existing home challenges - ductwork, insulation
Staged operation of dual fuel systems
Role of hybrid approaches during transitions
New universal controls and thermostats enabling these dual-fuel setups

Overall, Bryan and Tom have a nuanced discussion about creating real progress incrementally, meeting consumer needs alongside policy goals. Considering both environmental and practical perspectives is key.

Visit Copeland’s website at https://www.copeland.com/en-us and Sensi at https://sensi.copeland.com/en-us. You can also watch our new install video featuring the Sensi Touch 2 at https://hvacrschool.com/videos/sensi-touch-2-install/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

NTC, PTC and Thermocouples - Short #183 Jan 16, 2024

In this short podcast episode, Bryan dives into NTC, PTC, and thermocouples. NTC and PTC are two types of thermistors, and all three tools are used to sense temperature.

Thermistors are resistors that change their resistance based on a change in temperature. They must be powered, and the resistance changes the amperage. You can test a thermistor with an ohmmeter at a fixed temperature. The best temperature for testing is the thermistor's rated temperature, typically 77 degrees Fahrenheit.

NTC thermistors are negative temperature coefficient thermistors; as the temperature decreases, the resistance increases, and vice versa. Temperature and resistance are inversely proportional. PTC thermistors are positive temperature coefficient thermistors, and the temperature and resistance are directly proportional. These types of thermistors are usually quite accurate, and they are common in thermostats.

PTCs are common in certain types of hard start kits, in which they help take the start capacitor or start winding out of the circuit. They have the same function as a potential relay. The resistance increases with temperature, meaning the PTC gets hotter and raises its resistance until the circuit opens, but it takes a while to reset because it needs to cool down.

Thermocouples work because they generate a voltage in response to a temperature difference between two dissimilar metals. This phenomenon is called the Seebeck effect. Thermocouples are hardy devices used in temperature-sensing equipment, and they measure over a wider range than thermistors. However, thermocouples tend to be less accurate than thermistors.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

How to Save Energy with Grocery Store Refrigeration Jan 11, 2024

This podcast episode focuses on practical ways to save energy with grocery store refrigeration systems, with Matthew Taylor from Kalos Services sharing insights from both a technician and business owner perspective. The hosts emphasize that proper, consistent operation and preventing short cycling of compressors can have a major impact as the largest power consumers.

Proper control strategies, like ensuring evaporator pressure regulators (EPRs) are working, maintaining subcooling, and preventing excessive compressor staging and rapid on/off cycling, are critical for reducing energy consumption. Often, technicians troubleshooting issues bypass these controls when they could be tuned and optimized instead. Matthew stresses the financial benefit for owners when technicians understand the original design intent and how to optimize performance, not just apply a band-aid fix to problems. He advises business owners to track power bill anomalies to catch inefficiencies.

Other key factors covered: ensuring clean evaporator coils, properly functioning doors/curtains, humidity control, condensed maintenance, addressing core issues like suction pressure rather than quick fixes, compression ratio impacts, and coordinating refrigeration with HVAC equipment. Implementing complex new networked equipment has trade-offs as well - while offering more data, it requires different skill sets to leverage.

Topics covered:

Optimizing EPRs and refrigeration controls
Preventing short cycling and improper staging
Following the original system design intent
Tracking power bills to catch system drift
The impacts of evaporator coil cleanliness
Building envelope considerations
Humidity control relationship with refrigeration
Compression ratio and suction pressure optimization
Evaluating networked controls vs. ease of maintenance
Recommissioning

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

An ACCA Form You Probably Never Heard Of w/ Ed J. Jan 04, 2024

The podcast is a conversation between Ed and Bryan about using the ACCA Residential Plans Examiner Review Form, an ACCA form you probably never heard of, to demonstrate that proper HVAC system design procedures were followed based on the Manual J, Manual S, and Manual D guidelines.

Ed introduces the Residential Plans Examiner Review Form as a one-page document that allows contractors to show they gathered the minimum necessary information to complete a proper HVAC system design. The form doesn't teach how to actually do the design calculations but can help explain the design to others not familiar with it, like code officials asking for documentation. The form is meant as a bridge to facilitate communication between contractors and authorities having jurisdiction (AHJs). Ed shares stories of using the form successfully to work with code officials and gain approval.

Bryan asks clarifying questions about the intended audience for the form - whether for residential new construction only or also replacement - since it references the duct design Manual D procedures. Ed explains the full manuals would likely only apply to new construction and add-ons, but elements could apply to replacements if load calculations are required locally. The details depend on the specific project and jurisdiction.

Topics covered:

Purpose and use of ACCA Residential Plans Examiner Review Form
Information that the form documents from Manual J, Manual S, and Manual D
The form's audience (primarily code officials/AHJs, but it's also helpful for contractors)
Applicability for residential new construction, add-ons, and some replacements
Stories of working with local code officials using the standard form
Where to access online - ACCA website and search by full name

Access the document information and examples online HERE and learn more about ACCA at https://acca.org/home.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Solving & Preventing Oil Issues in Rack Refrigeration Dec 28, 2023

In this HVAC podcast episode, hosts Bryan Orr and Matthew Taylor (refrigeration leader and trainer at Kalos Services) discuss oil management and considerations in supermarket refrigeration systems, with a focus on solving & preventing oil issues. They talk about the importance of stable system operation and how oil flows through both active and passive systems in these larger built-up racks.

Matthew explains that in a rack system, oil is actively separated and returned to the compressors through a dedicated system. However, not all oil gets captured this way, so the passive system of oil returning through the refrigeration cycle still occurs. Problems can arise in either system, leading to compressors locking out. Matthew stresses properly setting and regulating EPR valves to minimize load fluctuations that impact system stability.

Common issues covered include clogged oil separators, misadjusted or damaged oil controls, changes in suction pressure affecting oil flow, the impact of floating suction pressures, and troubleshooting overfilled compressors. Matthew offers tips like feeling the oil separator line temperature and using working racks as a guide when unsure of proper settings. The discussion highlights how poor defrost performance can indicate oil trapping issues.

Matthew and Bryan also cover:

Active vs passive oil management in racks
Setting EPR valves for stable operation
Clogged oil separators and failed floats
Suction pressure fluctuations disrupting oil flow
Strategies for floating suction pressures
Steps for readjusting oil controls
Signs of oil trapping issues in the refrigeration cycle
Using working racks to guide troubleshooting

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

What is A2L Mitigation Going to Look Like? w/ Clifton B. Dec 21, 2023

In this podcast, Bryan and Clifton discuss the upcoming transition to A2L refrigerants, like R-32 and R-454B, and what A2L mitigation is going to look like.

These mildly flammable refrigerants will be used in place of R-410A for residential air conditioning systems due to an HFC phase-down driven by legislation and international agreements. They explain what mitigation means with A2L systems - sensors will detect refrigerant leaks, and the system will shut off and turn on the blower fan to dissipate any leaked refrigerant. The mitigation helps minimize flammability risk.

They note the new A2L refrigerants contain no propane despite some misconceptions. The fundamentals of safe installation, service, and repair remain similar but will be absolutely required for A2Ls versus more loosely followed with previous refrigerants. Taking proper time and care is crucial. Bryan and Clifton then discuss the education, training, and resources available from ESCO Group to help contractors prepare for this transition.

Key topics covered:

Upcoming transition to A2L refrigerants R-32 and R-454B
Phase down of R-410A driven by legislation and international agreements
Definition and purpose of mitigation used with A2L air conditioners
Misconception that new refrigerants contain propane
Fundamentals of safe installation and service remain similar but even more vital
Taking the proper time and avoiding rushing is crucial for safety
Education, training, and resources available from ESCO Group
Preparing the HVAC industry for the refrigerant transition
The yearly AHR Expo and HVAC Excellence Conference

You can learn more about ESCO Institute at https://www.escogroup.org/ and explore the HVACR Learning Network at https://hvacr.elearn.network/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Healthy Air Supplements vs. Pillars w/ Kevin Hart Dec 14, 2023

Bryan and Kevin discuss indoor air quality solutions in terms of healthy air supplements vs. pillars of IAQ, drawing an analogy between IAQ supplements like electronic air cleaners and fitness supplements. They talk about why discussing these supplemental products can be controversial since many companies profit from selling them. However, the fundamentals of good IAQ - ventilation, filtration, and humidity control - are proven to work well, just as diet, exercise, and hydration promote good health.

Most contractors focus more conversations and training around supplemental IAQ products versus the fundamentals, which parallels how society embraces fitness supplements over proper diet and exercise. However, a growing group of homeowners want real solutions, and the fundamentals often solve problems better and with less risk than just adding devices. Measuring IAQ and using data-driven diagnoses lead to more targeted solutions, too.

The fitness analogy applies well - you don't jump to supplements first, and adding more supplements isn't always better or healthier. Dosage and application really matter. Contractors should consider focusing 80% on IAQ fundamentals over supplemental products to best serve customers.

Topics covered:

Why discussing IAQ supplements is controversial
Fundamentals of good IAQ: ventilation, filtration, humidity control
Parallels between IAQ supplements and fitness supplements
Reliance on and training around supplemental products versus fundamentals
Growing consumer demand for real IAQ solutions
Using IAQ monitoring and measurement for better solutions
How having more supplements or devices isn't always better
Dosage and proper application really matter
Shifting contractor focus to 80% on IAQ fundamentals versus supplemental products

You can learn more about HAVEN products at https://haveniaq.com/ or become a HAVEN pro at https://pro.haveniaq.com/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Hot Deck, Cold Deck - Short #182 Dec 12, 2023

In this short episode, Bryan discusses the unique features of hot deck, cold deck systems. These systems have separate heating and cooling components (if not entire systems).

Older systems may have completely separate duct systems: one for heating and one for cooling. These ducts would go to each space, and you'd essentially have twice the ductwork you'd expect nowadays. Some systems also have a separate hot deck and cold deck in a single appliance (a bit like gas furnaces with case coils).

We also use the term "hot deck, cold deck" to refer to systems with secondary fluid in a single appliance that produces heating and cooling. Heat recovery or heat-pump chillers use secondary fluids to carry heat around (these fluids don't expand and change state like refrigerant). A traditional chiller is often used in combination with a boiler system, and both can be shut on or off; this configuration can be tricky in shoulder seasons, and a hot deck, cold deck system could be beneficial instead. Buffer tanks also allow energy to be stored in a hot deck, cold deck configuration.

Hot deck, cold deck systems may also be beneficial in humid climates if the cooling component is before the heating component; the system could provide heating, cooling, and dehumidification. You could also use hot deck, cold deck systems for domestic hot water (via a heat exchanger) and cold plunges. It's even possible to use flammable refrigerants in heat recovery chillers that use this configuration.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Common Callbacks and Failed Inspections on Install Dec 07, 2023

In this episode of HVAC School, hosts Bryan Orr and Bert discuss practical tips for preventing callbacks and failed inspections in residential HVAC installs and maintenance.

Bryan and Bert stress the importance of getting the basics right, like properly cleaning condensate drains, ensuring proper drain pitch, and sealing ducts completely before relying on tapes and mastic to cover gaps. They emphasize verifying full system operation at the end of a job, from checking that drains flow freely to testing float switches and pressure testing for leaks. Bryan and Bert also cover wire and breaker sizing for equipment changes, securing disconnects, proper thermostat wall seals, inspecting joints with bubbles to find microscopic leaks, and more thorough evacuations and leak checks.

Throughout the casual, conversational show, the hosts inject colorful commentary on doing quality work with a little sarcasm, including praising the merits of duct board and flex ducts. The tone is partly tongue-in-cheek but drives home the point that shortcuts lead to callbacks and leave clients dissatisfied.

Bert and Bryan also discuss:

Becoming masters of the obvious
Common condensate line issues
The issues with double traps
Ensuring adequate filter access for the customer
Wiring float switches in series vs. in parallel
Sealing ductwork effectively
Using your senses to find airflow leaks in the ductwork
Pressure testing for refrigerant leaks
Common leak points in systems and their causes
Correct electrical setup and markings
Securing outdoor unit placement
Sealing thermostat wall penetrations
Thorough evacuation and leak checks

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

When Permits Are Not Needed - Short #181 Dec 05, 2023

In this short episode, Bryan talks about the situations when permits are not needed to install HVAC/R (or HVAC/R-related) components.

A few codes are universal in residential HVAC, including the International Residential Code (IRC) and the International Mechanical Code (IMC). The local municipality, also known as the authority having jurisdiction (AHJ), chooses which codes to adopt.

You do not need a permit to install plug-in, cord-connected appliances. However, you need UL-listed plugs. You can also replace plugs without needing a permit, but the ratings need to be correct. Anything less than 25v that doesn't put out more than 50 watts of energy also doesn't require a permit. Thermostats and many IAQ accessories, including UV lights, fall into this category.

Portable heating and ventilation appliances, including space heaters and portable cooling units or dehumidifiers, also don't require permits. Evaporative or "swamp" coolers also don't need a permit for installation. Self-contained units with 10 pounds or less of refrigerant and are actuated by motors with

What's Different About Pool Heaters w/ Bert Nov 30, 2023

In this podcast, Bryan Orr and Bert discuss various aspects of pool heaters, focusing on issues that make them different from typical HVAC systems. They cover the basics of pool heaters - the main types (heat pumps and gas heaters) and how they operate similarly or differently from things HVAC techs work on regularly.

The bulk of the 45-minute podcast looks at common service and troubleshooting situations with pool heaters, which are usually installed by pool contractors initially and not HVAC contractors. Bryan and Bert talk through typical causes of common error codes and problems like units frequently going out on high pressure. They cover water flow issues and the role of pressure versus flow switches, the sizing and limitations of heat pumps, low ambient operation challenges, freeze protection, and proper refrigerant charging. There is also a good amount of discussion on gas pool heaters - frequent component failures due to heat and corrosion issues, piping considerations due to their large BTU capacity, and combustion troubleshooting basics.

Throughout the casual discussion, both hosts interject humor and personal stories related to their dealings with pool heater equipment, clients, and installations over the years. The overall message is that while heat pumps and gas pool heaters have some specialized considerations, much of the core knowledge needed to service them comes from foundational HVAC systems understanding combined with an awareness of the unique aspects covered in detail during this episode.

Topics Covered:

Types of pool heaters
How heat pump and gas pool heater operation compare to HVAC
Typical installation and service providers
Key components and design aspects
Common high-pressure issues and troubleshooting water flow problems
Low ambient operation challenges
Refrigerant charging considerations
Gas piping sizing for large BTU appliances
Corrosion issues and component failures
Combustion testing basics

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Farads, Micro and Pico - Short #180 Nov 28, 2023

In this short episode, Bryan explains the fundamentals of capacitance, focusing on the unit of measure: farads, including micro and pico.

Farads are named after scientist Michael Faraday and measure capacitance; one farad represents the capacitance of a capacitor in which one coulomb of charge causes a potential difference of one volt across the plates. Farads measure the storage of electrical energy and indicate the capacitor's ability to create a phase shift.

Since farads are large units, our capacitors are rated in microfarads (1/1,000,000 farads). Bigger capacitors have higher microfarad ratings and store more charge.

Capacitors create a phase shift and limit current on the start or auxiliary winding. (You'll read less current across the start winding than the run winding or common when a run capacitor is in the circuit.) The start winding helps get a single-phase motor up and running (but it isn't present on all motors). Three-phase power has three windings, and it has three sine waves 120 degrees out of phase with each other, all of which can apply directional force. A single-phase motor has two windings and only one sine wave, so it doesn't have that phase difference, making it difficult to start a motor. Capacitors charge and discharge at a different point of the sine wave, causing a phase shift.

A picofarad is 1/1,000,000,000,000 farad, which is smaller than the microfarads we use. However, our meters can auto-range into the picofarad scale if they read a very weak capacitor. You'll have to make sure your meter is reading in the microfarad scale, not the picofarad scale.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

All About 90% Furnaces Nov 23, 2023

Bryan Orr hosted a live podcast discussion all about 90% efficient furnaces with HVAC professionals Ty Branaman, Adam Mufich, and Matthew Bruner. They covered the basics of how 90% furnaces work compared to traditional 80% furnaces, troubleshooting tips, and best practices for installation and service.

A key difference with 90% furnaces is the addition of a secondary heat exchanger that extracts more heat from the exhaust gases before they go out the flue. This allows the furnace to achieve at least 90% efficiency. The condensing of water vapor in the exhaust also releases latent heat. However, the acidic condensate must be properly drained, and pipes must be corrosion-resistant. Proper airflow is also critical.

The experts emphasized starting any service job by carefully looking over the furnace and venting. Check for any signs of problems like leaks, debris buildup, or animals/pests blocking vents. Verify gas supply and use combustion analysis to optimize performance. When troubleshooting, methodically trace through the sequence of operations. Pressure switches, flame sensors, and airflow issues are common culprits.

The podcast concludes with a reminder that extensive training content on HVAC topics like this is available through HVAC School and other industry experts. Continuing education and an open, collaborative mindset are important for professional growth.

Key topics covered:

How 90% furnaces achieve higher efficiency with a secondary heat exchanger
Water condensation and corrosion concerns - importance of drainage and pipe material
Verifying gas supply, venting, airflow, and using combustion analysis
Troubleshooting tips - visually inspecting, tracing sequence of operations, checking pressure switches and flame sensor
Proper installation positioning and intake/exhaust vent sizing per manufacturer specifications

View the entire livestream with Ty on our YouTube channel HERE.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Analog vs. Digital Sine - Short #179 Nov 21, 2023

In this short podcast, Bryan breaks down the differences between analog and digital sine waves.

Analog readings deal with an unlimited number of values; they are very precise and can have any number of decimals. As a result, the alternating current (AC) analog sine readings have very smooth curves when we read them on an oscilloscope (in the US, we see 60 peak-and-valley cycles per second because the frequency is 60 hertz).

Variable frequency drives (VFDs) and ECMs work with digital outputs instead. The alternating current (AC) input is flattened out and then replicated as a direct current (DC) digital output that mimics an analog sine wave using technologies like pulse-width modulation (PWM). Digital outputs appear as a series of steps on an oscilloscope, but PWM doesn't output different "steps" of voltage. PWM just changes the length and frequency according to the duty cycle (percentage of the time energized or unenergized). Digital scrolls turn on and off very often, and the time they spend "on" is the duty cycle, which determines how it stages up and down.

While ECM motor modules usually won't work with regular motors, VFDs can run with typical motors and modify sine waves. These sine waves don't have a smooth curve, but the digital waves can be smoothed out while voltage and current are modified. If VFD-driven motors aren't designed or shaft-grounded properly, electrical discharge machining (EDM) can happen with high-frequency voltage spikes, which can damage the shaft and bearings.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Why and How of Combustion Analysis w/ Tyler Nelson Nov 09, 2023

Bryan Orr interviews Tyler Nelson, an HVAC expert with over 20 years of experience as a contractor. They have an in-depth discussion about combustion analysis and why it is becoming increasingly important for HVAC technicians to utilize this process.

The conversation provides an overview of combustion analysis benefits and why HVAC pros should incorporate it into their standard operating procedures. Tyler offers insightful perspectives from his decades of contracting experience, including his knowledge of how field conditions vary and factory settings may not translate perfectly.

Carbon monoxide poses several dangers to customers and HVAC technicians. Tyler talks about CO poisoning risks and how analyzers can help detect issues. He also covers AHRI Guideline X for cracked heat exchanger testing and emphasizes the need to use combustion analyzers, not just visual inspection, to reliably detect cracks.

Tyler also demonstrates the use of the Sauermann combustion analyzer and mobile app. He highlights key features like replaceable sensors, app control and reporting, and programming for optimum CO sensor protection. He details how combustion analysis allows you to optimize setup, monitor equipment health, and troubleshoot issues.

Tyler and Bryan also discuss:

Why combustion analysis is critical for proper HVAC system installation, maintenance, and diagnostics
CO poisoning and risks to HVAC technicians
AHRI Guideline X
The role of combustion analysis in system commissioning, maintenance, and diagnostics
Sauermann combustion analyzer and mobile app
Advice for technicians to embrace innovations like analyzers while retaining old-school skills and knowledge

Read AHRI Guideline X in its entirety at https://www.ahrinet.org/search-standards/ahri-guideline-x-induced-draft-furnace-heat-exchanger-inspection.

Learn more about Sauermann tools at https://sauermanngroup.com/en-INT, and you can connect with Tyler on LinkedIn HERE.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

“Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Checking a Heat Pump in Heat Mode - Short #178 Nov 07, 2023

In this short podcast, Bryan talks about checking the charge of a heat pump in heat mode. This skill will become more critical as ambient temperatures get cooler.

The most reliable way to check and set the charge regardless of operating mode and season is to weigh the charge. This method is most practical during installation and commissioning, and proper commissioning can prevent issues with charge levels later. Weighing the charge is recommended for big repairs, like major component replacements.

But in many cases, we don't need to check the charge by hooking up gauges; we can check for proper operation by taking a few line temperature readings. Before carrying out any tests or taking readings, make sure the heat pump is defrosted and that you've carried out a full visual inspection. You can carry out a full delivered capacity test in either cooling or heating mode (without the electric heat strips energized) to determine how many BTUs the system is moving. Some simpler tests will require you to compare the discharge vapor line and suction line temperatures to the outdoor temperature and the liquid line temperature to the indoor temperature.

Manufacturers will give specific instructions for their units, including covering the condenser, and they may have charts to help you calculate system pressures based on indoor and outdoor temperatures. If you want to check suction pressure on the low side, you'll always use the common suction port, but you can take either discharge pressure or liquid pressure on the high side.

Bryan also covers:

Critical charge
Ductless system charging practices
Some manufacturer-specific practices
Indoor temperatures and system pressures
R-22 rules of thumb
Total discharge superheat
Staging and capacity considerations
Weighing out when in doubt

Read the tech tip about this topic at https://hvacrschool.com/checking-charge-heat-pump-winter/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

An IAQ & Dehum Case Study w/ Genry & Nikki Nov 02, 2023

Nikki Krueger and Genry Garcia return to the podcast to talk about a recent IAQ & dehumidification case study on a vintage home in Miami. The home was very clean but had a musty odor and VOC concerns. You can read the case study in the “Literature” section at https://www.santa-fe-products.com/about-us/media-resources/ or https://hvacrschool.com/case-study.

Blower door tests and ZPD revealed that the home was leaky, and the crawlspace was also not properly encapsulated. The options were to tighten the building and/or mitigate the problem by improving the HVAC system. The homeowners chose to improve the HVAC, which Genry did by installing a ventilating dehumidifier (Santa Fe Ultra98H), reducing system tonnage (3.5 to 2 tons), and putting in new ductwork.

One of Genry’s key tips to address intermittent moisture issues is to pay attention to fluctuating pressures, not just under the blower door test conditions. Ongoing monitoring is crucial in these studies to measure the home under several different typical conditions. He also relies on blower door tests to determine if encapsulation is necessary or needs improvement, as insulation and encapsulation can bring new issues in their wake.

Extensive testing and working with other contractors (such as home insulators) are the best ways to get a solution that makes the homeowner happy. We need a holistic approach to design to achieve a homeowner’s IAQ and comfort goals, not necessarily following strict design guidelines to a T.

Nikki, Genry, and Bryan also discuss:

Zonal pressure diagnostics (ZPD)
Dehumidifier ductwork
Dehumidifier selection
Attic encapsulation, condensation, and duct leakage
MAD AIR
The importance of IAQ case studies and the insights we can get from them
Effects of insulation
Dehumidifier performance in part-load conditions
Mechanical equipment design
Consulting the ACCA design manuals
Maintaining equipment and sustaining positive results

Stay tuned for the companion tech tip.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Creating a Business Where Everyone Wins w/ Tommy Mello Oct 26, 2023

Skilled trades entrepreneur Tommy Mello joins the podcast to talk about creating a business where everyone wins: business owners, employees, vendors, AND customers.

Tommy's main motivations in business are relationship-building and helping employees make a good living. Those motivations contribute to the development of company culture; even though cultures build themselves naturally, developing the right leaders will help build a positive company culture that values all employees equally. Tommy trains leaders to develop their strengths, shows them that they are valued, and gives them the resources they need to succeed.

When companies grow, communication tools and project management technologies need to be standardized to help organize the company, including using checklists and SOPs. Departments also need to keep their focus on the company's main goal, not just the success of their division. The goal is to make sure that people are aware of their responsibilities early on and on board with the company's vision.

To get the right people on board in the first place, we can improve our recruiting processes if we use social media to recruit talent—people who already have a job and are proven in their roles. Tommy also sees recruiting as a constant process that happens everywhere in the community and requires communication and follow-up.

Tommy and Bryan also cover:

Tommy's business: A1 Garage Doors Service
Training leaders
Allocating responsibilities and getting the right people on the bus
Not punishing people for mistakes
Unifying competition and collaboration
Striking a balance of go-getting and humility
Hiring for your weaknesses
Tommy's new book, Elevate
Building a legacy around serving others
Seeing everyone as an individual instead of a representative
Pricing and integrity

Check out Tommy's latest book, Elevate, at http://elevateandwin.com/. You can also learn more about his 2023 Freedom event in Orlando from Nov 1-3, 2023, at https://freedomevent.com/.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Tips for Supermarket Rack Service w/ Trevor Oct 19, 2023

Refrigeration Mentor Trevor Matthews returns to the podcast to share some of his tips for supermarket rack service. The supermarket refrigeration world is ripe with high-paying opportunities and uses similar skills that HVAC technicians use daily.

Switching from HVAC to refrigeration will require a little bit more attention to some new components, especially controls and control systems. Technically-minded people tend to do well in the refrigeration field regardless of where they come from.

When you're sent to a job site, you'll need to investigate the store and the case (where the refrigeration happens) before checking the controller and looking at the alarms and trends. As with HVAC, you'll want to start by looking for the obvious, like frozen drains. (Even though these systems are designed to freeze, we still need proper airflow and don't want standing water in the drains to freeze.) We don't want to go in there with our tools and start adjusting valves immediately.

Attention to detail is critical in refrigeration. Getting familiar with the details of the equipment, especially by studying the P&IDs, will help you immensely. Being detailed in your service notes and logs will help you and anyone else who might work on the equipment; you can also keep a list of follow-up calls, which allows you to make proposals that bring value to your company, especially in the slower seasons, and prevents emergency service calls later.

Trevor and Bryan also cover:

The growth of Refrigeration Mentor
Moving from an HVAC career to a refrigeration career
Refrigeration dispatch procedure and tips
Ice-bound coils, defrost, and freezing patterns
Service procedures for common drains
Band-aid fixes and re-commissioning equipment
What to keep in a detailed log
Quality vs. quantity of work
Bringing value to your grocery refrigeration clients
Positives and drawbacks of the refrigeration industry

Check out some of the great training Trevor offers through his Refrigeration Mentor program at https://refrigerationmentor.com/. You can also email Trevor at trevor@refrigerationmentor.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Traps, Vents & Drains - Short #177 Oct 17, 2023

In this short episode, Bryan covers traps, vents, and drains. He explains some common misconceptions and best practices for fabricating drains, especially in residential and light commercial structures in Florida.

Cleanouts and vents are commonly confused with each other, and people often cap vents and leave cleanouts open. However, cleanouts (which must be capped) will always be before the trap, and vents come after the trap. When you have an indoor air handler, furnace, or fan coil, vents must be higher than the drain pan to allow the float switch to trip when the drain backs up. (Rooftop units have shorter vents.) Vents should stay open. We use static pressure to determine the trap depth, and the trap outlet must be shorter than the inlet.

The best practice for drain pitch is to have 1/4" of fall for every foot of horizontal run, and we must avoid making double traps where air can get trapped between them. Vents prevent air bubbles from forming in drains with multiple traps. Double traps often form when drains are not supported properly and sag over time; using proper support in your installations is the best way to prevent that from happening.

In Florida, we often use only one trap and still get drainage. A typical installation has a cleanout, a trap, and a vent higher than the drain pan, all on a downward pitch. However, we also get severe condensation on our drains, and we must insulate the horizontal PVC runs to prevent sweating. In multi-family applications with common drains, each individual needs a trap and then a vent before the main drain.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Cracking the Home Health Comfort Code: IAQ’s Illusory Ideals Oct 12, 2023

HAVEN IAQ founder and CEO Kevin Hart returns to the podcast to discuss cracking the home health comfort code, diving into IAQ’s illusory ideals.

Even though the industry has been generating well-thought solutions to common problems, it’s difficult to put those solutions into practice on a large scale. As a result, it’s common to rely on selling “bolt-on” IAQ products, which don’t actually solve systemic IAQ problems. HAVEN’s recent work has also shown that only a few HVAC technicians are proactively offering IAQ solutions to homeowners; the vast majority wait for the owner to ask about a solution instead.

Some IAQ issues stem from duct and building envelope leakage, meaning technicians could offer to perform diagnostic tests (like blower door testing) and address the solution holistically with building envelope and duct sealing. However, not all customers are willing to pay for these, which is one of the biggest challenges of comfort consultations. The question about the real long-term, widespread effectiveness of comfort consults remains to be answered.

Right now, we only have the illusion that IAQ problems are being solved. We might see positive changes to the state of IAQ if there is more forethought on the technician’s part to include diagnostic tests in their quotes when it makes sense to do so. Our industry may also see more proactivity in the quest to solve IAQ problems holistically by establishing sales goals and approaches.

Kevin and Bryan also cover:

Latest HAVEN IAQ developments
The IAQ status quo
Technicians and sales
Evolution of evacuation best practices in the field
Proactivity vs. reactivity when addressing IAQ problems
IAQ solution goals and approaches
The value of commissioning reports
DIY and consumer-based IAQ solutions
“Getting in the reps” when using diagnostic tools to solve problems
The benefits and challenges of selling diagnostic services

Learn more about HAVEN at https://haveniaq.com/ or become a HAVEN Pro today at https://pro.haveniaq.com/. You can also contact Kevin directly at kevin@haveniaq.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

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Tubing Insulation Tips - Short #176 Oct 10, 2023

In this short podcast episode, Bryan goes over a few tubing insulation tips. Tubing insulation is also commonly known as Aeroflex, Armaflex, and Thermaflex—all brand names for black copper line set insulation.

We typically have to insulate just the suction line in typical residential split HVAC systems, but you'll typically have to insulate both lines in ductless/VRV/VRF or refrigeration applications. The insulation should be on the tubing before brazing, gluing the ends together (only using a specialty tubing insulation adhesive, NOT duct tape!). Since these adhesives are types of contact cement, you will need to apply a thin coating on each side of the joint and wait for a few minutes before pushing the ends together. Some forms of tubing insulation are split and have an adhesive flap instead.

Then, you'll want to hold the insulation back with a clamp about 8-10" away from the area where you're brazing to protect it from heat damage. When you finish brazing, you'll want to put the insulation back and make sure all necessary areas are covered. In cases where it's practical, especially in residential HVAC, pulling the insulation over the 90s and P-traps may be the best bet due to its smaller margins for error. However, mitered fittings may be required in larger systems.

To assemble mitered fittings, use either a miter box or the template on the tubing insulation box. It's a good idea to use the disconnected tubing and make a mitered fitting on the bench as a template before making more—the tails can be a little long. Do NOT use the saw that comes with the miter kit—you will be fine with a very sharp knife that makes a smooth edge (and be safe!).

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

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The New HSI Module from White Rodgers Oct 05, 2023

Jim Fultz returns to the podcast to talk about the new HSI module from White-Rodgers, the 50E47U-843. You can learn more about this new universal HSI module at https://hvacrschool.com/hsimodule.

Hot surface ignition modules control the burner for gas appliances that use hot surface ignition, not just furnaces. Since the HSI module doesn't need to work with a blower fan, it can be used in water heaters, pool heaters, and many more appliances that don't primarily move air (except for combustion). It also controls the inducer blower and monitors the pressure switch.

All White-Rodgers universal ignition modules work with the WR Connect app, which allows users to set up controls with a smartphone via NFC technology. The controls do not need to be powered on, and users do not need to be online during use. Users can also use the app to auto-configure their new White-Rodgers controls based on the old control settings. Technicians aren't required to use the app and can configure controls manually if desired.

Universal controls that all operate similarly, like the White-Rodgers ignition modules, are great for creating a consistent workflow and establishing truck stock. In HVAC businesses and in the field, these modules are great for delivering efficiency and quality. The 50E47U-843 also shows real-time flame current, eliminating the need for technicians to wire flame sensors in series with their meter for testing.

Jim and Bryan also cover:

Emerson, Copeland, and White-Rodgers
Hot surface ignition vs. other types of ignition
Integrated furnace controls (IFCs)
How near-field communication (NFC) technology works
Fault codes
Electrical inputs and outputs
Local vs. remote flame sensing
Integrated thermostat sensor for infrared and tube heaters
WR Connect, WR Mobile, and Copeland Mobile apps

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

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Locked Compressors and Hard Starts - Short #175 Oct 03, 2023

In this short podcast episode, Bryan talks about locked compressors and hard starts. He explains what actually happens when a compressor locks and covers when and how to use hard starts appropriately.

Locked compressors are compressors that trip on overload during startup; they're considered "locked" because the rotor doesn't turn inside the stator and generates heat instead. The overload opens, but the compressor shell typically does not heat up very much when the overload opens.

When you have a locked compressor, you need to start investigating the root cause with a thorough visual inspection. Then, check the run capacitor. A hard start kit helps you get the equipment working, but we should make sure we've addressed underlying electrical issues or installation conditions before installing a hard start kit. If the unit is old, then we may use a hard start as a temporary solution until the customer can purchase a new unit. In any case, it's best to use a factory hard start if the system requires it, but it's okay to use an aftermarket hard start kit to get an old system to run.

Hard start kits consist of a start capacitor in series with the start winding, which moves more current into the start winding and decreases the time it takes to start the compressor; lower current readings indicate a faster amperage drop, as most ammeters read timed average values. The potential relay needs to open to take the start capacitor out of the circuit so that we don't continuously apply additional current to the start winding, which hurts the compressor over time. The hard start kit is not a silver bullet that solves all problems, and we need to know when to use them and how to use them appropriately.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

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Residential Exhaust Codes and Best Practices Sep 28, 2023

Licensed mechanical engineer Tony Amadio joins the podcast to talk about residential exhaust codes and best practices. He also put together a presentation about the topic, which you can view at https://hvacrschool.com/exhaust.

When choosing duct materials for residential exhaust, you will want to stick to sheet metal and mind the gauge; flex ductwork can easily be damaged and will rack up a high total equivalent length in a way that sheet metal will not.

Exhaust air should always discharge outdoors, not into an attic or crawl space, and that air needs to be replaced by air entering the conditioned space; makeup air is the air we draw in to replace the exhausted air, and we need appropriate undercuts to make sure we're getting the right amount of makeup air.

Domestic cooking exhaust may also come in a few different varieties, each of which has different code requirements (with downdrafts needing much more CFM per ASHRAE). Range hood shape is also important for capturing as many particles as possible, but makeup air kits are usually unnecessary (and could be more of a hassle than they're worth).

When it comes to bathroom exhaust, the CFM requirements differ between residential and light commercial, as well as intermittent and continuous exhaust. Steam generators may also be present, and they require extra consideration.

Tony and Bryan also cover:

Tony's education and career background
Discharging and terminating exhaust air
Insect screens
Makeup air in light commercial applications
Clothing dryer vs. bathroom vents
Ductless clothes dryers and condensate piping
Home Ventilation Institute (HVI) guidelines
Pressure imbalance in a structure
Residential vs. light commercial bathroom exhaust
Static pressure, blower sizing, and exhaust duct sizing

You can ask Tony questions by email at anthony.amadio@peloadcalcs.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

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Wiring Refrigerated Cases w/ Nathan & Phil Sep 14, 2023

Phil Barr and Nathan Orr join the podcast to talk about wiring refrigerated cases in commercial spaces, including convenience stores and supermarkets.

Cases may be medium-temp (or high-temp, in some cases) or low-temp. Medium-temp cases can typically defrost on their own during the off cycle, and low-temp cases may have electric or hot-gas defrost to help get ice off the coil at set intervals. Each system has an evaporator (and fans), compressor, condenser, and metering device (often a TXV or EEV), and low-temp refrigeration may have anti-sweat heaters, EPRs, and other components to manage.

Challenges arise when electricians don't understand the fundamentals of commercial refrigeration, especially as the electrical circuitry relates to the refrigeration circuit components. Time crunches also apply a lot of pressure to electricians and refrigeration technicians. Testing circuits, such as fans and lighting, or using circuit tracers are good ways to get an idea of how an existing system is wired. Labeling wires and breakers and keeping those labels or information in places where others can read them can help you and other electricians in the future.

One of the most common issues happens when technicians or electricians refuse to test out their results to catch their mistakes before callbacks happen. Even seemingly small electrical issues, such as improper lighting, can cause costly losses if product spoils and cannot be sold.

Phil, Nathan, and Bryan also cover:

Changes in central and case control strategies over time
Challenges with retrofits and remodels
Central lighting controls
Mistakes that can be made when labeling wires or breakers
Working against the clock
Terminal blocks, DIN rails, and connectors
Making mistakes and the origin of animosity

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Things to Keep out of the System - Class Sep 07, 2023

This podcast is a class taught by Bryan: Things to Keep Out of the System. He covers some installation best practices along the way to keep contaminants and non-condensable gases out of the system.

We want to keep air, water, dirt, copper shavings, solvents, and nitrogen out of an operating system. All we want in an operating system is the appropriate oil and refrigerant for the system. Unfortunately, the POE and PVE oil we mostly use in residential systems nowadays are very hygroscopic; they attract water, and POE mixes with water to form acid, another thing we want to keep out of the system.

We can pull most of the moisture out of the system by pulling a deep vacuum and following the best practices for a fast and deep evacuation. However, we can also reduce the probability of moisture getting into the system in the first place by NOT working on copper while it's raining outside, sealing the copper tubing adequately when routing it underground or in a chase (a common installation practice in Florida), and insulating it properly.

Dirt can easily get into the system when we're modifying piping, especially when adding fittings or reaming, but we can use nitrogen or line set cleaners to flush it out. Purging the lines and flowing nitrogen while brazing also help keep air and water vapor out of the copper lines. When deburring, try to avoid letting the burr or copper shavings from falling into the tubing.

Bryan also covers:

Drawbacks to running copper underground
Oil return and miscibility with refrigerant
Flowing nitrogen without a regulator
Leak detection and nitrogen pressure testing
Why we should ream or deburr copper to prevent leaks
Being able to trust your equipment

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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ACH (Air Changes Per Hour) - Short #174 Sep 05, 2023

In this short podcast, Bryan talks about air changes per hour, also known as ACH, and what it means in HVAC design and indoor air quality (IAQ) discussions.

ACH tells us how frequently the entire volume of air in a room or structure is replaced; we are referring to the cubic feet of air leaving a space and then being replaced within that same space. If we have a balanced number of cubic feet per minute (CFM) of air supplied to and returned from the room in one hour, we would multiply that CFM by 60 to get the ACH, as there are 60 minutes in one hour. ACH should not be used to calculate heat loss and heat gain, even though BTUs are moved with air.

ACH is a practical guideline for HVAC design. Ventilation needs will vary based on the purpose of a room and the number of occupants in it, and ACH tends to be a more important factor for determining how we can meet ventilation needs in commercial and industrial structures than in residential structures, in which we mostly rely on Manual J calculations of sensible and latent BTU gains and losses. However, we should not confuse ACH with outdoor air ventilation requirements as described in ASHRAE Standards 62.1 and 62.2.

ACH also comes into play when it comes to infiltration and the tightness of an entire structure. When used in the context of blower door testing, the ACH will tell us if a building meets tightness standards. There is also a term called ACH50, which refers to air changes per hour at the standard pressure for blower door testing: -50 Pascals. ACH50 does not reflect ACH under natural conditions (ACH natural).

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Oil Return and Refrigerant Charge in VRV w/ Roman Baugh Aug 31, 2023

Roman Baugh joins the podcast to talk about oil return and the refrigerant charge in VRV systems.

VRV systems—also known as variable refrigerant volume (or variable refrigerant flow/VRF) systems—have one outdoor unit, one or multiple compressors, and multiple indoor units. The outdoor unit modulates to meet the indoor units’ fluctuating demands. They are versatile and flexible systems.

Like parallel racks, VRV systems have long lines and a lot of piping, so oil return and refrigerant charge are especially critical. VRVs have specific control protocols, as they need refrigerant volume and velocity to move oil and keep it lubricating the compressor for its entire lifespan; oil return mode, the refrigerant charge, and the piping protocols are supposed to support that function.

When it comes to piping protocols, line sizing is critical. Whenever there is a need to relocate the outdoor unit and change the piping configuration, the charge needs to be adjusted, and the piping may even need to be upsized to prevent restrictions from happening. Daikin has VRV WebXpress (and SplitXpress) software for equipment selection; the goal is to help installers out with the line length and charging whenever it needs to be changed.

When trying to get the oil return and line sizing right, you ultimately need to look at the manufacturer’s literature and resources. It also helps service technicians if the installer makes the charge and line information readily available to anyone who works on their VRV install in the future.

Roman and Bryan also discuss:

Where and how oil can settle in VRVs
Consequences of improper charge in VRVs
Liquid lines in VRVs
Violating piping rules and safety protocols
Vertical separation in liquid line sizing
Suction line sizing
POE and PVE oil miscibility
Daikin’s resources

Check out daikincity.com to find Daikin’s literature and software programs.

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Magical Air Cleaning Oxides? - Short #173 Aug 29, 2023

In this short podcast, Bryan talks about oxidation and all the buzz behind “magical air-cleaning oxides” and other similar IAQ products.

Oxidation is the loss of electrons, and reduction is the gain of electrons; oxygen commonly loses electrons. Rusting is a common example of oxidation; it happens when iron and oxygen interact in air or water. Metals that are more likely to react with oxygen (or corrode) are “less noble” than more noble metals. Less-noble metals, known as anodes, are sometimes used sacrificially to prevent the oxidation of nobler base metals, known as cathodes.

While iron oxidation results in corrosion, some IAQ products use the process to bind oxygen molecules to unwanted substances. The IAQ products that use oxidation use the natural tendency of oxygen to lose electrons when bonding with other molecules. Ozone is a common agent of these IAQ products because an ozone molecule is very unstable and has three oxygen atoms, meaning it combines with other molecules via oxidation; it stabilizes other unstable molecules. Ozone, however, also reacts similarly with cells in our respiratory system and can cause irritation.

In our industry’s efforts to reduce the negative effects of COVID-19 viruses, oxidation has generated a good deal of interest. Nowadays, some IAQ products use smaller amounts of ozone or use activated carbon to catch ozone before it enters the conditioned space. Many manufacturers that use oxidation as a strategy use other ion-based oxidizers, just not ozone. Some of these oxidizers can break pollutants into aldehydes and other chemicals that may harm our bodies.

If you want to learn more, you can read Oxidizers and What It Has to Do With COVID-19.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Can Filters Capture Viruses? - Short #172 Aug 22, 2023

In this short podcast, Bryan talks about filtration and IAQ, especially as they relate to virus control. He also answers the age-old question: “Can filters capture viruses?”

While it may seem like particle size matters when it comes to filter efficacy, filters are not nets that strain air particles and prevent pollutants from passing through. When we talk about particles, we tend to focus on ones that are 0.3 microns in diameter, which tend to be medium-sized particles. Viruses tend to be among the smallest particles that we aim to control when it comes to IAQ.

Filter media are crisscrossed fibers that catch particles in different ways. Inertial impaction is one means of stopping particles from passing through; the initial impact stops the particles from passing through. Interception happens when particles graze filter fibers and get stuck. Electrostatic attraction relies on energy to attract and catch particles. Diffusion happens when smaller particles move more erratically due to Brownian motion and get caught in the filter media.

Viruses are among those smaller particles. Smaller particles’ erratic motion makes them more likely to collide with the filter media, so they aren’t necessarily harder to catch. Higher MERV ratings are associated with higher capture efficiencies. HEPA filters surpass the MERV scale and have also been proven to filter viruses out of the air, but we rarely use true HEPA filtration in residential HVAC because they are too restrictive for total system airflow. We can use bypass HEPA filtration to filter the air without creating a massive restriction at the unit. Large filter-back returns with 2” filters can help catch more particles with a greater surface area without tanking the static pressure.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Heat Pumps + Inverters w/ Joey H Aug 17, 2023

Joey Henderson returns to the podcast to talk about heat pumps and inverters.

The reversing valve, defrost cycles, and auxiliary heat can cause confusion for people who have primarily worked with furnaces or straight-cool A/C systems. Heat pumps use defrost cycles and bring on the auxiliary heat when the coil is ice-bound, which can present a challenge; we need to maintain cold coils without going into defrost all the time.

Even though heat pumps were significantly less effective in years past, we will still see reduced performance in very cold conditions with the newer inverter-driven systems. Proper design, installation, and commissioning will also help occupants get the best performance out of their heat pumps.

Inverters offer plenty of advantages for the cooling aspect of heat pumps, too, especially when it comes to achieving longer runtimes for dehumidification. They can also float their coil temperature, much like how refrigeration systems can use floating suction or head pressure. Condensate assemblies absolutely must be run properly to prevent backed-up drains and other related problems. Liquid line sizing and proper commissioning are also especially crucial for ductless inverter-driven systems.

Joey and Bryan also discuss:

Heat pump training and the electrification initiative
Balance point
Defrost strategies and universal defrost boards
Dual-fuel systems
Heat pump stigmas
Blower door testing in various climate zones
Surge protection and voltage monitoring
How inverters work
Occupant lifestyles and latent loads
Zoning and duct design for inverter-driven systems
Critical charge
Line length for ductless systems

Check out Joey's training, social media, and contact information at https://joejoehvac.com/. You can also check out Craig Migliaccio's book about mini-splits at https://www.acservicetech.com/mini-split-book.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Get Air Where it Needs to Go W/ Joey H. Aug 10, 2023

Joey Henderson joins the podcast to talk about airflow and how we can get air where it needs to go.

Duct design is one of the subjects that fuel Joey's passion for HVAC. In many cases, people focus too heavily on the equipment when diagnosing airflow problems; sometimes, the equipment simply can't perform as it should due to a poorly designed duct system. In residential HVAC, many duct systems aren't adequately planned out, and the airflow can't overcome restrictions like filters. We also need to keep in mind that flex ducts need to be as straight and tight as possible, and it's usually best if we slightly upsize them (compared to sheet metal).

Even though balancing dampers aim to solve airflow problems, they often lead to other issues when installed and used incorrectly. In many cases, proper duct design would solve problems without the need for balancing dampers. Bypass dampers are also commonly misapplied.

Some technicians also aren't properly trained to position their static pressure probes appropriately to measure total external static pressure, which leads to faulty readings and misinformed diagnoses. We can start by looking at things that can improve system performance at the equipment, like filtration; we can think of the equipment as the heart and the duct system as arteries (with static pressure as blood pressure), and the equipment also has the biggest pressure drop.

Joey and Bryan also discuss:

Joey's HVAC beginnings in the Navy and current work in education
Educators' unique communication styles
Learning from other educators as an educator
Plenum boxes and turbulence
Using wye fittings
Laminar flow
Modifying existing duct systems
Motors and amp draw
Building duct transitions
Clients and money limitations
Communicating with customers about airflow issues
Ethics around duct design
Unique duct challenges with inverter-driven systems

Check out Joey's training, social media, and contact information at https://joejoehvac.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Business Round Table - Tersh, Peterson, Holt Aug 03, 2023

This podcast episode contains some of the questions and topics from the Business Round Table at the 4th Annual HVACR Training Symposium. Panelists include Tersh Blissett, Luke Peterson, and Andy Holt.

One of the most critical parts of HVAC business ownership is knowing when to grow your business (i.e., hiring more techs and incorporating standalone maintenance and install departments). Ultimately, we need to think about how many service calls we're assigning to each technician per day and how many customers we have to turn down due to a busy schedule. Getting family members involved in the business can also have a range of positive and negative effects on a business.

Delegating is another important skill that can help you run an HVAC business smoothly and focus on ownership and management over your day-to-day tasks. You need to understand your business's core processes but can delegate tasks that take time away from developing your business.

When it comes to economic issues like inflation, we need to be looking at our own costs and competitors' costs to set our prices and pay our employees appropriately for the economic climate. We can use indicators like the consumer price index to assist with pricing and setting pay rates.

Tersh, Luke, Andy, and Bryan also discuss:

Key performance indicators (KPIs)
Maintenance agreement frequency
Talent acquisition vs. vetting
Attracting vs. poaching employees
Merit-based raises vs. cost-of-living raises
Working "in" the business vs. working "on" the business
Hiring people to handle day-to-day tasks
Using Loom or similar video instruction software
Support systems in your interpersonal relationships
Motivation for starting a business
Starting a business from scratch vs. acquisitions
Explaining the difference between bids and online retail prices

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Check out our handy calculators HERE.

Cap Tubes and Flow Facts - Short #171 Aug 01, 2023

In this short podcast, Bryan goes over some information about cap tubes (capillary tubes) and flow facts.

Cap tubes are metering devices; they're long tubes with small diameters, and their flow rates are dictated by the tubing diameter size and tube length. Pistons and TXVs are some of the most common metering devices in residential HVAC, and flow restriction doesn't just happen at the metering device; distributors also contribute to the pressure drop and act like small capillary tubes in addition to the metering device. Older units, simple refrigerators, and window units are more likely to have capillary tubes as metering devices, as cap tubes are an easy and versatile use of small-gauge tubing.

The diameter is the primary factor that influences the flow rate, and length is usually secondary. However, longer tubes cause the fluids to encounter more resistance (in the form of friction) as they flow from one end of the tube to the other; the longer the tube, the lower the flow rate. Longer tubes also cause the fluid velocity to decrease more than a short tube.

When you have long runs of small-diameter tubing, you can replace a few sections with larger-diameter tubing to improve the flow rate. Sometimes, the ends of cap tubes are in hard-to-reach places, so replacing middle sections with larger-diameter tubing will still help decrease the static pressure and friction in the tubing.

Oil traps and risers may be smaller than other areas of tubing, and they have a larger pressure drop and more friction associated with them. (However, the smaller tubing also increases the fluid velocity.) The same principle applies to 1/4" vs. larger-diameter vacuum hoses.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Filter Driers and System Cleanup w/ Copeland Jul 27, 2023

Jim Fultz and Jim Hagl from Copeland join the podcast to talk about filter driers and system cleanup. Filter driers come in many types and sizes; they typically go on the liquid line (bi-flow filter driers are used on heat pumps), but suction line filter driers also exist.

Copeland’s liquid line filter drier models include the EK (premium), BSL (smaller diameter), BOK (with HH desiccant to assist with burnout cleanup), and CU (copper spun). Bi-flow filter driers in Copeland’s lineup include the BFK and BSB categories. These liquid line filter driers protect the metering device and should typically be installed as close to the metering device as possible (with some exceptions for heat pump startups in heating mode). These filter driers typically need to be replaced anytime the system is opened for service, the pressure drop across the drier exceeds 3 PSI, or the system is wet.

Suction line filter driers in Copeland’s lineup include the ASD, SFD, and CSFD models, all of which come in different shapes and sizes for varying applications. The ASK suction line filter drier has activated carbon to assist with burnout cleanup. When used to assist with contamination cleanup, suction line filter driers must be taken out of the system within a few days.

Jim F., Jim H., and Bryan also discuss:

Copeland and Emerson brand realignment
Filtration data
Myths about smaller-diameter filter driers
Copper-spun drier uses and applications
Ideal vs. accessible suction filter drier placement
Desiccant considerations
Filter drier selection best practices
Moisture indicators
Restricted filter driers
Filter drier sizing and system charge
Bi-flow driers in straight-cool systems
Dealing with factory-installed filter driers
Product names and suffixes
Burnouts and oil
Flowing nitrogen while brazing
Additives and flushes

Check out Copeland’s filter driers at https://hvacrschool.com/copeland-driers.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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So... What Do You Do? - Unconformed - Short #170 Jul 25, 2023

In this short episode, Bryan goes over the fourth chapter of his new book, Unconformed. The chapter is called "So... What Do You Do?"

Parents always want to be proud of their children, but it seems as though children are more proud of children who attend college than take up apprenticeships. However, these feelings largely seep in due to peer expectations; we want our children to measure up to our friends' standards or success, not necessarily our own. Parents are also less likely to encourage their children to get into the trades and value the time and expertise of tradespeople.

All jobs, even less prestigious jobs, matter and have a purpose. Society tends to devalue tradespeople and manual laborers, but those jobs do a great service to society. Nevertheless, the competitive drive between parents and our fear of failure makes us fall into these mindsets where we devalue manual labor. The media and family members also trap us in these expectations.

Society runs on the ability of people to solve problems and innovate, which means that blue-collar work is necessary for society to function. Not to mention, popular media and DIY culture have also brought attention to the artistry of the skilled trades. These positive changes are important to the perception of blue-collar work, and we can accept (and encourage) a child's choice to find purpose in the skilled trades, not just blindly seek happiness.

Bryan also covers:

Networking
Expectations vs. standards
The pitfalls of happiness
The merits of working with our hands

You can purchase Unconformed on Amazon's website HERE.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Pipefitting Best Practices Jul 20, 2023

This podcast is based on a Kalos meeting about pipefitting best practices, particularly in commercial refrigeration applications. It begins with a few words about quality workmanship by the Kalos founder and CEO, Robert Orr.

Pipefitting consists of repairs and joining metals; when joining metals, we need to liquify the alloy and draw it into the joint via capillary action. When pipefitting, oxygen can present some problems by coating the inside of the pipe with oxides that can contaminate the system. We can reduce the likelihood of oxide formation by flowing nitrogen while brazing; purging nitrogen displaces the oxygen in the lines before brazing, and flowing keeps oxygen out during the brazing process.

Tip selection will be based on the piping diameter; tips that are too small won't adequately heat the pipe, and tips that are too large will consume too much fuel. You'll also need to leak-check your torch tanks and ensure that you have the appropriate ratio of oxygen to acetylene by aiming for a neutral flame rather than a carburizing or oxidizing flame.

After brazing, we need to perform a nitrogen pressure test to ensure that the system is leak-free. Then, once the pressure test is passed, we should evacuate the system to keep the system clean, dry, and tight.

Bryan, Matthew, Roman, and Nathan also cover:

Brazing vs. soldering
Properties of base metals
Alloy properties and appropriate uses
Mineral oil vs. POE oil and cupric oxide
Safety practices and PPE
Preparing copper (sealing, deburring, etc.)
Valve seating
Penetration and the gaps between surfaces
Base metal temperature indications
Advantages of nitrogen for pressure testing
Vacuum pump best practices
Micron gauges

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Filter Driers and System Protection - Short #169 Jul 18, 2023

In this short episode, Bryan talks about filter driers and their important role in HVAC/R system protection, especially in accordance with Copeland's (formerly Emerson's) AE24-1105 R5.

We can really start keeping our systems contaminant-free by handling tubing properly, purging and flowing nitrogen, and keeping copper shavings out of the tubing when deburring or reaming. Suction and liquid filter driers protect the system during operation and are designed for specific purposes.

We typically don't install suction filter driers in residential systems unless we're fixing a system with compressor burnout or acid contamination; in those cases, we also want to make sure we replace accumulators and clean out the line set as well as we possibly can. Commercial refrigeration tends to have more rigorous contamination prevention protocols, including testing oil for acid and installing suction filter driers in everyday operation, due to the use of multiple compressors in a single system.

However, suction driers are recommended in ALL applications per AE24-1105. In many cases, we don't install them in systems because they can create a significant pressure drop in the suction line and damage the compressor, but suction filter driers can provide a net positive effect if we monitor them. We should install suction filter driers as close to the compressor(s) as possible, and we should cut them out when we need to remove them, not unsweat them.

Bryan also covers:

Liquid line filter drier placement
Pressure drop across filter driers and replacement thresholds
Burnout cleanup procedures
Filter drier sizing
Refrigerant additives
Motor burnout in hermetic refrigerant-cooled compressors
Electrical best practices

For more information about filter drier selection by model number, visit https://hvacrschool.com/copeland-driers.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Alex Meaney - HVAC Design Backwards, Forwards, and In Between Jul 13, 2023

This podcast episode is one of Alex Meaney's HVACR Training Symposium presentations: HVAC Design Backwards, Forwards, and In Between.

Load calculation factors in all three means of heat transfer: conduction, convection, and radiation. It doesn't directly tell you the tonnage; it just tells you how many BTUs (sensible and latent) are entering or leaving a structure. When designing systems after doing load calculations, we need to be mindful of industry standards and their pitfalls, as well as the climate conditions and the difficulty of obtaining manufacturer data.

Equipment selection by tonnage is only part of the picture when it comes to HVAC design; we also need to factor in airflow and duct design, especially duct sizing. However, many rules of thumb and poorly explained terms are counterproductive to a thorough understanding of HVAC design. In some cases, the best way to design a system may seem "backward," especially when starting with blower selection instead of ductwork.

Duct design is particularly difficult, especially when software identifies several problems with designs that seemed to look good on paper. However, the software points out areas where you can adjust the duct size and manage restrictions to allow the fan to do its job without being derated by friction.

Alex also covers:

Insulation and efficiency ratings
CLTD Groups
Tricky radiant gains and losses
The relationship between BTUs and tons
AHRI ratings
Shortcomings of Ductulators in duct design education
Pressure vs. friction in ductwork
Static pressure vs. velocity pressure
Measuring friction with pressure
Regulations vs. reality
Furnace static pressure range
Differences between commercial and residential duct design
Oversized and under-ducted systems
Variable-capacity systems
ACCA manuals and tables

Check out Alex Meaney's consultation business at https://www.meanhvac.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Santa Fe Panel with Andy Ask and Ken Gehring Jul 06, 2023

This podcast is the Santa Fe Panel from the 4th Annual HVACR Training Symposium. The panel focused on dehumidification, was moderated by Nikki Krueger, and featured Andy Ask and Ken Gehring.

"Matchmaking" a residence to the climate requires us to design and install equipment that keeps occupants healthy and comfortable. HVAC contractors need to focus on the dew points, especially as they remain high at night and in the shoulder seasons. Humidity loads tend to hold steady (even peak dew points), while sensible loads increase and drop, making it difficult to control latent heat loads the same way we control sensible loads.

The equipment will typically be less efficient if you focus on long runtimes to remove latent heat under partial load conditions and maintain 50% humidity. Dehumidifier efficiency is determined on a pint per kilowatt basis, but a constantly running dehumidifier will do its job a lot more efficiently than one that starts and stops regularly.

The dehumidifier adds heat to the house and should only come on when the HVAC system is having trouble maintaining the desired humidity load; the dehumidifier has a reheat effect, but the HVAC system will need to deal with the increased heat load. When you add a whole-house dehumidifier, adding a fresh air ventilation component is highly recommended.

Nikki, Ken, and Andy also cover:

Infiltration and exfiltration
Variable-speed technology and supplemental dehumidification
Fresh air ventilation
Air conditioner vs. dehumidifier latent heat removal
Net zero HVAC, electrification, and decarbonization initiatives
Air mixing in the ductwork
Standalone dehumidifiers
Vapor pressure and buoyancy
Sizing for peak dehumidification loads
Dehumidifier supply and return tie-ins
Static pressure and "injection" dehumidification
Fan cycling

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Where to Place the Micron Gauge - Short #168 Jul 04, 2023

In this short podcast, Bryan talks about where to place the micron gauge during evacuation and how to think about micron gauge positioning.

Evacuation (deep vacuum) doesn't remove solid contaminants, and vaporizing liquid water is a time-consuming process; its main purpose is to remove water vapor, air, and nitrogen gases from the HVAC/R system. When you pull down below 500 microns and hold that pressure, we can make sure we have a clean, dry, and tight (leak-free) system. As we started using R-410A and POE oil, water in the system became a much bigger issue than it was with mineral oil (it was never to have water in the system, but it breaks down POE oil).

Before we start pulling a vacuum on the system, we need to attach our micron gauge to the pump while it's isolated to make sure the pump is working. A modern vacuum pump should pull down below 100 microns in 30-60 seconds; if your pump can't pull down to 100 microns in under a minute when isolated, then you'll want to change the oil (possibly multiple times). Be sure to change the oil regularly and store it properly.

When you pull a vacuum on a system, you'll want to attach your micron gauge as far away from the pump as possible to get an accurate indicator of your vacuum. Use core remover tools to isolate the system and make sure the far side of the system is brought below 500 microns during evacuation. The time it takes to pull down a system and the time you'll hold the vacuum will depend on your application (residential vs. commercial).

Check out Review of Vacuum for Service Engineers (revised by Jim Bergmann and Bryan Orr, 2020) at https://www.trutechtools.com/accutools-review-of-vacuum-for-service-engineers.html.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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From Resi Tech to Industry Leading Refrigeration Trainer w/ Brett Wetzel Jun 29, 2023

Brett Wetzel joins the podcast to talk about his journey from resi tech to industry-leading refrigeration trainer.

Brett is best known for his educational content, but he is also the manager of technical troubleshooting and training at CoolSys. The skills gap is widening, and CoolSys was inspired to create a solution to that problem. Brett's goal is to offer training that provides education and a sense of community all at once. Since he likes to keep his training simple and establish a solid foundation for his students, one of Brett's favorite training practices includes going over a system's P&ID diagram with his students before even looking at it. He focuses on classroom engagement and keeping trainees interested.

Brett does regional training sessions and has written technical documentation to help technicians. As he has shifted from a field role to a full-time educator role, he has noticed that he has had more time at home. CoolSys focuses on commercial and industrial refrigeration, including system components, racks, and controls.

The transition from residential HVAC to commercial HVAC and refrigeration requires an inquisitive mind and a drive to keep learning. Independent learners tend to do particularly well. There is an additional step that people will have to take when they move from fieldwork to education; communication skills and an ability to keep students engaged are crucial.

Brett and Bryan also cover:

CoolSys's training plans
First lessons for refrigeration and HVAC trainees
Keep It Simple, Stupid (KISS) in training
New technologies and energy efficiency in CoolSys training
Reading and independent learning
The ever-changing nature of the HVAC/R trade
Mentorship
Practical skills and training
CoolSys technical library

Check out CoolSys at https://coolsys.com/ to learn about the company and some job opportunities. You can also email Brett at bwetzel@coolsys.com or listen to the Advanced Refrigeration Podcast (YouTube channel: https://www.youtube.com/@advancedrefrigerationpodca9389).

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Oil Talk - Short #167 Jun 27, 2023

In this short podcast episode, Bryan gets into some oil talk, covering some common refrigerant oil terms and types.

Esterification is the process by which organic acid and alcohol come together to form polyolester (POE) oil and water. Hydrolysis refers to the decomposition of a substance when it comes into contact with water; when POE mixes with water, it will break down into esters, organic acids, and alcohol. Once POE oil undergoes hydrolysis, the process can't be reversed to get the same original oil.

POE oil is also hygroscopic; hygroscopicity refers to the ability of the oil to absorb moisture. Miscibility refers to the ability of an oil to mix with refrigerant and be carried with it. In the context of refrigerant oil, "polar" refers to a molecular structure with an uneven distribution of electrons; oils with polar structures attract water molecules. Solubility refers to how well one compound can dissolve into another.

Mineral oil is a product of the distillation of crude oil and was common in systems that used CFC and HCFC refrigerants. Mineral oil isn't as miscible with new refrigerants that lack a chlorine molecule. Alkylbenzene (AB) is a synthetic oil used in some commercial refrigeration systems that is compatible with mineral oil. Polyolester (POE) oil is one of the most common synthetic oils we use in systems that use HFC refrigerants; its main downside is its high hygroscopicity and tendency to undergo hydrolysis. Polyalkylene glycol (PAG) oil is common in automotive A/C systems (R-134A) and is more hygroscopic than POE oil but does not undergo hydrolysis. Polyvinyl ether (PVE) oil is used as an alternative to POE oil; it is more hygroscopic but does not undergo hydrolysis.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Megging a Scroll - Short #166 Jun 20, 2023

In this short podcast episode, Bryan talks about using a megohmmeter on a scroll compressor (or "megging" a scroll).

Scroll compressors are among the most common compressor types nowadays, and they come with their unique needs and best practices. You can't pump them down into vacuums (in many cases, you can't do that anyway due to internal protections), run them in a vacuum, or run a high-voltage megohmmeter or hipot test.

Scroll compressors differ from reciprocating compressors. A scroll compressor's motor is located at the bottom of the compressor, meaning it is immersed in refrigerant and oil when the system is operating AND when it is off; when the compressor is off and cold, there is a chance that there will be liquid refrigerant at the bottom. Compared to reciprocating compressors, scrolls tend to have a more compact and balanced design, and there could be a higher risk of internal arcing due to the tighter electrical tolerances associated with the design.

Many inexpensive megohmmeters will say that any measurement below 10-20 megohms indicates a short, but some scrolls will have acceptable readings as low as 0.5 megohms to ground; these readings will typically show up on the smaller kilohm scale. You must only use a megohmmeter to ground, not from winding to winding.

Moisture contamination, metallic debris, and lubrication issues can also cause a lower ohm reading than acceptable, so it's best to have historic data and track readings over time to make a diagnosis. Many modern multimeters can help you determine if a compressor is shorted to ground; you don't necessarily need a megohmmeter.

You may also read the following tech tip to learn more: https://hvacrschool.com/scroll-compressor-pump-down-megohm-test-fusite-plugs/

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Being an HVAC Creative Jun 15, 2023

Matt Bruner joins the podcast to talk about what it's really like being an HVAC creative. Matt is a young HVAC business owner who has recently written several HVAC School tech tips and pursued creative interests in the trade.

Being creative in any industry or aspect of life requires us to be aware of what's around us and think deeply about how things can be better. Creativity requires us to channel our dissatisfaction into finding a solution, not just complaining, similar to how children channel boredom into projects.

While the industry relies on processes and procedures to establish consistent standards, an over-reliance on processes can remove opportunities for HVAC professionals to be creative in their careers. However, creative solutions still need to be based on a solid understanding of the scientific and safety fundamentals of the trade. In many cases, processes get better when people are allowed to be creative and tweak existing models and ways of doing.

There is plenty of room for creativity in the design and installation of residential HVAC systems. Common problems, including the need for dehumidification, require creative solutions from smart people in the trade. Solving these challenges is fun for creative-minded people, especially those who acknowledge that they don't have all the answers. The HVAC industry has so many jobs that require creativity through hands-on problem-solving.

Matt and Bryan also discuss:

How Matt ended up in the HVAC industry
"Poor" creativity
Institutional and self-imposed constraints
AI and data models
What it really means to "do things better"
Unteaching and unlearning bad habits
Asking the right questions
Self-awareness
The evolution of "the right way" of doing things

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

EER, SEER and TXVs - Short #165 Jun 13, 2023

In this short podcast episode, Bryan talks about TXVs and their impacts on energy efficiency ratings (EER and SEER).

EER (Energy Efficiency Ratio) is calculated based on fixed conditions (an outdoor temperature of 95 degrees Fahrenheit and an inside temperature of 80 degrees with 50% RH). EER is a ratio of cooling-only capacity in BTUs per hour to the total electrical input in watts. SEER (Seasonal Energy Efficiency Ratio) is the ratio of an HVAC system's cooling output during a typical cooling season to the seasonal electrical input in watts.

Both energy efficiency ratios use non-proportional units (BTUs to watts), but SEER is supposed to account for a wide set of conditions (even though the climates of regional markets can vary quite wildly). EER2 and SEER2 are new standards based on updated equipment testing protocols with more realistic static pressures.

TXVs and EEVs can modulate to control the amount of refrigerant going into the evaporator coil. TXVs maintain a set superheat at the evaporator coil outlet, which it detects with a sensing bulb mounted to the suction line. These sorts of modulating metering devices can boost system efficiency by adjusting the amount of refrigerant it feeds into the evaporator coil. Underfeeding can lead to inefficiency, and overfeeding can cause system damage.

Non-bleed TXVs shut tight once the compressor shuts off, which prevents refrigerant migration during the off cycle and pressure equalization, thus protecting the compressor and reducing the cyclic degradation coefficient. The compressor may have to start a little bit harder, but the effects of the hard shutoff can improve the SEER rating by about 0.5. TXV systems are, overall, more efficient than systems fixed-orifice metering devices.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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High Performance Maintenance w/ Jim Ball Jun 08, 2023

Jim Ball from NCI joins the podcast to talk about high-performance maintenance contracts and agreements.

A high-performance maintenance agreement requires you to take system measurements and present solutions to maximize performance accordingly and exceed customers' expectations, not just make assumptions about the performance parameters. Key measurements we should know include the charge levels, total external static pressure, filter & coil pressure drop, and CFM per ton.

Many HVAC contractors and technicians don't really believe in maintenance procedures; some contractors merely want to keep customers or secure work during the shoulder months and don't aim to optimize the homeowners' systems. Maintenance procedures provide technicians and contractors the opportunity to improve the health and comfort of their customers. To perform a quality maintenance procedure, we need to establish company-wide processes that produce consistent results. When we standardize maintenance and installation procedures, we want to think about what an ideal system would look like and make our processes meet those expectations.

Scheduling is an important aspect of maintenance agreements, and your ability to commit to a schedule can make or break your maintenance program. Pricing is also critical, and customers tend to be educated on their options; many of them understand that a higher price will often indicate higher standards. As we perfect our maintenance procedures and take advantage of technology, we can embrace monitoring in our maintenance programs.

Jim and Bryan also discuss:

Jim's history in the industry
SEER ratings vs. real efficiency
The value of historical measurements
Craftsmanship and quality standards
"Unteaching" poor practices
Communication practices with customers
Roleplay as a training tool
Monitoring as the next step for high-performance maintenance programs

Learn more about NCI and high-performance HVAC at https://nationalcomfortinstitute.com/. You can email Jim at jimb@ncihvac.com or call him at (440)-670-8783.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Steve Coscia - HVAC Soft Skill Training Resources Jun 06, 2023

This episode of the HVAC School podcast Steve Coscia's symposium presentation: HVAC Soft Skill Training Resources.

Likability is a superpower in any job that requires you to interface with customers or students. Every word and mannerism your customer or student sees will matter, and it's important to be likable. Those impressions can heavily influence their decision-making.

Making a good first impression is one of the most important areas where we can focus our soft skills, and being on time is an easy way to make a good first impression on customers. When we are pleasant and convey mastery of our craft, we become more likely to earn appreciation and respect from customers and fellow tradespeople.

Delegating the authority of the class is a soft skill that is important for instructors, as it encourages participation and lets a student be recognized by their peers. Telling a "signature" story, using props, and making the classroom interactive also help you convey useful information to your students and keep them interested. The objective is to get students to talk, and applying the "rule of 10" with these methods should help keep students' attention. Whether you're leading an employee meeting or training a class, don't be afraid to embrace your unique brand of teaching or leadership.

Steve also covers:

Lessons learned as a writer and instructor
"Overpreparation"
Humility
Using action-oriented language and being honest
Cleanliness and organization skills
Sharing information with coworkers
The Silo Effect
Editorializing and saying too much
Using proper grammar and positive words
Congruency
Integrity, self-control, and proactivity
Buying time and convenience-oriented customers

Learn more about Steve's training at https://www.coscia.com/, and be sure to check out his training series on ESCO Institute's HVACR Learning Network at https://hvacr.elearn.network/pages/coscia-communications.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

I Installed an A2L and Lived to Tell About It! Jun 01, 2023

Roman Baugh returns to the podcast to talk about the time he installed an A2L system and lived to tell the tale.

Roman used most of his same R-410A tools to install the first A2L-based ductless mini-split in Florida. Flare blocks, wrenches, and torque wrenches will all stay the same; you just have to be sure that your vacuum pumps and recovery machines are rated for use on A2L refrigerants. A2L-based mini-splits use flared fittings with no brazing necessary; this is currently the A1 status quo.

Purging and flowing with nitrogen will be required of A2L systems. Purging refers to a higher flow rate and flowing refers to a very low flow rate (2-5 standard cubic feet per hour). If a pipe may have refrigerant inside of it, we will need to cut the pipe with a copper cutter, not use a torch.

You will need to store A2L refrigerant tanks upright and locked in your van. You'll want the tanks to avoid being banged around or struck by other objects in the van. Although A2Ls are non-toxic, they still displace oxygen if a valve opens.

Bryan and Roman also discuss:

"Mildly" or "slightly" flammable
Purging vs. flowing nitrogen
Deep evacuation
Flammable substances in the automotive industry
Will there be reverse-threaded connections?
The ever-changing HVAC industry
Lower charge amounts

Resources:

You can learn more about A2L refrigerants in general on the ESCO Institute e-learning network by checking out training courses at https://hvacr.elearn.network/.

Check out Opteon's new A2L refrigerant, XL41 (R-454B), at https://hvacrschool.com/xl41.

You can find Daikin's R-32 resources at https://www.r32reasons.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Motor Speed - Short #164 May 30, 2023

In this short podcast episode, Bryan talks about motor speed and other basic electrical topics as they relate to motors in HVAC equipment.

In a typical single-phase PSC-type (induction-driven) motor, the speed is primarily determined by the electrical cycle rate, also known as the hertz. The hertz represents the speed at which the electrical current changes direction (positive to negative) per second; in the USA, that number is typically 60 hertz. Unless we're dealing with ECMs and VFD-driven motors, the motor speed will be partially influenced by the hertz or frequency as determined by the utility company or a generator.

Motor speed is also determined by the number of magnetic poles in the motor. A motor doesn't make a complete revolution per cycle; a cycle only refers to the distance between two poles. The more poles we have, the shorter the distance needs to turn per cycle. A two-pole motor rotates all the way every cycle, resulting in 3600 RPM under no-slip conditions (synchronous speed). A four-pole motor has half the RPM, and an eight-pole motor has 1/4 of the RPM of a two-pole motor.

Speed taps add winding resistance between run and common to create slip and slow the motor. A six-pole motor has 1200 RPM synchronous, but 1075 is the effective speed with slip factored in. Each speed has a different level of winding resistance, which slows the motor as you move from high to low; the lower-speed tap has higher resistance than high-speed taps.

ECMs and VFD-driven systems convert the frequency and don't depend on the electrical frequency from the utility or generator.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Growing in Productivity and Confidence as a Tech w/ Refrigeration Mentor May 25, 2023

Trevor Matthews returns to the podcast to talk about growing in productivity and confidence as a tech to avoid feeling stuck in your career. They talk about personal development within your organization and in communities or training courses beyond your organization.

Confidence and productivity work hand in hand, and techs can grow in both areas when they prioritize the one that matters most to them. In many cases, repetition helps build confidence, especially in the trades and other professions where you work with your hands. Scheduling is another strategy that improves your productivity, which can boost your confidence in the long run.

As humans, we tend to fixate on fears and problems. We can build our confidence by reframing our fears, giving ourselves (and others) grace when we make errors, and focusing on building our skills to work through challenges. It's also important to find people in your organization who will uplift you, not hold you back.

Developing unhealthy habits is a possible consequence of over-focusing on work, and it could be detrimental to your personal and professional life. Your physical and mental health are also important to your productivity and progress.

Trevor and Bryan also discuss:

Using a calendar to manage productivity
Learning new skills to build confidence
Communicating with your employer and building a relationship
Training programs
Self-assessment and going out of your comfort zone
Caring about yourself to care about others

Some of Bryan and Trevor's favorite books on the topic:

Check out Trevor's Refrigeration Mentor program at https://refrigerationmentor.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

The Art of Unteaching w/ MeanHVAC May 18, 2023

This podcast episode is Alex Meaney's 2023 HVACR Training Symposium session: "The Art of Unteaching."

We may have flawed understandings of HVAC concepts, including the understanding that "heat rises." Our world is constantly shaped by the things we see and believe, and we are hard-wired to defend our observations and beliefs if we feel that those are threatened by new information. Instructors need to be sneaky about "unteaching" flawed ways of understanding the scientific principles of HVAC.

When we communicate concepts to others, we need to watch our language and make sure our messages are clear; the subtext is as important, if not more important, than the actual material. Humility also goes a long way when teaching, though teachers need to be especially careful of imposter syndrome.

Teachers can be most effective when they find a point of common ground between what their students already know and what they want to teach their students; avoiding jargon is a good way to make sure everyone can start on the same page before you teach them the vocabulary. When teaching, think about filling in the gaps without students realizing that those gaps have been filled; some teaching techniques, like inversion, can help with this process. Group settings also make it easier for students to process new information.

Alex also covers:

Pitfalls of the 12,000-BTU rule
Bridge vs. bedrock foundation
Pedantism and cognitive dissonance
Repeating and rephrasing answers
The "forgot to know it" approach
Humility and the "reset button"
Fallacies and heuristics
Being able to understand when you're wrong

Check out Alex's design consultation work at https://www.meanhvac.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Floating vs. Fixed Suction and Head - Short #163 May 16, 2023

In this short podcast episode, Bryan talks about compression ratio and efficiency, particularly how floating or fixed suction and head pressure affect those things.

Compression ratio (absolute head pressure divided by absolute suction pressure) closely correlates to efficiency in all sorts of compression-refrigeration HVAC/R systems; the most efficient systems have high mass flow with less compressor work. High compression ratios indicate a greater differential between the head and suction pressures. A lower compression ratio is desirable, but the number has to be realistic; a compression ratio of 1 indicates that the system is off. Medium-temp refrigeration compression ratios are typically around 3:1, whereas low-temp refrigeration can have higher compression ratios (6:1).

In commercial refrigeration applications, we can help control the compression ratio with floating suction and head strategies. Floating the suction and head pressures allow the equipment to achieve lower compression ratios and higher equipment efficiency. Old strategies for controlling compression ratio would involve having a fixed evaporator temperature and suction pressure. In a parallel rack system, floating suction allows the suction pressure to float up when the case maintains temperature; this strategy helps close the gap between the absolute suction and absolute head pressures and reduces the compression ratio.

Floating suction strategies allow the suction to "float" up by allowing the evaporator coil temperature to rise a little bit when the box temperature is under control. Floating head strategies, on the other hand, allow the head pressure to float down in low-ambient conditions. We can look at ambient temperature and discharge pressure to determine how much we can float down the head pressure.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Humidity Utopia w/ Nikki & Bryan May 11, 2023

This podcast episode is Nikki Krueger (Santa Fe Dehumidifiers) and Bryan's 2023 HVACR Training Symposium session about how we can optimize dehumidification and efficiency to create an HVAC design and humidity utopia.

While we attempt to achieve comfort and high indoor air quality in humid climates, we may find challenges integrating these with the HVAC system and getting customers to understand the need for proper dehumidification. Older homes that are built "leaky" allow for uncontrolled infiltration and exfiltration, but newer constructions are a lot tighter and rely on mechanical ventilation to control where the outdoor air comes from and make sure it is properly filtered and distributed.

We deal with both sensible and latent BTUs in a home, and we can't treat them as though they're all equal. Many high-efficiency systems have high sensible heat ratios (SHRs) and are designed to remove sensible BTUs very efficiently, but they're not adequate at removing latent BTUs. Ideally, we would rely on an A/C system or heat pump to dehumidify the air in cooling mode before adding a dehumidifier. However, some of the systems that are best equipped to handle high latent loads will be less efficient.

If you wish to install supplemental humidification, the ideal design will have a dedicated return and tie into the main HVAC supply duct.

Nikki and Bryan also discuss:

Willis Carrier's real invention
Strategies for reducing conductive, convective, and radiant gains
Understanding relative humidity and dew point
Design loads
Electrification and energy efficiency incentives
Adiabatic heating and cooling
Single-stage vs. multi-stage equipment
Dehumidification for ductless mini-splits
Supplemental dehumidifier designs

Learn more about Santa Fe Dehumidifiers at https://www.santa-fe-products.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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What the Flux? - Short #162 May 09, 2023

This is the episode for you if you've ever asked, "What the flux?" In this short podcast, Bryan explains the basics of flux in soldering and brazing, as well as magnetism.

Flux means "flow." In HVAC, "flux" may have two meanings. It may refer to the substance that helps the molten alloy flow and bond to base metals more effectively when you're soldering or brazing. However, flux may also refer to magnetic flux, which is the lines of force that emanate from a magnet; this concept is important in inductive loads like transformers.

In soldering, brazing, and welding, flux is a powder-paste or liquid that you apply to the base metal. You usually apply it directly to the male side of the base metal, or it may be embedded in the brazing alloy. Flux prevents oxides (like rust or the black flakes, cupric oxide) from forming on the surface you're brazing, which commonly happens at higher temperatures. Flux helps you create a proper bond, but it doesn't eliminate the need to clean the base metal before brazing.

You typically don't need flux when you use silver-phosphorus or phosphorus-copper brazing rods for copper-to-copper brazing; the phosphorus acts as a fluxing agent, and using flux may increase the risk of contamination. It's also important to remove the flux from the metal after brazing because it may cause pitting; you may use a brush and/or a wet rag.

Flux is useful when you use rods with high silver content or when you have other base metals; the appropriate flux will depend on the base metal, especially if you're soldering aluminum.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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The Impacts of Duct Leakage w/ Steve Rogers May 04, 2023

Steve Rogers from The Energy Conservatory (TEC) returns to the podcast to discuss the impacts of duct leakage on occupant comfort and HVAC system performance.

Duct leakage has more significant negative effects in heat pump systems than in furnace systems, especially in climates with high heating, cooling, or latent loads, due to pressure imbalances and moisture problems. You can measure duct leakage by masking off all supply and return registers, attaching a calibrated fan, and running the duct blaster to pressurize the duct work to 25 Pascals.

Exhaust-only ventilation presents many of the same problems as duct leakage, particularly in the humid South. The duct leakage allowable by code (in Florida) is almost equivalent to a 50-CFM bathroom fan.

Leakage often happens on the supply side, and it is important to determine whether the leakage is happening on the supply or return side; you may lose significant capacity on the supply side, and you may lose a little less capacity if the leakage is primarily on the return side. That capacity, however, is often heavily latent, leading to potential moisture problems (though less so in cold climates). Duct leakage may go outside or merely into an unconditioned space within the home; you can test the duct leakage outside with a duct blaster and a blower door simultaneously.

Steve and Bryan also discuss:

Duct leakage problem differences in the North and South
Regulations and their effects on changeout practices
Using powered flow hoods and a TrueFlow grid to measure duct leakage
Duct leakage allowable by code
Home construction types and duct configuration
Envelope leakage
Leakage testing and pricing
Low-Income Heating Assistance Program (LIHEAP)

Learn more about TEC at https://energyconservatory.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Launch of the Sensi Touch 2 Thermostat May 02, 2023

Tom Lorenz from Sensi joins the podcast to talk about the launch of the Sensi Touch 2 thermostat. The Sensi Touch 2 smart thermostat is compatible with room sensors, which makes it an efficient and effective thermostat.

Smart thermostats are becoming more common in homes, especially as we focus on HVAC efficiency. Designers are aiming to make smart thermostats user-friendly, aesthetically pleasing, easy to install, and driven by data (via sensors).

Installation is easy for contractors, as it relies on push terminals and cleanly covers up the previous thermostat's installation site. The Sensi Touch 2 requires a common wire, but it has easy-to-use push terminals that allow wires to click into place. It also has dedicated accessory terminals for add-on equipment like dehumidifiers. You can also pair the Sensi Touch 2 with its respective app to program the thermostat.

Smart maintenance automatically alerts homeowners about poor performance or efficiency. These sorts of alerts can offer peace of mind for the homeowner. The room sensors allow the Sensi Touch 2 to manage home comfort by collecting data from several locations of the house; you can sync up to 15 room sensors to the Sensi Touch 2 thermostat.

As with other Sensi thermostats, the Sensi Touch 2 has contractor branding capabilities. You can get your company name and number programmed into the main display so that the customers know who to call whenever they need something. You can learn more at procontractorbranding.com.

Tom and Bryan also discuss:

History of Emerson, White-Rodgers, and Sensi controls
Personal data and privacy concerns with smart technology
Smart thermostat design and aesthetics
Energy Star certification
Sensi Lite (coming soon)
Warranty information

Learn more about the Sensi Touch 2 at https://sensi.copeland.com/en-us/for-professionals/touch2-smart-thermostat.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Why and How to Create an Internal Training Program W/ Eugene S. Apr 27, 2023

Eugene Silberstein from ESCO Group returns to the podcast to discuss why and how to create an internal training program for your HVAC/R company.

HVAC/R has so many niches, and information and practices are always evolving, so lifelong learning is necessary for the industry. In-house training is a form of education that can come with many benefits, including control over scheduling, building community within the organization, and convenience. However, creating an in-house training program also comes with many challenges, including time and money expenses.

For an internal training program to work, there needs to be a clear commitment to lifelong education that is ingrained in the culture. That could include bringing in other educators, setting up mentorship programs, and partnering with local trade schools. Unlike an external training program, an in-house training program also allows you to tailor education to your technicians' goals and needs.

A good in-house training program creates an environment of psychological safety; it allows trainees to ask questions without feeling singled out or judged. Some people who know topics well aren't the best trainers; trainers need to know how to teach others, which means understanding how the human mind works.

Commitment is ultimately what makes or breaks an internal training program. If your trainees can see that you are investing in them consistently, they will be more likely to give and get the most out of the training program.

Eugene and Bryan also discuss:

The hunger and need for HVAC/R education
Benefits and drawbacks of external training
Using mistakes and callbacks as learning experiences
Educators who make trainees feel safe
Education, engagement, and entertainment
Will technicians leave your company if you train them?
Casual but deliberate training

Learn more about ESCO Group's HVACR learning network at https://hvacr.elearn.network/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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When Subcooling is Meaningless - Short #161 Apr 25, 2023

In this short podcast, Bryan talks about the times when subcooling is meaningless. It is important to understand subcooling fully before using it as a charging or diagnostic method, particularly in refrigeration systems.

When we need to charge TXV systems in residential HVAC, many technicians rely on subcooling to set the charge. However, refrigeration systems don't quite work the same way; charging a refrigeration system by subcooling may lead you to overcharge the system.

We take subcooling on the liquid line between the condenser and the metering device. The condenser takes superheated vapor and rejects heat. This process turns the superheated vapor refrigerant into a liquid-vapor mixture midway through and subcools the liquid refrigerant at the bottom of the condenser. That liquid "stacks" at the bottom of the condenser. Adding more refrigerant will cause more liquid refrigerant to stack up at the end of the condenser and increase subcooling. These conditions can cause an increase in head pressure.

However, many refrigeration systems have receivers between the metering device and the condenser. Excess refrigerant gets stored in the receiver; it doesn't stack up in the condenser, and it doesn't contribute to additional subcooling. As the liquid line fills and the metering device restricts, the liquid goes into the receiver, not the condenser. Subcooling won't change much until the receiver is full, which is a major problem; receivers should only be up to 80% full, even when pumped down. So, we rely on sight glasses or receiver-level monitors to determine the charge, not subcooling. The goal is to keep the sight glass clear, meaning there is a full line of liquid going to the metering device. (However, sight glasses will also be clear when the system is off or empty.)

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Solving Work Life Imbalance w/ Craig M Apr 20, 2023

Craig M (AC Service Tech) returns to the podcast to talk about solving work-life imbalance, especially for HVAC/R technicians who have children and families of their own.

Our actions tend to be driven by our priorities, which vary at different stages of our lives. Someone's work-life balance could also vary depending on different parts of the year. When we let the right people into our lives and are surrounded by supportive communities, we can reconfigure our personal and career trajectories to keep them in line with our priorities. To create a healthy work-life balance, we must be open to investing in others and letting others invest in us.

"Balance" implies a constant state of evenness, but for people who work many hours, own a business, or have a family, their time may not be perfectly balanced at all times. That sort of variety presents a challenge, but it also presents opportunities for us to invite wise counsel and maintain communication to make sure we're on the same page as the important people in our lives.

We are imperfect, and in many cases, we make mistakes when we do things we shouldn't do or fail to do things we should do. When we make those mistakes or bad things happen, we can think about practical measures we can immediately implement in our lives to make them more fulfilling in terms of our long-term vision.

Craig and Bryan also discuss:

Providing for one's family
Seeking counsel and wisdom from others
How lifestyles and priorities shift as children grow up
Intentionality and short-term vs. long-term thinking
Making the "right" decision
Letting people struggle but supporting them
Emotional maturity
Authenticity
Bringing positivity to communication and relationships

Learn more about Craig's books and other educational resources at https://www.acservicetech.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

ROT Can Cause Duct Issues - Short #160 Apr 18, 2023

In this short podcast, Bryan explains how rules of thumb (ROT) can cause duct issues. He talks about the role of friction rate in duct design as well as its intent and limitations.

Friction rate is a value located on duct calculation tools, including Ductulators. We use friction rate to predict the operating static pressure of the system, but it is often misapplied when people design their ductwork around rules of thumb. The friction rate is expressed in inches of water column ("WC), which we also use to measure static pressure. However, the operational static pressure and friction rate are NOT the same things.

Ductulators provide information about friction rate based on 100 feet of straight ductwork in the size selected, which we almost never see in the field; fittings and turns add effective length (EL), so the total effective length (TEL) is often more than 100 feet. When duct designers apply rules of thumb, like a 0.1" friction rate, and apply it to the CFM, they don't consider the actual length of the duct. So, the ducts are often undersized and don't properly account for the actual resistance to airflow.

If you want to stop using rules of thumb, ACCA Manual D and related software can help you get more precise design parameters and account for other restrictions.

The following tech tips contain more information and specific equations to help you find the total effective length: The Friction Rate Chart (and What it Means), What the Heck is a Friction Rate? (Eric Kaiser), How to Determine the Friction Rate for Residential Duct Design (Neil Comparetto).

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Heart of a Teacher w/ Craig M. Apr 13, 2023

Craig Migliaccio (AC Service Tech) returns to the podcast to talk about what it means to have the heart of a teacher.

Craig discovered his passion for teaching while instructing apprentices on the job, and he went into institutionalized teaching from there. He chose to overcome several administrative obstacles to become eligible as a teacher at technical schools, and that perseverance is one aspect of the "heart of a teacher."

One of the most rewarding aspects of teaching is the investment in others. For Craig, HVAC is a tool for supporting someone's family, and a teacher can find a sense of purpose in helping people be better HVAC practitioners. When good teachers invest in their students or apprentices, they give those people a reason to take pride in their work.

The job of a teacher isn't to give students the answer, which can be frustrating for students and the teachers of those frustrated students. People who have the heart of a teacher allow students to learn things themselves and be frustrated when they don't receive the answer immediately. Teachers ultimately care and want to keep improving, and they get their students to ask questions. The most important aspect of teaching is getting students to retain knowledge and build on it, and many students retain knowledge when they get to ask questions on their own and apply their knowledge.

Craig and Bryan also discuss:

Craig's experience with teaching licensure
The intrinsic desire to share knowledge or skills
Investing in others during a labor shortage
Switching mindsets
Monologuing vs. asking questions
Continuous improvement as a teacher
Impostor syndrome and teaching
Making educational content more valuable
Limitations of video/audio education

Learn more about Craig's books and other educational resources at https://www.acservicetech.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Saturation can be CONFUSING - Short #159 Apr 11, 2023

In this short podcast episode, Bryan explains why saturation can be CONFUSING and clears up some common misconceptions.

Saturation applies to dehumidification and refrigerant inside the system. Generally, saturation is the state at which a substance can no longer hold or absorb any more of another substance. When air is saturated with water vapor and can hold no more, it is at the dew point or 100% relative humidity; it will condense on any surface below the air temperature.

Air isn't like a sponge that absorbs water vapor; saturation deals with vapor pressure, particularly the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases in a closed system.

Dehumidification is the process by which we remove moisture from the air; this process improves comfort across a significant portion of North America during the summer months, and it prevents fungal growth inside the home. Air in a dehumidifier or an HVAC system in cool mode makes contact with a surface at a temperature below the dew point. So, moisture comes out of the air and condenses on the coil. Colder evaporator coils, which result from longer runtimes, are more effective at removing moisture.

Inside a system, the refrigerant in the evaporator boils as it absorbs heat. The refrigerant can absorb a lot of heat due to the heat required to change state, also known as latent heat (compared to sensible heat, which is the heat required to raise the temperature of a substance). Until the refrigerant completely boils off, it is at saturation. Pressure also dictates the saturation point, and we use refrigerants that can boil under the appropriate temperature and pressure conditions for the HVAC equipment we're working with.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Working on Ventilation in Humid Climates w/ HAVEN Mar 30, 2023

Kevin Hart from HAVEN returns to the podcast to talk about ventilation in humid climates and some best practices for working on systems that focus on the V in HVAC. HAVEN focuses on IAQ management with the use of software technology.

HAVEN started off with its central air monitor, and the company then developed a central air controller to help customers make their homes healthier. Fresh-air ventilation is one IAQ, but humid climates make it tricky to bring that air in; dumping “fresh” air into the structure without taking extra precautions can lead to high indoor humidity and even microbial growth.

ERVs, HRVs, and ventilating dehumidifiers are some traditional ventilation strategies for various climates; exhaust ventilation is also quite common but can pull hot, humid air through the building envelope. HAVEN is creating a more templated approach to ventilation; HAVEN uses whole-home in-duct monitoring and local weather data to get ideas of the conditions inside and outside the home to tailor fresh-air ventilation to each individual system’s needs.

HAVEN has partnered with several ventilating dehumidifier manufacturers, including Santa Fe and AprilAire; many of these manufacturers also use filtration to control the quality of incoming fresh air.

Kevin and Bryan also discuss:

HAVEN’s journey during the COVID-19 pandemic
Chemical interactions in our homes (VOCs and CO2)
Exfiltration and infiltration
The problem with industry standards and regulations
Appropriate climates for ERVs, HRVs, and ventilating dehumidifiers
Using dew point to control indoor and outdoor parameters
Energy savings with HAVEN’s technology
Does a house need to “breathe?”
HAVEN app

You can learn more about HAVEN’s offerings for HVAC professionals at https://pro.haveniaq.com/ and get a discount on HAVEN’s product bundle at https://www.trutechtools.com/ by using the coupon code haven2022.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Check out our handy calculators HERE.

HVAC Performance Summit w/ Dominick G. Mar 23, 2023

Dominick Guarino from NCI joins the podcast to talk about the High-Performance HVAC Summit, an upcoming event hosted by NCI from April 17–20. The National Comfort Institute (NCI) is a training organization that helps technicians learn crucial skills and succeed through high-performance contracting.

High-performance contracting is based on the mindset of “don’t just promise performance; prove it.” To maximize technicians’ potential, NCI teaches technicians how to test equipment properly and monetize their skills. Techs can then use their knowledge to teach the homeowner about the system and solve problems with sales; they can earn money while being solutions-oriented.

NCI’s High-Performance HVAC Summit is a training event geared toward HVAC business owners and contractors. It started as a membership conference for education and networking, and it has since expanded to include like-minded HVAC professionals from all walks of life. Workshops are led by a mix of contractors and NCI staff, and there are breakout sessions and other various session types.

This year’s High-Performance Summit theme will be “It All Starts With Service.” The four focal points of the workshops will be lead generation through service and maintenance, CO safety, the lead handoff from service to sales, and maintenance agreements. One more session will focus on hands-on testing, called “Low-Performance Town” this year, and there will be a panel about the future of high-performance HVAC.

Dominick and Bryan also discuss:

Dominick and NCI’s history in the industry
High-performance maintenance
Consumers who do their research
The HVACR Training Symposium
High-Performance Summit Awards Banquet
NCI’s collaboration with other industry leaders and organizations

Visit https://www.gotosummit.com/ to learn more about the High-Performance Summit. If you decide to register for the summit, type HVACSCHOOL in the coupon code section for a $100 discount.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Training, Combustion and More w/ Tony G. Mar 14, 2023

In this podcast from AHR 2023, Tony Gonzalez from Fieldpiece joins Bryan to talk about training, combustion, and more.

Fieldpiece has a new combustion analyzer that reduces the cost of tool ownership and maximizes the tool's uptime, namely by using a long-lasting sensor. The combustion analyzer's oxygen and CO sensors seal up when the combustion analyzer is turned off, which pauses degradation. The sensors are also field-replaceable and come with a 4-year warranty. The CAT85 also has a built-in dual-port manometer (which can measure static pressure) and can measure a live draft pressure during combustion analysis.

Some common misconceptions exist around combustion analyzer sensor lifespans and calibration. The sensor life refers to how long a sensor can output a signal to generate a reading; it doesn't refer to the accuracy of the sensor at the end of its life. Calibration keeps the sensors accurate, especially because sensor accuracy tends to degrade over time. To get the most out of your sensor, yearly calibration is recommended.

Fieldpiece is also launching its ambassador program, which is a network of independent trainers with field knowledge who have been trained to become Fieldpiece product experts. Those ambassadors then train contractors and technicians on behalf of Fieldpiece.

Tony and Bryan also discuss:

Fieldpiece's sensor calibration process
Water freezing in combustion analyzer traps
Distinguishing your company from the competition with superior tools
Technical training from Fieldpiece
Fieldpiece leak detectors and new A2L refrigerants
Infrared vs. heated diode leak detector sensors

Learn more about Fieldpiece tools at https://www.fieldpiece.com/ or ask about training by emailing training@fieldpiece.com.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

The Future of Refrigerants is Here With Opteon XL41 Mar 09, 2023

In this podcast from AHR 2023, Brandon Marshall from Chemours and Chris Forth from JCI talk about the future of refrigerants and Opteon XL41 (R-454B).

Refrigerant regulations are changing to pave the way for lower-GWP refrigerants, but M1 is also in full swing. M1 refers to the U.S. Department of Energy's implementation of the new efficiency standards for A/C units and heat pumps (SEER2, EER2, etc.). These standards changed the equipment testing procedure to match field conditions more closely.

Opteon is the next-generation portfolio of low-GWP refrigerants for Chemours as a successor to the legacy refrigerants in the Freon product line. These refrigerants are a response to the HFC phasedown outlined in the AIM Act. JCI chose to use Opteon XL41, an HFO, for its equipment due to Opteon XL41's low GWP compared to R-32 and because of the similar operating pressures and temperatures to R-410A.

A2Ls are a permanent change in the industry, and their safety considerations and best practices are here to stay. However, even though A2Ls are more flammable than A1 refrigerants, they are nowhere near as flammable as A3 refrigerants. Just about any refrigerant can propagate flame under the right conditions (including A1s), so A2Ls are only a little bit more flammable than those.

Brandon, Chris, and Bryan also discuss:

Brandon and Chris's industry experience
The transition from CFCs to HCFCs to HFCs
Refrigerant reclamation
Upcoming GWP limits
Hydrofluoroolefins (HFOs)
A2L refrigerant product testing
Staying up to date on A2L training resources
Some of the prominent flammable refrigerant trainers
Smuggled and counterfeit refrigerants

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Check out our handy calculators HERE.

MeasureQuick is EXPLODING with Jim & Joe Mar 07, 2023

In this podcast from AHR 2023, Jim Bergmann and Joe Medosch talk about measureQuick and the ways it's EXPLODING with growth and new features. They also talk about heat pumps, electrification, and other hot topics in the industry.

Jim Bergmann recently released an open letter about heat pumps on LinkedIn; he addressed the shortcomings of the industry from a skill standpoint. The lack of training and standards may be mitigated with proper training (and an understanding of building science fundamentals) or by embracing hybrid systems. Heat pumps may also perform relatively poorly during extreme weather events and may not manage temperature swings well.

MeasureQuick has recently been working with ACCA and formed other partnerships to allow for standardization (for companies and the industry as a whole). More companies are also integrating with measureQuick, especially TEC and their TrueFlow Grid; accuracy across brands tends to be pretty consistent, and measureQuick allows you to mix and match tools. The customer-facing side of measureQuick has also received some development, which allows the customer to see the value and quality of their installation.

MeasureQuick is keeping up with the growing pains by doing constant testing. Joe and Jim make sure the user experience is seamless, intuitive, and free of problems or inconveniences.

Jim, Joe, and Bryan also discuss:

Fixing the building envelope
Heat pump vs. gas furnace comfort
Energy Star certification for installations
measureQuick user base milestones
Industry leaders, supporters, and partnerships
New measureQuick workflows
Joe Medosch's role at measureQuick
The challenges of the HVAC trade
Technology challenges for measureQuick's users
Free and paid measureQuick features

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Infiltration Skeletons Behind Closed Doors w/ Genry Mar 02, 2023

Genry Garcia returns to the podcast to talk about pressures in the building envelope, namely the infiltration skeletons behind closed doors.

When doing load calculations (Manual J), we need to know how much of the heat load, especially the latent heat load, comes from leakage in the building envelope and the ducts. Opening/closing doors and windows can also worsen the issues that stem from infiltration due to upsetting the balance of pressures in the home. Smoke pencils and other similar tools can give you an idea of the pressure in a home and how it could change when doors open or close.

Since there is a lot of room for inaccuracy in extreme climates (especially those with high latent loads), many HVAC systems are oversized and underperform. Some building design features also exacerbate problems presented by oversized HVAC systems. To get the data we need to design systems that mitigate those issues, we need to do a blower door test.

Downsizing the tonnage in retrofits or replacements usually has advantages, but it must be done right, and customers may not always want to do that. It's the contractor's responsibility to give them a choice and educate them about the options and what the thorough diagnostic process looks like, including balancing the home and checking the pressure in relation to the outdoors.

Genry and Bryan also discuss:

Positive and negative pressure in certain rooms
Exhaust ventilation and pressurization
Using See Stack to see differences in loads
Leaving the fan in the "on" position
Useful tools
Variables in lab-based testing and field testing
Getting hung up on the 3 Pascals rule of thumb
Leaky rooms vs. whole-home leakage

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Understanding Leak Detectors With Inficon Feb 28, 2023

In this episode recorded live at AHR Expo 2023, Nick from INFICON joins Bryan to talk about leak detectors and how we can improve our understanding of them.

Some leak detectors, including the INFICON Stratus, measure concentrations in PPM (parts per million). When measuring PPM, we have to keep in mind that it doesn't indicate the size of the leak or leak rate, but it does help us pinpoint the leak location. In some cases, we also have to watch for automatic zeroing capabilities.

Leak detectors come in many varieties, including heated-diode, ultrasonic, and infrared; each type has unique maintenance needs. Heated-diode leak detectors are sensitive, but their sensors wear off with frequent use and will require replacement. Infrared leak detectors use infrared absorption and don't degrade over time the way heated-diode leak detectors do. An ultrasonic leak detector picks up the sound of refrigerant and air leaking out of a hole to pinpoint the leak.

It's a good idea to approach leak detection with a plan, including starting high on the coil and moving down (because refrigerant is heavier than air and may set off the leak detector below the actual leak). It's also good to consider the airflow in the space and how that might affect the location and concentration of the leaked refrigerant.

Nick and Bryan also discuss:

Pressure, hole shape, and leak rate
Understanding tool maintenance
Infrared leak detector usage and considerations
Common causes of leak detector failure
D-TEK product line
CO2 and hydrocarbon sensors for leak detectors
D-TEK Stratus modes (cloud hunting and pinpoint)
Applications for D-TEK Stratus leak detectors
"False" positives

Learn more about INFICON at https://www.inficon.com/.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Making Cold Climate Heat Pumps Work w/ Copeland and White Rodgers Feb 23, 2023

In this episode recorded live at AHR Expo 2023, Dustin and Jim from Copeland/White-Rodgers join Bryan to talk about the use of heat pumps in cold climates. They talk about the history of heat pump innovation and talk about changes to come.

Variable-speed and two-stage compressors, as well as advanced controls, make it easier for contractors to control sizing and for heat pumps to perform to acceptable standards in cooler climates. Contractors in cold climates also rely on dual-fuel models that use electric and gas heat, which makes it easier for the system to move the desired amount of heat.

Variable-speed and two-stage compressors help the system deal with different heating and cooling capacities; in cooling mode, these technologies can also help with latent removal if the blower is also able to vary with the compressor.

Advanced controls, especially universal controls, also help with defrost management, a key component of heat pump performance. When defrost is managed effectively, customers can yield energy savings. The White-Rodgers universal defrost control comes with coil and outdoor temperature sensors (thermistors) to determine when the unit is ice-bound; it also has a thermostat that can control second-stage heat.

Dustin, Jim, and Bryan also discuss:

Electrification and heat pump sales
Vapor injection and compression ratio control
Freq drives
White-Rodgers universality and nomenclature
Timed vs. demand defrost
Electric heat vs. gas/oil heat costs
WR Mobile app
Multi-volt contactors (White-Rodgers SureSwitch)
Pool heat pumps and contactors
Crankcase heaters, long line sets, and total system charge
A2L refrigerant testing

Learn more about White-Rodgers products on the WR Mobile app, our partner page at https://hvacrschool.com/partner/emerson-white-rodgers/, or the website at https://climate.emerson.com/en-us/brands/white-rodgers.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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RTU Retrofits Facts and Considerations with JCI Feb 21, 2023

In this episode recorded live at AHR Expo 2023, Matthew Schlegel, the Commercial Product Manager of Ducted Systems from JCI (Johnson Controls) joins Bryan to talk about rooftop unit (RTU) retrofit facts and considerations.

When doing an RTU retrofit, you want to make sure you know the budget before anything else; larger budgets will allow you to implement things like VFDs and even VAV technology. In many cases, you may consider adding an economizer for "free" cooling and energy savings. You also want to know what you will get out of a retrofit in terms of value, especially when it comes to system efficiency and longevity.

Some common IAQ upgrades for RTUs include improved filtration, especially with MERV 13 filters. Economizers also allow you to control the amount of outside air with the help of an exhaust system or even barometric relief. UV lighting can also be used in light commercial RTUs.

When doing a retrofit, you'll want to pay attention to the existing equipment's footprint. Sticking to that footprint will make the replacement aspect easier. The utility and electrical infrastructure are also important to consider, as you won't want to replace the existing piping, wiring, and connections.

With regulations and technology constantly changing, it helps to be able to contact the manufacturer to assist with the retrofit process. Companies like JCI are trying to assist contractors with installations by providing guidance and education in the field.

Matthew and Bryan also discuss:

Matthew's professional experience at JCI
Adding economizers and VFDs
Convertible filter racks
Cost-benefit analysis resources
Changing regulations
Interfacing with the manufacturer during the retrofitting process

To learn more about JCI, visit https://www.johnsoncontrols.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Troubleshooting The Modern ECM Feb 16, 2023

Chris Mohalley returns to the podcast to talk about troubleshooting the modern ECM (or EC motor) and give diagnostic tips. ECMs are electronically commutated motors; they are mechanical motors with an electronic control module that dictates everything the motor does.

As with all motors, ECMs have inputs and outputs. If the motor is not running, the first step is to check the line voltage and make sure that it is correct and connected continuously, as that's one of the main inputs on all ECMs; there is no relay or switch on the line side. The motor itself is the output, so you will know if the output is correct if the motor is rotating and generating airflow as intended. Constant-speed and constant-torque motors can all be diagnosed with a basic voltmeter.

One of the most difficult parts of troubleshooting constant-torque ECMs is knowing how the taps are programmed by the manufacturer; reading the manual and schematic is advantageous during diagnosis, especially as these motors have evolved to use pulse-width modulation (PWM) and have nine speeds instead of five (energizing pin 1 at the same time as another pin, diagnosed with 24v AC). Constant-airflow motors tend to have inputs that are less complicated than the five or nine-speed taps.

Chris and Bryan also discuss:

Inputs: line voltage and signals
TechMate Pro, multimeters, and Genteq TECINspect diagnostic tools
Constant-speed vs. constant-torque vs. constant-airflow motors
Diagnosing PWM signals with DC voltage
Adjusting airflow with DIP switches
Are board and motor failures common?
Why we don't diagnose the motor separately from the control

Learn more about Regal Rexnord's FREE training at https://regal.mmu.com.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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Training for the Future w/ Clifton & ESCO Feb 09, 2023

Clifton Beck of ESCO Group returns to the podcast to talk about training for the future. He also talks about how he became an educator, what it's like to be a trades educator with ESCO Group, and how educators can handle the recent HFC phasedown and the rise of A2L refrigerants.

Especially with the COVID-19 pandemic, mass media has changed the way the industry thinks about training. Organizations like ESCO have evolved, and that is evident in their curricula; changes are being made to keep up with field tools and equipment to make sure technicians are up to date. A large network of industry experts makes these training curricula possible.

Virtual and media education have changed the way we think of educators. Many of the most knowledgeable people in the industry, including people like Craig Migliaccio, work in the field and aren't traditional educators but have a large positive influence on the industry due to social media.

Refrigerant regulation changes, including the HFC phasedown, present opportunities for training to focus on combating misinformation and adapting to field conditions. Training should aim to eliminate confusion and anger in these situations. Proper installation and service procedures will make the A2L transition much easier.

Clifton and Bryan also discuss:

Clifton's professional history
HVAC experts and relationship building
ESCO Institute and HVAC Excellence
The evolution of educators and expectations for them
HFC phasedown facts
Recovery, recycling, and reclaiming refrigerant appropriately
Commercial vs. residential HVAC/R and refrigerant regulations
Educators as social media personalities
HVAC Excellence Conference

Learn more about ESCO Group's resources at https://www.escogroup.org/. You can also check out the ESCO Group YouTube channel at https://www.youtube.com/@escogroup.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

MERV vs. Motors Feb 07, 2023

ECM expert Chris Mohalley joins the podcast to talk about the balance between selecting air filtration and motor performance, also known as "MERV vs. Motors."

As the industry realizes that filtration is more important, we're starting to see an interest in filters with MERV ratings of 13 or higher. However, there are some design challenges associated with static pressure drops across filters, motor responses to static pressure, and airflow. If the airflow isn't set properly, that could affect the refrigerant charge and temperature rise.

PSC motors' performance directly follows the load; as static pressure increases, the airflow rate produced by the motor decreases. They may also make loud noises when the static pressure is high but satisfactory airflow. However, they are robust and don't typically fail quickly due to high static pressure.

Electrically commutated motors (ECMs) are operated by electronic controls and come in constant torque or constant airflow varieties. The former has a performance curve (like a PSC motor) but doesn't appear to suffer from longevity issues when the static pressure is high; the latter can adjust airflow based on static pressure, but it is likely to have issues maintaining airflow during high static pressure conditions. Regardless, there is still an operational envelope; going outside of that envelope will likely result in a capacity and/or efficiency hit if there is high static pressure.

Chris and Bryan also discuss:

COVID-19 pandemic and the evolution of filtration
Face velocity across filters
Amps in constant torque vs constant airflow motors
Swings in airflow/performance
Educating the customer about "upgrading" filters
Using performance manuals

Learn more about Regal Rexnord's training at https://regal.mmu.com.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Effective Filtration & More w/ John Ellis Feb 02, 2023

John Ellis, a business consultant who specializes in IAQ training, joins the podcast to talk about effective filtration, product development, and more. John has recently worked with an OEM to bring field practicality and application to the engineers who design products.

Filtration design is a relatively poorly understood concept in the industry; we tend to overlook a filter's ability to remove particulates from the air when we prioritize static pressure drop. We have to understand how the duct design can make higher-MERV filters work and how the face velocity plays into design and comfort.

John also talks about bypass HEPA filtration and its appropriate uses and potential for misapplication. Bypass HEPA may be integrated with the HVAC system (but run independently of the system) or installed independently of the HVAC; its effectiveness will be dictated by its runtime, and it doesn't filter everything.

IAQ products and strategies need to produce quantifiable results, and our industry needs people to be trained to measure and produce those results, not push products. Education, integrity, and competence are the keys to starting conversations about IAQ methodologies that actually benefit the customer.

When we're ready to have those conversations with the customer, we can show the customer that we prioritize their health, safety, and comfort; it's good to use maintenance procedures as times to follow up with the customer and make sure their IAQ needs are being met. Communication is critical here.

John and Bryan also discuss:

Design, production, and distribution
MERV ratings
Oversized filter-back returns with media filters
Blow-by
Charcoal carbon pellets vs. activated carbon
Oxidizers and microbiology disruption
Sales resistance & being pushed to make more sales
Problems with circuit boards

Learn more about John's work at https://thenewflatrate.com/ or contact him directly at (505)-652-8119.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Do Houses Need to Breathe? w/ Allison Bailes Jan 26, 2023

Dr. Allison Bailes from Energy Vanguard joins the podcast to answer the age-old question: do houses need to breathe? He also talks about his new book, A House Needs to Breathe... Or Does It? You can purchase that book directly through the Energy Vanguard site at https://energyvanguardstore.com/ or on Amazon.

HVAC professionals can benefit from learning about building science because there is a lot of overlap between the two, and an HVAC technician who knows about building science can set themselves apart in the market.

In short, Dr. Bailes doesn't think a house needs to "breathe," especially if a house brings in low-quality air, especially humid air, through gaps and cracks. Some people also use the term "breathe" differently; some may be referring to leakiness, and others may refer to drying out a house. It is necessary for a house to be dry, but we want to make sure that fresh air is controlled.

If you build a home tightly, you have to ventilate it correctly. We have to control air, liquid water, water vapor, and heat. Heat is especially complicated, as it has three different ways of moving and can come in sensitive and latent varieties. One way of controlling those is through control layers like vapor barriers, though these aren't always needed; we must understand the vapor flow to determine if a vapor barrier is necessary.

Dr. Bailes and Bryan also discuss:

Energy Vanguard's resources
The chapters of "A House Needs to Breathe... Or Does It?"
IAQ - filtration, humidity control, ventilation, and source control
Challenges with attic air
Dr. Bailes's book-writing process
The HVACR Training Symposium and other events w/ Dr. Bailes

Keep up with Energy Vanguard, read the blog, and subscribe to the weekly newsletter at https://www.energyvanguard.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

What the Heck is High Performance HVAC w/ David Holt Jan 19, 2023

David Holt with the National Comfort Institute (NCI) returns to the podcast to talk about high-performance HVAC and what the heck it even is.

High-performance HVAC is all about delivering the highest possible equipment performance out of the box. High-performance HVAC is a key element of NCI's work; equipment should be able to deliver the health, comfort, safety, reliability, and efficiency expected by the occupants, and equipment that can't do that often has root issues we need to troubleshoot and fix. In many cases, the root cause has something to do with airflow issues.

As contractors, we can focus more heavily on testing fan airflow to get to the bottom of poor HVAC performance, even when there may not be an apparent airflow problem. We need the proper test instrumentation to measure CFM, a key indicator of performance. We can't expect to maximize system performance until the airflow is correct across the heat exchange surfaces.

Many factors that contribute to poor equipment performance actually have to do with building science, including issues like air leakage. Although HVAC contractors can't control that, we can be successful if we have a culture and mindset that makes us put our customers first and work with the circumstances we're given to deliver the best possible solution.

David and Bryan also discuss:

David's role at NCI
Manufacturer, distributor, contractor, technician, and customer relationships
How to measure CFM effectively
Effects of improperly
Issues that arise during building construction
Parts vs. equipment vs. systems
What makes a good service technician
The high-performance mindset
Having a classroom vs. a commitment to training

If you want to get more involved in HVAC training, you can text David at (706)-332-2212 or visit https://nationalcomfortinstitute.com/pro/. Learn more about NCI's High-Performance HVAC Summit at https://www.gotosummit.com/.

Check out the HVACR Training Symposium and order your virtual tickets before, during, or after the symposium (Jan 19-21, 2023) at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Setting Realistic Customer Expectations w/ Ed Janowiak Jan 12, 2023

Ed Janowiak returns to the podcast to talk about setting realistic customer expectations when designing residential HVAC systems across climates, seasons, and load conditions.

Being honest and aggressive is one of the best ways to set realistic expectations, and our load calculations and equipment selection need to reflect that. Manual J calculations must consider non-design days, not just the design conditions, including partial load conditions. Partial load conditions that aren't accounted for may make it more difficult for the HVAC system to control latent heat, potentially leading to moisture problems indoors.

We have to set expectations in the summer a bit differently than we set expectations in the winter, and we must account for the equipment type when we create expectations. Heat pumps perform differently than furnaces, and oversized furnaces typically present fewer problems than oversized heat pumps in areas with high latent loads.

Clients must also be willing to acknowledge that systems won't perform exactly as designed during partial load conditions. You can put the information in writing and make clients sign the paperwork to ensure that they understand the expectations you've set. Laying out expectations and making clients read them is a good way to prevent conflict or identify clients that may not accept the expectations.

Ed and Bryan also discuss:

Ed's three "Hate Me" reasons
Oversizing furnaces vs. straight-cool A/C units vs. heat pumps
Electrification
Heat pumps in cold climates
Humid vs. arid climates
Designing systems with ancillary dehumidification
Not being responsible for clients' lifestyle choices
ACCA collaboration and industry support

Learn more about the training ACCA has to offer at https://www.acca.org.

Check out the HVACR Training Symposium and order your virtual tickets before, during, or after the symposium (Jan 19-21, 2023) at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Mini Split Install and Service Tips Jan 03, 2023

Craig Migliaccio, aka AC Service Tech, returns to the podcast to share his knowledge about mini-split install & service. He also talks a bit about his upcoming book, “Inverter Mini-Split Operation and Service Procedures.”

Mini-splits are unique because they are compartmentalized in ways that traditional central-air ducted systems are not. Mini-splits come in many varieties, including ducted and ductless types, as well as multi-zone types. Many are inverter-driven and have more electrical efficiency as a result and can vary their capacities based on load variation.

Mini-splits have metering devices at their outdoor units, and these devices may be electric expansion valves (EEVs) or capillary tubes. Inverter mini-splits also don’t have filter driers because their PVE oil doesn’t have the same acid concerns as POE oil, and they don’t have traditional liquid lines.

Flare connections are also critical when installing ductless systems, especially because you want systems to be tight to prevent leaking and contamination. Craig likes eccentric flaring tools with offset cones, and he recommends using flare nuts from the equipment manufacturer, not the line set manufacturer. He covers other flaring best practices as well.

The charge is quite small in mini-splits, so weighing the charge and being careful and deliberate during charging is critical. Refrigerant leaks can also be highly problematic; corrosion and poor flare connections are common causes of leaks.

Craig and Bryan also discuss:

Hyper-heat systems
Coefficient of performance (COP) and BTU output
Moving between PSC and ECM or inverter technologies
Mini-splits vs. VRF/VRV technologies
Pressure testing and leak detection
Compressor diagnosis
Thermistors and electrical resistance
Heat sinks and mounting circuit boards
Selecting a location to install a mini-split
Things to consider when checking the charge
Why measure superheat and subcooling?
Cleaning and maintenance best practices

Check out Craig’s YouTube channel at https://www.youtube.com/@acservicetech.

Starting January 1st, 2023, you can buy Craig’s book on his website, which has a bunch of other good resources. Visit that site at https://www.acservicetech.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

CO Doesn't Leak w/ David Richardson Dec 29, 2022

David Richardson from NCI returns to the podcast to talk about why CO (carbon monoxide) doesn't leak and what it does instead.

CO is a highly dangerous gas that is colorless and odorless, and we can keep ourselves safe by staying aware of it with personal low-level CO monitors. However, CO doesn't leak; it spills, especially via backdrafting, a blocked flue, or updrafting. Whenever the flue gas comes back inside the structure unintentionally, there is room for a potential CO problem. With proper testing, we can determine the cause of that spillage and make the best choice to stop it from happening.

When there is an excessive draft, there's often turbulence in the draft hoods, which leads to spillage. Spillage commonly happens at the draft hood, but it can also happen near the burner compartment of a gas appliance. Smoke tests won't detect that, but CO testing will. However, we need to look for rising CO levels over the run cycle of the equipment. If you test CO levels in the ducts, you're only seeing how the fans are distributing the CO; you're not checking the likely source of CO. Water heaters often give visual clues of improper venting, especially if there's soot, rust near the venting, or discoloration near the burner compartment.

David and Bryan also cover:

CO poisoning symptoms
CO monitors vs. alarms
The roles of stack effect and airflow in CO spillage
Air taking the path of least resistance
CO testing best practices
CO and changes in sinus pressure
Combustible gas leak detectors
Low-level CO monitors
Wind and its effects on pressurization or depressurization
Electric appliances, generators, and CO poisoning

Learn more about NCI's training courses at http://nationalcomfortinstitute.com/. You can also contact David directly at davidr@ncihvac.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

One HSI Furnace Control to Rule Them All w/ Jim Fultz Dec 27, 2022

Jim Fultz with Emerson White-Rodgers returns to the podcast to talk about one HSI furnace control to rule them all, the 50M56X-843 Universal Single Stage Integrated Furnace Control.

The 50M56X does not come with wiring harnesses; the control comes with the plugs that the majority of manufacturers use, making it a versatile and user-friendly universal part. It also works with the White-Rodgers Connect app to help you configure the part with the burners. You can also do some basic configuration when it comes to the blower motor. With the 50M56X and Emerson White-Rodgers Connect app combination, you can quickly and accurately configure the control without wi-fi or a password.

An igniter is included in the box with the 50M56X; the igniter must match the control. The control also comes with a three-digit display that communicates the microamp current from the flame sensor, meaning you don’t need to use a meter on the flame sensor. So, you can carry less truck stock and complete more calls with this universal part.

The device also has some potentially useful extra features. For example, the 50M56X stores error codes for 14 days, not permanently, to prevent causing confusion for future technicians. It also has a bus connector for the thermostat and a dehumidification terminal for thermostats with dehumidification capabilities.

Jim and Bryan also cover:

White-Rodgers universal vs. aftermarket vs. OEM parts
Blower speed and X13, ECM, and PSC motors
Near-field communication (NFC) capabilities
Cross-referencing
Technology and ethical business
50M56X warranty information
Integration with Sensi thermostats
WR Mobile App (available on Google Play and the App Store)

Learn about Emerson White-Rodgers and their featured products on our partner page HERE.

Check out the wide array of products and resources Emerson White-Rodgers has to offer at https://emerson.com/universalcontrols.

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Using Ice to Balance Energy Consumption Dec 22, 2022

Yaron Ben Nun from Nostromo Energy joins the podcast to talk about ice banking, a way of using ice to balance energy consumption. Nostromo Energy is an Israel-based company that has recently started working in California.

Water has a very high latent heat of fusion, meaning it can absorb and store a lot of energy between its solid and liquid states of matter. By storing ice, Nostromo Energy can support commercial and industrial structures that utilize chiller-type applications by offering a clean and sustainable battery thanks to water and its physical properties. Load balancing or management will be critical as the electrification of heating sources continues. Lithium-ion batteries aren't sustainable solutions in many of these cases, and that's where ice banking can support the grid by providing a thermal battery.

Water offers many advantages as a medium for storing energy, especially since it is natural and doesn't have the numerous economic and labor concerns that come with the production of many other batteries. However, there have been some challenges with the widespread adoption of ice banking, especially when it comes to retrofitting and the ability to match the demand for new power stations. Water is also heavy, meaning that it can be difficult to manage in rooftop applications.

Nostromo Energy keeps working to solve those problems and increase the coefficient of performance (COP), especially by maintaining a relatively high freezing temperature.

Yaron and Bryan also discuss:

Yaron's career and Nostromo Energy
HVAC equipment and the electrical grid
Economic and labor factors of lithium-ion battery production
Discharge rates and glycol cycles
COP and compression ratio
Heat recovery chiller technology
Carbon counting, kilowatt-hours, and carbon emission
Thermal energy storage and tax rebate eligibility

Learn more at nostromo.energy.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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We need to Pay Better! - An Audio Manifesto Dec 20, 2022

Eric Kaiser and Ty Branaman return to the podcast to talk about why we need to pay technicians and field workers better in the HVAC industry and how small and medium businesses can help current employees.

When the pay for entry-level HVAC positions can't compete with fast-food, retail, or warehousing jobs, we can't expect people to flock to the industry, especially since so much skill is required. Overtime is also almost unavoidable in many places, and it's a problem that requires a more nuanced solution than getting more trucks on the road. The tricky part about paying more for overtime is that it's challenging to implement pricing structures that charge the end user proportionally.

As prices for equipment, fuel, and living essentials go up, the company often has to eat those extra costs if they want to pay their technicians fairly. In some cases, HVAC businesses feel bad for the customer when the cost of everything increases, which could be doing a disservice to the techs who deserve higher wages for their work. HVAC companies can increase their value by setting themselves apart in their markets, such as by performing unique services that benefit customers; effort and skill are required, which can justify higher prices. We have to be realistic about what our competitors are selling and work towards selling comfort, not just parts or systems.

Eric, Ty, and Bryan also discuss:

Challenges with reducing overtime
HVAC sales and higher pay rates
Customers' willingness to pay
Base pay and incentives
How managers can take care of their employees
Understanding employee motivation
Using profits for personal luxury items vs. reinvesting in a business
Knowing our numbers
Understanding employee discussions about pay

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Refrigerant Myth Busting w/ Dr. Chuck Dec 15, 2022

Dr. Chuck Allgood from Chemours returns to the podcast to do some refrigerant myth-busting.

Many people don’t understand why high-GWP HFCs can impact the atmosphere if the refrigerant is heavier than air. High-GWP HFCs exist for a long time, and they last long enough for natural mixing and the wind to distribute their molecules throughout the atmosphere. HFOs, by comparison, are more reactive in the atmosphere and have relatively short lifespans, meaning they have less of an effect on the environment.

Even though refrigerants with lower GWPs are entering the market, it’s always been our job to keep refrigerants inside the system where they can’t harm the environment. However, when leaks occur, these lower-GWP refrigerants break down quickly outside the system but not inside it. Contractors and manufacturers should still work together to reduce leak rates as much as possible, even as we keep innovating.

Another common myth is around “natural refrigerants,” which are common in some forms of refrigeration, but “natural refrigerants” may be a misleading term; although you find them in nature, they undergo heavy manufacturing and processing before being used in HVAC/R systems. Even “non-toxic” and “non-flammable” labels for A1 refrigerants may be misleading, as they don’t capture the full picture of their risks.

There are also some myths around oil miscibility; oil still needs the help of refrigerant velocity and volume to move it through a system. POE and PVE oil are great in terms of miscibility and also get entrained in the refrigerant to ensure good oil return to the compressor.

Dr. Chuck and Bryan also discuss:

Dr. Chuck’s recent work and research
“Heat rises” and buoyancy
Pseudoscience
HFO stability and reactivity
Trifluoroacetate (TFA), toxicity, “forever chemicals”
Education and change in the industry
“Future-proof” vs. innovation
Phosgene

Learn more about Chemours and their A2L training at opteon.com. You can also check out the Chemours/Opteon YouTube channel at https://www.youtube.com/@OpteonProducts/videos.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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The Good, Bad and Ugly of Trade Schools Dec 13, 2022

Ty Branaman and Eric Kaiser return to the podcast to discuss the good, the bad, and the ugly of trade schools. They cover the opportunities and challenges they've observed in trade schools.

As with for-profit colleges, for-profit trade schools market programs aggressively and can take people who are at a crossroads in their life and saddle them with debt. In some cases, trade schools are hesitant to fail people and end up passing people who don't have the technical proficiency to be effective tradespeople. Sometimes, trade schools don't emphasize practical skills and contractors' experiences as much as they could, either.

The tricky part about trade schools is their allocation of resources, which instructors typically can't control. Sometimes, too much money is spent on equipment, and not enough is spent on the instructors. There needs to be an appropriate balance of both in an effective program. Administrative distractions can also make programs less likely to produce effective technicians. The admission process also doesn't always sort people into appropriate classes; many people with low proficiency are put into classes that are too advanced for them.

People are going into trade schools with less mechanical aptitude than in previous generations, and trade schools often skip over the basics of tool use. Students need to know how to use tools before they learn how to fix systems, and that tool proficiency needs to be reinforced. Continuing education is also more focused on paperwork than application and isn't as thorough as it probably could be.

Ty, Eric, and Bryan also discuss:

First-generation trade school graduates
Administrative challenges with trades instructors
Motivating students
Instructor qualifications
"PowerPoint teaching"
Automated systems
Bringing work experience to the classroom
Where does podcasting fit into trades education?

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Selecting Proper Cleaners w/ John Pastorello Dec 08, 2022

John Pastorello from Refrigeration Technologies returns to the podcast to talk about selecting proper cleaners for various HVAC/R jobs.

From the beginning, the goal of Refrigeration Technologies has been to make cleaners that are safe but have the same effectiveness as the strong, hazardous varieties in the industry. The more hazardous cleaners are not food safe and may be corrosive, dangerous to inhale, or irritating to the skin or eyes. Some cleaners can also damage components; brighteners aren’t recommended for use on aluminum coils for that reason.

John is a fan of foaming cleaners because the foam gives the cleaner more contact area and holds the detergent in place for a longer time. Foaming cleaners tend to be good for degreasing. However, if used improperly, the foam can overflow in the drain pan and get messy.

Many residential and light commercial HVAC contractors may benefit from keeping Viper EVAP+ for evaporator coils, Heavy Duty for condenser coils, and Brite only when there is an extremely dirty condenser coil. The Viper aerosol coil cleaner can also work well for small systems. The Pan & Drain Treatment also keeps drain sludge and odors at bay inside condensate lines and pans.

Instead of relying on harsh chemicals to dissolve microbial growth, Refrigeration Technologies cleaners help use enzymes to dissolve odor-causing biological material in HVAC systems.

John and Bryan also discuss:

PPE to use when working with cleaners
Acid-based cleaners and “non-acid” cleaners
Dwell time and contact
Dilution ratios
NSF registration and what it means to be “food-safe”
Viper Venom Packs

Watch our 3D video showing how to use several Refrigeration Technologies products HERE.

Learn more about Refrigeration Technologies products and resources at refrigtech.com.

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Good Tech, Good Service Manager? Dec 06, 2022

Eric Kaiser and Ty Branaman return to the podcast to talk about the progression from technician to service manager and if a good tech always makes a good service manager. They discuss career paths, differing skills between technicians and service managers, and how HVAC/R companies can support techs who wish to remain techs.

In many cases, top technicians are pulled into service manager positions to keep them with the company. Sometimes, older technicians who have lost some mobility and strength over the years end up going to managerial positions to stay in the industry. Some people genuinely want to acquire managerial positions. Not everybody is motivated by promotions, and HVAC business managers would benefit from knowing what their employees value and want for their professional lives.

Just as we have to teach technicians hard skills to be good at their jobs, we have to teach soft skills to service managers. We can't expect skilled technicians to enjoy or feel comfortable in leadership positions without knowledge of the expectations and required skills. When people genuinely want to go into service manager positions, they can benefit from having a clear path supported by goals and frequent performance reviews to keep them on the right track. However, some people may want to stay technicians; we can do right by them to keep their bodies in good shape so that they can get the most out of their careers and be able to enjoy all types of activities after they retire.

Ty, Eric, and Bryan also discuss:

Leadership training
Setting expectations for positions
Keeping technicians happy
Residential vs. Commercial HVAC soft skills
Taking care of employees over customers
Making room for different personalities and providing opportunities for them

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Why Aren't the Trades More Respected? w/ Kimberly Llewellyn Dec 01, 2022

Kimberly Llewellyn from METUS joins the podcast to talk about the value system around the trades and why the trades aren’t more respected.

In many cases, the people who are involved in engineering and design miss the practical details that the tradespeople would be able to pick up on. In many cases, tradespeople aren’t consulted early enough in the design process, and their input deserves to be brought to the table. Often, not everyone on a project team is on board with the project's goal, and the trades need to be on board from the beginning to work towards the same goal as the architects and engineers.

However, the trades aren’t as respected because of the current American dream’s emphasis on 4-year college, even despite the student loan debt problem many college graduates have. Despite that, building and troubleshooting systems that are necessary for survival is a fundamental skill for society.

The trades can be especially hard on people and leave them feeling beaten down. To reengage the tradespeople and affirm their value, we need to give them credit for their contributions and expertise. It would also benefit younger generations if we could map out a trades career path and make the career progression opportunities clearer.

Kimberly and Bryan also discuss:

Kimberly’s experiences with the trades
Theory vs. practice
4-year college, the trades, and our current value system in education
Professionalism and being treated as professionals
Revising contracts and liability concerns (for contractors/subcontractors)
Having mutual respect
Consultation and what it means in the trades
Working for manufacturers and other career opportunities
Contracting as a “race to the bottom”
Funding training programs vs. investing in people
Mentorship in the trades
Underpriced bids and pricing methods

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Getting More People Into The Trade Nov 29, 2022

Eric Kaiser and Ty Branaman return to the podcast to talk about getting more people into the trade. They focus on how the HVAC/R industry could be better at attracting and training skilled workers, not just getting more bodies to fill HVAC/R tech and installer positions.

People are starting to see more value in skilled trades careers, but it's difficult to find people who share your company's values and want to grow as HVAC/R professionals. Skilled tradespeople need time, education, and money invested in them, so it can be difficult for HVAC/R business owners to make those investments when other jobs pay close to the same without the same degree of investment from the company and the employee.

To attract more people to the trade, HVAC/R business owners ought to focus on how to give their employees a means of giving a good life. That means making incremental changes to employee pay, benefits, and training to make the trades a competitive option for people who want to improve their skills and grow. We could consider increasing entry-level pay to attract skilled people, allowing us to be more selective in our hiring. Performance reviews can also be more goal-focused to help HVAC/R talent grow within a company. Companies also ought to focus on training their tradespeople to use the many tools at their disposal nowadays; providing these tools and acknowledging the needs of employees will make the industry much more appealing and competitive.

Eric, Ty, and Bryan also discuss:

Labor organizations
Making gradual changes to the industry
Competing with other similar industries
Changing landscape of job ads and applications
"Back in my day..."
Ways of providing tools

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Becoming a Complete Tech Nov 24, 2022

Genry Garcia returns to the HVAC School podcast to talk about what becoming a complete tech really means and entails. He talks about his professional journey and what we must do to address our deficiencies.

Career progression looks a bit different for everyone, with some technicians going to trade school and others starting as helpers and working their way up. We get used to taking readings and start noticing patterns. Then, we start understanding why we see certain pressures. Our experiences are our most valuable tools for becoming better technicians, but they can be reinforced with other learning materials, including books and podcasts.

There comes a point when we acknowledge that we are solid technician but may want to specialize in a certain aspect of the trade. For Genry, that was building performance and humidity control; along the way, he listened to people who knew more than him and took on many jobs that he’d learn from and would keep him humble.

Everything goes back to the basics; we have to be able to solve all the basic problems and understand the fundamentals. Then and only then can we start thinking about building performance and focus on becoming experts at it. However, we also have to assess our ecosystem and see if it would allow us to grow or if it’s more suited for stability. We also have to be willing to be wrong and grow from those mistakes.

Genry and Bryan also discuss:

The pros and cons of trade school
Egos and admitting wrongdoing
Mental models
Humidity control
Looking back on previous work with shame
Building envelopes, pressures, and leakage
Where and how to learn more about building science and performance
Self-auditing and the Dunning-Kruger effect

Get in touch with Genry on Facebook by joining his Facebook Group HERE.

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Inductive Current Myths - Short #158 Nov 22, 2022

In this short podcast in our electrical myths series, Bryan talks about some inductive current myths.

There is a common myth surrounding voltage drop in inductive loads. When you decrease the voltage in a circuit with a resistive load, you'll see a relatively proportional drop in resistance (ohms) and current in accordance with Ohm's law. So, we'll see a decrease in current, but we have to keep in mind that load temperatures also affect the resistance (and the current, by extension).

Some people will claim that reducing the voltage in an inductive load (like a motor or compressor) will increase the current. That is actually generally a myth; many people believe this myth because the current drop is NOT proportional, unlike in resistive loads. The resistance that shows up in a motor is called inductive reactance, which is an opposing magnetic field that creates back electromotive force (back EMF) and impedes the circuit. Back EMF and inductive reactance contribute to the impedance or total resistance of the circuit. Decreasing the voltage may cause the resistance to increase, as some of the work will start contributing to heat instead of mechanical motion; the motor derates, becomes less efficient, and draws more current than it needs, but it doesn't actually draw more total current.

However, some variable-speed motors on VFDs may draw more current because the motor module speeds up the motor to make up for the voltage deficiency, static pressure, etc. ECMs also fall into this category and may draw more current if the motor module or VFD calls for it. However, in terms of simple electrical math without VFD logic, the current won't typically increase if the voltage drops, even in inductive loads.

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Why it REALLY gets hot upstairs w/ Alex Meaney Nov 17, 2022

Alex Meaney returns to the podcast to explain why it REALLY gets hot upstairs and what we can do about it. He also talks a bit about his new business.

Heat technically doesn’t rise; warm air is less dense than cooler air, so cooler air sinks as warmer air rises. In many cases, people blame stratification and the stack effect for warm upstairs areas, but there may actually be other issues at play, especially if the issue only seems to happen in the summer.

Many apparent convective problems are actually due to building science errors, especially poor insulation when walls are exposed to attic space. When air moves via convection, it brings the heat it contains with it, which can contribute to comfort problems. To help figure out what is going on, try to see what the floor temperature is; a cold floor usually indicates a building design mistake, particularly a joist bag problem.

Some of the solutions that may sound good aren’t actually that effective, including placing return ducts higher. In many cases, we have to think about fixing the actual building, not the HVAC system. Some attics that are poorly ventilated and insulated will need to be reinforced.

Alex and Bryan also discuss:

Mean HVAC Consulting & Design
Wind washing and exposure within the insulation
R-value
Pressurization and how it relates to hot air “rising”
Manual J and its shortcomings with significant heat gains/losses
Duct design and using a Ductulator
Soffit vents, ridge vents, blown-in insulation, and infiltration
Why building science skills are important for HVAC technicians
Poorly conceived home designs
Diagnostic tips and tricks
Vapor-permeable air barriers
Sizing, capacity, and power consumption

Learn more about what Alex is doing at meanhvac.com.

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Electrical Myths - Single phase is Really 2-Phase - Short #157 Nov 15, 2022

In this short podcast, Bryan busts the common electrical myth that single-phase 240v power is really two-phase power.

When power goes into a structure that runs 240v appliances, we may understand that two 120v sine waves are 180 degrees out of phase with each other, but that isn’t 100% accurate. If we were to use an oscilloscope to watch the electrical sine waves, we would see two sine waves 180 degrees out of phase because the transformers are center-tapped. Center-tapping creates a neutral center point that becomes our reference.

The transformer has two sides: a primary and a secondary. The number of wraps on each side is proportional to the other, and the number of wraps also dictates whether a transformer steps the voltage up or down. However, when you use the center tap as a reference, that also makes the voltage appear to be halved.

In many residential structures, a single phase of power goes into the transformer from the power company. If you were to use the center tap as your reference on each side of that transformer, you would read 120v; the two 120v readings add up to 240v. However, if you were to use the other side as the reference (as in a corner-tapped transformer), you would read 240v.

On an oscilloscope, you would see the same thing; using the center tap as the reference, you would see two 120v sine waves completely opposite each other. If you were to measure completely across the transformer, however, you would see a single 240v wave, which is larger.

Remember: only one phase comes from the power company. We only appear to get two separate waves because of our available point of reference.

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Pumping Away, Hydronics Changes And Electrification Nov 10, 2022

Moe Hirsch joins the podcast to discuss the hydronics side of the industry, particularly focusing on Dan Holohan’s Pumping Away and exciting developments in the hydronics market, especially regarding electrification.

Pumping Away is many people’s entry point to hydronics. It contains some good basic information about boilers, especially when it comes to learning about the pressures involved in pumping and how the components manipulate pressure throughout the system.

Boilers use many of the same fundamentals as compression-refrigeration HVAC systems; pressure drops are similar, as are phase changes in steam boilers. Boilers also employ pumps instead of compressors, but the processes are similar.

The pump or circulator makes a pressure differential within the boiler, which adds pressure to the circulator outlet and results in negative pressure on the suction side. However, problems like air bubbles and magnetite buildup can negatively impact performance.

The electrification side of the boiler industry is exciting, especially because of the relative safety of electricity compared to combustible fossil fuels. However, electrification comes with its own set of concerns, especially when natural gas prices are low. In some markets, electrical grids also haven’t caught up with the demand for electricity yet.

Moe and Bryan also discuss:

Moe’s recent work in the industry
Changes in boiler infrastructure over the years
Pumping away from the boiler vs. pumping at the boiler
Pressure’s role in boiler systems
Similarities between parallel racks and boilers
Challenges with ECM circulators
Evolution of boiler motors and controls
Magnetic and hydraulic circulation
Low-temperature heat pumps with radiant heated systems
Moe’s ideal HVAC system
Natural gas health and safety risks (carbon monoxide)

To learn more about what Moe is doing, check out turnupthecomfort.com or contact Moe directly at info@turnupthecomfort.com.

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Check out our handy calculators HERE.

Electrical Myths - Hard Starts Reduce Start Current - Short #156 Nov 08, 2022

In this short podcast, Bryan busts the myth that hard starts reduce the start current on the run winding of a compressor.

A single-phase motor’s main winding is the run winding; it has a lower resistance and a higher current than the auxiliary winding, also known as the start winding.

Hard start kits are often used on HVAC systems with single-phase compressors (which usually have PSC motors). These kits usually consist of a start capacitor and a potential relay, which takes the start capacitor out of the circuit. We don’t typically use hard starts on three-phase motors or ECMs.

Single-phase compressors often have to start under a big load, especially in long-line applications (at the manufacturer’s recommendation) or if the compressor simply has a hard time starting. In cases where you have a voltage drop or low voltage, particularly due to long branch circuits, you may also use a hard start kit. However, they do NOT reduce the starting current or “save” compressors.

Hard starts reduce the time-averaged starting current because they get the compressor to start up more quickly (therefore, the starting current is higher for a shorter time). However, hard starts do NOT reduce the spike of current upon startup. Like run capacitors, hard start kits allow current to flow on the start winding, but the run winding current stays the same.

Hard start kits boost the start winding current faster, not at a lower current, reducing how long the system is in locked rotor. If they stay in the circuit too long, they could overheat the start winding and need to be taken out. Therefore, we don’t want to use hard start kits without careful consideration.

Soft starts are different entirely; they CAN reduce starting current.

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The 24-Hour Technician w/ Andy Holt Nov 03, 2022

Andy Holt joins the podcast to talk about what it means to be a 24-Hour Technician. We talk about what it means to be HVAC/R technicians AND deal with the human aspects of our lives at the same time.

Service technicians differ from installers in that they do much of their work solitarily. They spend a lot of time by themselves. They’re also on their feet very often and may do emotionally exhausting work, but they can earn a respectable living and accumulate savings for the future. To make our work and the emotional burdens that come with it more manageable, we can try to control how we react—take out head trash.

Most people—but especially technicians—experience anxiety, and worrying about things takes a major toll on us. We also may need to apologize to people who we simply can’t access. Andy goes over some of his best tips for dealing with those sources of worry. The goal is to eliminate negativity—clearing up negative aspects of your life and not being weighed down by individuals who negatively affect your life.

As technicians, we do a lot of work to help other people, and the opportunities are endless for us. Customers may not always understand the value of the work we do, but we can bring positive experiences to them. We can find a lot of fulfillment in our work that way and bring positivity to our own lives.

Andy and Bryan also discuss:

Replacing negative thoughts with more positive ones
The power of handshakes and eye contact
Carrying burdens and being kind
Apologies and forgiveness
How to apologize to inaccessible people
Being a “24-Hour person”
Using overtime to avoid our lives outside of work
How to manage anxiety
Casting a future
Andy Holt’s Outdoor University

To get in touch with Andy, visit https://toprate.com/ or call (706)-888-2332. You can also email Andy at andy@toprate.com.

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Furnace Commissioning w/ MeasureQuick 2.0 Oct 27, 2022

Jim Bergmann returns to the podcast to talk about furnace commissioning procedures and the development of measureQuick 2.0.

MeasureQuick 2.0 has been a collaborative effort between Jim Bergmann and Joe Medosch, and it comes with an upgraded user interface that allows for faster operation and easier system data access and storage, and it works with more tool manufacturers’ tools.

Gas furnaces need to be commissioned to reach their maximum potential (and lifespan). MeasureQuick 2.0 provides commissioning instructions and recommends starting with a visual inspection, including the flame rectification system (rod, circuit board, and grounding). Electricity is conducted during the flame rectification process—only in the microamp scale—so a dedicated circuit is crucial to keep it working as it should.

When commissioning a high-efficiency furnace, we should make sure the condensate drain cannot become clogged. The filter should block the airstream completely and not allow for any bypass, which could make the secondary heat exchanger, condensate drain, or circuit board dirty. The combustion air zone (CAZ) is also important; we don’t want contaminants in there, as those could create acids that rot out your furnace components.

Jim has also recently worked with the folks at TEC to make MeasureQuick 2.0 compatible with the TrueFlow grid and DG8. This integration allows you to identify airflow issues much more quickly and easily than before. MeasureQuick 2.0 also stores a lot more historical data, especially as it relates to the built-in visual inspection checklist.

Jim and Bryan also discuss:

The history and methodology of measureQuick 2.0
What technicians tend to miss the most
Furnace circuit boards
Electrical signals and flame rectification
Filtration best practices
IAQ accessories and pressure drop
Combustion air zone (CAZ)
Evolution of airflow measurement with measureQuick
Venting termination considerations
Clocking the meter and setting the fuel pressure
CO and CO air-free PPM
Low-level CO protection
Checking manifold and inlet pressure
Is the industry ready for universal heat pumps?

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Light Commercial PM Process Oct 20, 2022

Mike Klokus and Jeff Crable walk us through Kalos Services' light commercial PM process.

First, we verify that everyone is clear on the agreement. Then, we start the PM with a thorough visual inspection, taking copious notes about things that look concerning.

Once we’ve done a visual inspection, we clean the condensers. We try to use only water when possible, though safe cleaners may be necessary in some cases.

When checking the electrical components, we make sure the wires are neat and have tight connections. We take our electrical readings and check the capacitor.

Then, we check the system’s refrigerant temperatures and pressures. We measure the superheat, subcooling, and pressures throughout the system and record those.

Once we move indoors, we check and replace the filter in accordance with the agreement. We do another visual inspection at the air handler, paying special attention to blower wheel cleanliness, panel insulation, and wire routing and connections.

When cleaning the evaporator, we want to try to stick with water or self-rinse cleaners. We want to make sure that we use very mild chemicals, and any foaming cleaners should be diluted appropriately and rinsed entirely.

Drain cleaning is one of the most critical parts of a PM. We check for double traps and to make sure that the drain lines are properly pitched, trapped, and vented; vents should be uncapped, but cleanouts must be capped.

We finish with a final inspection, making sure all disconnects are back in, cleaning up all trash and tools, and sharing any notes with the customer.

Mike and Jeff also cover:

Cleaning microchannel and multi-row coils
Critical electrical readings
How to replace panels carefully
Filter replacement
Modifying ductwork and return boxes for accessibility
Cleaning drain pans thoroughly
Pulling and cleaning blower wheels
Common drains and condensate pumps
Traps, cleanouts, and vents
Testing heat strips
Finishing up calls

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Electrical Myth - Wire Length Code - Short #155 Oct 18, 2022

In this short podcast, Bryan covers a common electrical myth about wire length and its relationship with the National Electrical Code. The NEC is concerned with safety—protecting buildings and people—but less so with making sure things work.

Wire sizing is a common topic, and length is important because it can contribute to the voltage drop in a circuit. In many cases, we refer to the MCA (minimum circuit ampacity) to select an appropriate wire size.

If you run more current through an undersized conductor, it gets hotter and will experience a voltage drop—though not proportionally. It’s worth noting that nothing in the circuit is fixed; voltage, amperage, and resistance all follow Ohm’s law but are variable as different things start happening in a circuit.

In many cases, the NEC generally doesn’t require us to size conductors to accommodate for voltage drop. Conductors have some degree of resistance, so longer wires will result in a greater voltage drop than you would see in a shorter wire. It makes sense for the wire to overheat, but that won’t happen because the greater resistance in the circuit will reduce the current. There is less work being done.

Longer wires and circuits that are sized correctly shouldn’t overheat or present a safety issue. The NEC recommends but does not require voltage drop to stay below 5% across a conductor. That is a performance recommendation, not a safety concern. We need equipment to perform correctly, but NEC won’t prevent electricians from setting up branch circuits that are longer than the ideal length. Excessively long branch circuits are common in commercial structures, and it’s up to HVAC technicians to notice that and measure the voltage drop to make sure it’s not negatively affecting the equipment.

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Why CO2 Matters w/ Trevor Matthews Oct 13, 2022

Trevor Matthews, the founder of Refrigeration Mentor, returns to the podcast to talk about why CO2 matters in commercial refrigeration and even HVAC applications.

CO2 (R-744) has entered the residential HVAC sphere in some places around the world, though it hasn’t come to the North American markets yet. CO2 is one of the most eco-friendly refrigerants on the market, with a GWP of 1, and it’s very good at moving heat. However, CO2 has some challenges, including its low critical point and higher pressures.

CO2 comes with some safety concerns, and its systems have a complicated infrastructure. Since CO2 can exist as a liquid, vapor, or solid under operating conditions, you could end up with dry ice in the system. These issues require skilled, attentive technicians.

As the industry moves to natural refrigerants like CO2 and hydrocarbons, we need to stop the race to the bottom. Technicians need to learn how to take their time and do the job right when they work on CO2 equipment so that they can be safe and save energy.

The future of troubleshooting will eventually lie in electronic controls that take measurements constantly. Technicians won’t lose their necessity with these changes, but it will be easier for them to respond to those measurements directly without connecting gauges. Technicians will also be able to access performance logs, which can help diagnose long-term problems.

Trevor and Bryan also discuss:

Trevor’s history working with CO2
Refrigerant regulations
Transcritical CO2 and climate
The skills and proficiency of young technicians
Dry ice in CO2 systems
Pressure transducers and pressure release valves
Manufacturer support and quality control
Data logging and electronic controls in commercial refrigeration
Trevor’s recommended resources for CO2 education and training

Check out Trevor’s mentorship and training initiative at refrigerationmentor.com.

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Check out our handy calculators HERE.

Electrical Basics Oct 06, 2022

This podcast is Bryan’s full-length electrical basics class for the Kalos technicians. He covers electrical theory and circuit basics.

Volts, resistance, and amps all affect the behavior of electricity in circuits. These are also critical factors in electrical safety. Watts and kilowatts come from the multiplication of the volts and amps, though not every volt-amp does work; the power factor indicates how much work the volt-amps are actually doing. Some of the volt-amps are reactive (kVAR) and don’t do the real power of watts.

Electrons move by interacting with other atoms. Substances can be conductors or insulators, and conductors have very few valence electrons, which move in and out of other atoms easily. Insulators have many valence electrons and are more stable. Insulators have high resistance, and conductors tend to have low resistance.

Circuits consist of loads, switches, and power supplies. Loads actually do things and consist of light bulbs and motors. Switches pass power and don’t do work. Power supplies can be finite, like batteries, but also include transformers that take power from the utility company. Open circuits don’t move electricity, but closed circuits create a complete path that allows electrons to move. Electricity takes all available paths, not just the path of least resistance.

Bryan also covers:

Electricity and the body
GFCIs and AFCIs
Shock and arc flash protection
Lockout/tagout
Electricity and fall hazards
Energy transfer
Resistive vs. inductive loads
Magnetism and flux
Direct current (DC) vs. alternating current (AC)
How power companies and generators work
Open vs. short circuits
“Path of least resistance”
Tripping breakers
Electrical units of measurement
Step-up and step-down transformers
Electrical frequency (hertz)
Variable frequency drives (VFDs)
Microfarads and capacitors
Parallel and series circuits
Becoming more proficient at reading diagrams

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Myth: Path of Least Resistance - Short #154 Oct 04, 2022

In this short podcast, Bryan debunks the myth that electricity only takes the path of least resistance.

It is true that more current will typically take paths of lower resistance; it’s much easier for more electrons to flow through a path with lower resistance, which is consistent with Ohm’s law. Ohm’s law states that a circuit will have higher current with you have lower resistance so long as the voltage stays the same.

In most cases, the voltage stays relatively constant; transformers don’t often need to limit their currents, so there usually isn’t a voltage drop. When power supplies are regulated, the voltage is usually fixed, not the amperage. As a result, dropping the resistance in a circuit will increase the current.

Ohm’s law holds true for both resistive and inductive loads. Inductive loads, however, are a bit tricky because the resistance isn’t constant. As motors spin faster, they create back EMF or impedance, which is magnetic resistance. The resistance only shows up once a motor, solenoid, or another electromagnetic component is energized; the resistance is much more dynamic.

An electrical current takes ALL parallel paths, not just the path of least resistance. The current also stays proportional to the resistance, even when it takes paths of many different resistance values. Our bodies are also parallel paths, so there’s a risk of electric shock even though our bodies usually have much higher resistance than loads. Wet skin has less resistance than dry skin, so that’s why electricity and water are so dangerous to us; lower resistance means that more current can flow through our bodies.

If electricity ONLY took the path of least resistance, we wouldn’t be able to operate all the appliances and electrical components in our homes. The only prerequisite is an electrical potential (voltage).

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Dehumidification in Shoulder Seasons w/ Nikki Sep 29, 2022

Nikki Krueger from Santa Fe Dehumidifiers returns to the podcast to talk about dehumidification equipment and strategies in the shoulder seasons (spring and fall). The shoulder seasons (and the weeks leading up to them) are when many homeowners begin to notice moisture problems in their homes.

HVAC units and dehumidifiers should have a king-queen relationship. The HVAC unit is the king and controls the bulk of temperature and humidity during the day, but the dehumidifier can take care of the humidity when the king needs help. To remove moisture optimally, an HVAC unit needs longer runtimes and a cold evaporator coil. However, there will still likely be gaps in performance, and that’s when the dehumidifier can step in.

Proper equipment sizing can help us achieve better runtimes; we want to avoid oversizing the HVAC equipment, but oversizing is a bit less critical when it comes to installing dehumidifiers. The actual install configuration is more important when it comes to dehumidifiers (i.e., whether it takes supply or return air and ties into the supply or return).

Dehumidification can be coupled with ventilation and filtration; ventilating dehumidifiers bring in outdoor air and should filter it before dehumidifying. The air mixing tends to occur in the dehumidifier, and the mixed, dehumidified air then moves into the supply airstream.

Nikki and Bryan also discuss:

Condensating vents, walls, and equipment
Modern homes, energy efficiency, and HVAC
Infiltration and the building envelope’s effect on humidity
Effects of equipment sizing and wall/duct insulation
Fan speed, air mixing, condensation, and humidity
Andy Ask and Ken Gehring’s contributions and legacies
Humidity from household habits and behaviors
Santa Fe Oasis 105 features and operation

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Check out our handy calculators HERE.

Time Management - Short #153 Sep 27, 2022

In this short podcast episode, Bryan gives some quick tips for time management. You can save a lot of time by prioritizing what really matters and delegating tasks.

One of the simplest but most effective ways to manage your time is to use a calendar. You can even apply the calendar to your personal life; you can get into a habit of scheduling important appointments, deadlines, and tasks. Google Calendar also allows other people to see and interact with your schedule, so it’s a great tool for scheduling performance reviews, interviews, and meetings.

When you prioritize things, think about the negative and positive impacts of each thing. The ones with the highest positive and negative impacts should take priority over things with less significant positive or negative impacts. Many of the major business initiatives take place in the slow season, and many of our urgent client issues take priority during the busy seasons.

Delegating is also a critical task. Just because you can do something, that doesn’t mean you should do it. So, it often makes more sense to give someone a task if they’re uniquely qualified for it. If someone is uniquely qualified to do a task, then you can delegate that task to them. Delegating is NOT the same as passing work to someone else because you don’t want to do it. To delegate effectively, you need to assess qualifications and prioritize.

On the management side, you can put processes in place that allow you to spend less time managing and more time doing meaningful things at work that you actually enjoy. Making videos and audio tutorials can make it easy to demonstrate processes and procedures within your company. Then, you can focus on leading by example, creating, and making everybody better overall.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Become a Better Mentor w/ Eric Kaiser Sep 22, 2022

Eric Kaiser returns to the podcast to talk about how to become a better mentor. He explains the topic from the perspective of a mentor and a mentee.

The goal of mentorship is to pass your knowledge on to someone else. When you give someone the knowledge to succeed in the HVAC/R trade, you move the trade forward and allow yourself to try new career opportunities when someone can replace you.

Some of the most effective mentorship strategies establish the mentor as a guide rather than someone who spoon-feeds the mentee. Mentorship is about supporting discovery, which also builds the relationship between the mentor and mentee. Mentors can also learn from their mentees when they allow their mentees to discover the answers to their questions.

Mentors can also benefit their mentees by talking about health, especially mental health. Those who have been in the trade a long time may know how to draw boundaries between their work and their personal lives; mentees can benefit from open discussions about those things, and it helps to know that their mentor cares for them. Good mentors help mentees prioritize their health and wellness and break mental health stigmas.

Mentors can also share references to other possible teachers with their mentees. Those relationships are especially important for mentors who don’t have all the answers. Mentorship provides the context for training, and those connections provide as much context as possible. Mentors can also be mentees themselves, and those relationships are what really advance the trade.

Eric and Bryan also discuss:

Online education vs. in-person mentorship
The role of the apprentice or mentee
The Socratic method
Mentoring people about health and safety practices
Bryan and Eric’s mentors
Recognizing who mentors are and treating them appropriately

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HVAC Measurement Types and Benefits Sep 15, 2022

Eric Kaiser joins the HVAC School podcast to talk about HVAC measurement types and the benefits of taking each one. He also talks about point measurements and data trends.

Point measurements include static pressure, voltage readings, and readings provided by gauges. We only take those measurements once. However, when you track those on several occasions over time, you can build data trends. Single-point measurements give us information about what is happening at the moment, but they don’t give us a long-term view of the system's health.

Absolute and differential measurements also have different purposes entirely. Absolute measurements require us to compare a reading to a specific, unchanging reference point, but differentials compare one measurement to another.

When we turn point measurements into trend measurements, we can see some degree of causation. Changes in data trends indicate that a problem occurred at a certain point in time and could be due to changes that coincided with the deviation from the norm. However, that’s intermittent trending that relies on us to take point measurements at spaced-out points in time. Continuous trending allows us to use sensors and test instruments that map changes constantly.

At the end of the day, point measurements are like snapshots, and continuous data trends are like videos; the former only shows part of the picture, and the latter can help us solve more difficult problems by giving us a more complete idea of what’s happening.

Eric and Bryan also discuss:

Qualitative vs. quantitative measurements
Filter restrictions and static pressure
Gauge vs. atmospheric pressure
Combined trend measurements
How tool usage and calibration impact measurements
Non-invasive testing
Recorded data and sample frequency
Comparative troubleshooting in spaces with similar equipment
Resolution vs. accuracy vs. precision

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Ventilation and 62.2 Intro & Rant w/ Genry Garcia Sep 08, 2022

Genry Garcia joins the podcast to give an intro to ASHRAE Standard 62.2. He and Bryan also share a nice rant about accountability in HVAC design. Standard 62.2 is the ventilation standard for low-rise residential buildings, which dilutes airborne contaminants like VOCs and CO2.

Before coming up with a ventilation strategy, we need to assess the leakage rate of the building, such as via a blower door test. However, we also need to consider how bringing in outdoor air might negatively affect efficiency and comfort if we don’t do it right.

Exhaust ventilation removes air from the structure and relies on infiltration to bring air back in. Instead, we can use controlled intake air, which is brought in from the outdoors instead of unconditioned spaces in the home.

Ventilating dehumidification is a strategy we can use to comply with 62.2; we can bring in filtered outdoor air and dehumidify it before injecting it into the supply ductwork. When we introduce ventilation in a Florida installation, bringing it in through the return is typically not ideal, especially if it’s unfiltered.

People can go wrong with 62.2 if they remain shortsighted; when designing ventilation systems, we need to think about a lot more than the load calculations and CFM of fresh air needed. We need to focus on accessibility, ventilation strategies, and location-specific installation practices. Consulting tradespeople during the design process would likely make ventilation systems much more accessible, sensible, and effective.

Genry and Bryan also discuss:

Ventilation as an IAQ strategy
Infiltration credits
Pressurization
Continuous vs. spot measurement
Holding the right people accountable during the design phase
Intermittent vs. continuous ventilation
Automating ventilation with sensors
Controlling ventilation on a timer
Genry’s ideal methods of controlling ventilation

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Pressure Enthalpy without Tears Sep 01, 2022

RACT manual co-author Eugene Silberstein joins the podcast to talk about the titular topic of his book, Pressure Enthalpy Without Tears.

Pressure Enthalpy Without Tears is a book that introduces engineering concepts to HVAC technicians in a way they can understand and apply in the field. Enthalpy is a fancy way of saying “heat,” and we use it to refer to the total heat content (BTUs).

The pressure-enthalpy chart shows the relationship between the refrigerant pressure and enthalpy in a system; it’s like a P-T chart that shows the relationship between heat content instead of temperature.

Each refrigerant has its own pressure-enthalpy chart, but the points and lines on the chart usually form a right trapezoid. Dirty air filters and other less-than-ideal conditions can distort the trapezoid or shift it on the chart. Each side of the trapezoid represents the refrigerant inside a major component of the HVAC system: evaporator, compressor, condenser, and metering device. The pressure-enthalpy diagram allows you to get a look at individual components while keeping the entire system in mind.

To plot points on a pressure-enthalpy chart, you need the high side pressure, low side pressure, condenser outlet temperature, evaporator outlet temperature, and compressor inlet temperature. Pressure is usually measured in absolute units (rather than gauge units), but ballpark estimates are typically sufficient.

Entropy is another concept we need to consider. Compression theoretically leaves no additional entropy and is reversible. Crossing a line of entropy means that a process is no longer reversible.

Eugene and Bryan also discuss:

Technicians vs. engineers
Temperature vs. heat content
Psychrometric and pressure-enthalpy charts
Using the pressure-enthalpy diagram to assess operation costs
Electrical measurements
Predicting compressor failure
Putting passion into learning and trades education

You can visit https://www.escogroup.org/ to purchase Pressure Enthalpy Without Tears and access all of ESCO Group’s resources. You can also use the code HVACSchool22 for a discount on ESCO Group’s eLearning services.

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Total Heat of Rejection - Short #152 Aug 30, 2022

In this short podcast, Bryan talks about THOR, total heat of rejection. He explains what it is and why we should care about it when working on HVAC/R systems. THOR is another aspect of pressure-enthalpy calculations, along with net refrigeration effect (NRE) and total heat of compression.

When we talk about system capacity, we’re often referring to heat absorbed in the evaporator coil (NRE). Heating is on the opposite side of the coin; when we bring heat into a home, we care more about how much heat is rejected than absorbed. That’s where THOR comes in.

More heat is rejected at the condenser than absorbed in the evaporator. The total heat content increases due to additional heat being absorbed in the suction line. Compressors also have motors that aren’t 100% efficient, so a bit of inefficiency also adds a small amount of heat to the refrigerant (in a system operating normally). All of that heat adds up to the total heat of rejection (THOR).

Even though a higher total heat of rejection is desirable when we want heat pumps to bring heat into the home, we don’t want our compression ratios and discharge temperatures to get too high. We have to avoid oil breakdown and other negative effects. So, modern heat pumps use variable frequency drive technologies or liquid or vapor injection to get a lot of capacity out of the compressor without overheating it.

The effective THOR only happens in the condenser. Some heat rejection may occur in the discharge line, but none of that is of use to us when we need to bring heat indoors.

Check out Eugene Silberstein’s book, Pressure Enthalpy Without Tears, at https://escogroup.org/shop/itemdetail.aspx?ID=1445.

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Hard Start vs. Easy Start Aug 25, 2022

Matteo Giovanetti from Micro-Air joins the HVAC School podcast to talk about the differences between a hard start and an EasyStart.

Micro-Air’s “EasyStart” provides a soft start rather than a hard start. A hard start abruptly ramps up the voltage and current to the motor start; a soft start is a much gentler start that results from a gradual voltage and current increase on the start AND run windings.

The EasyStart marks a paradigm shift in how we think about “saving” compressors. It attempts to avoid drawing unnecessary inrush current, which is very common with hard starts. Hard starts may even lead to premature failure if the potential relay fails and can’t take the start capacitor out of the circuit.

EasyStart has a different wiring configuration compared to hard start kits. A hard start kit consists of a start capacitor wired in series with a potential relay, which increases the torque on the compressor and removes the start capacitor from the circuit. The EasyStart has four wires; the black and white wires (L1 and L2) connect directly to the contactor, a brown wire that splices directly to the run winding, and an orange wire to the HERM terminal of the run capacitor.

EasyStart also records information about the compressor during the first few startups to optimize its performance. It also monitors overcurrent and fault conditions with phase detection; when it detects a stall, it shuts off the compressor and doesn’t attempt to restart it until a few minutes have passed.

Matteo and Bryan also discuss:

EasyStart models
Solar, generator, and RV use
Impedance
Positive temperature coefficient resistors (PTCRs)
Compressors running backward
EasyStart’s Bluetooth capabilities
Tech support and product education
Offering useful upgrades to customers
Running and starting watt specifications for generators

Learn more about EasyStart or purchase it directly from https://www.microair.net/. You can also contact the manufacturer by email at sales@microair.net.

You can view the EasyStart home installation video at https://www.youtube.com/watch?v=bp4U-husy1o&ab_channel=MicroAir.

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Heat of Compression - Short #151 Aug 23, 2022

In this short podcast, Bryan explains what the heat of compression is and why we should care about it as HVAC/R professionals.

More heat is rejected in the condenser than absorbed in the evaporator coil, and that’s because the compressor adds heat. That added heat is called “heat of compression.” That heat does NOT contribute to the net refrigeration effect (NRE), as it doesn’t contribute to cooling.

When we compress something, we increase the system entropy during that process. Entropy is the waste and disorder associated with work. There is some inefficiency, which we see in the form of additional heat. So, the HVAC system needs to reject that additional heat of compression, and we can plot and track reversible changes by following lines of constant entropy.

As the temperature increases, the molecules begin moving more quickly. However, the refrigerant doesn’t absorb many more BTUs in the compressor (in a properly operating system). The temperature spikes, but the compressor doesn’t typically add a significant number of BTUs to the refrigerant.

Heat also enters the system via the suction line, which also doesn’t contribute to the NRE. Long, uninsulated suction lines can absorb a lot of heat without cooling the space at all. That heat also has to be rejected in the condenser. So, short, well-insulated suction lines tend to absorb less heat.

When plotting the heat of compression, we’re looking at BTUs added into the system in the compressor, discharge line, and suction line. BTUs that don’t contribute to the NRE may fall under the “heat of compression” label, though the actual definition may vary by organization.

Check out Eugene Silberstein’s book, Pressure Enthalpy Without Tears, at https://escogroup.org/shop/itemdetail.aspx?ID=1445.

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Intro to ACCA Manual T Aug 18, 2022

Ed Janowiak joins the podcast to introduce us to ACCA Manual T.

Compared to other manuals, Manual T is one of the least-considered ACCA manuals. However, it’s the manual that advises us on how not to blow high-velocity air on people and has maintained the same standards since the mid-1900s. Unlike Manuals J, S, and D, Manual T is not recognized in code compliance.

Manual T deals with air distribution; it helps us find out the throw and spread, which informs our ductwork design in Manual D. We need to know the customer’s expectations and the air velocity we’ll need to manage at the registers before designing the ductwork. Register placement is also a critical element of Manual T.

Throw and spreqd can vary wildly, and register selection and placement are going to have a significant effect on comfort as a result. Register placement on the ceiling may achieve the Coanda effect to assist with air distribution, and that can be especially useful in low-load or passive homes. Low-load homes are an interesting case, as they use less hardware than other homes, meaning that we need to make the most of calculations and equipment selection.

Manual T ultimately focuses on using the diffusers and registers, rather than the equipment, to spread air throughout a space. Knowledge of the principles in Manual T also allows us to communicate, establish, and manage expectations with the customer.

Ed and Bryan also discuss:

Registers, diffusers, grilles, and vents
Filter restrictions
ACCA Manual LLH
Air movement in the occupied vs. unoccupied zone
Manual T as an extension of Manual D
What it means to lend credibility in this industry
Floor vs. ceiling registers based on climate

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Net Refrigeration Effect - Short #150 Aug 16, 2022

In this short podcast, Bryan explains what the net refrigeration effect (NRE) is and how it affects HVAC systems.

The net refrigeration effect (NRE) is what happens in the evaporator coil. The evaporator is the heat absorber; as air passes over the coil, the cooler refrigerant within the evaporator absorbs that heat and boils. The NRE is the net energy change that occurs during that process. You can plot the NRE on a pressure-enthalpy chart.

When air moves over the evaporator coil, there is a change in enthalpy or BTUs per pound in the refrigerant (usually called delta h). There should be more BTUs per pound in refrigerant exiting the coil than when it went in. We have to know how many pounds of refrigerant we’re circulating (mass flow rate) and how many BTUs are in those pounds.

Many of those BTUs come from latent heat transfer, which happens when the refrigerant boils. When refrigerant undergoes a phase change, it remains at a constant temperature (sensible heat), but it continues absorbing heat. The heat absorbed contributes to the phase change, and that’s latent heat. Most of the NRE deals with those latent BTUs. (Note: this does NOT refer to latent heat loads.)

In addition to the boiling or saturation phase, we also have to consider BTU changes when refrigerant flashes off at the beginning of the evaporator coil and heat obtained during the superheating phase at the top of the coil. We can maximize our NRE by running a cold evaporator coil (without freezing) and ensuring the evaporator is full of boiling refrigerant. BTUs absorbed in the suction line do NOT count towards the NRE, as they don’t contribute to cooling spaces or refrigerated boxes.

Check out Eugene Silberstein’s book, Pressure Enthalpy Without Tears, at https://escogroup.org/shop/itemdetail.aspx?ID=1445.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Systems Thinking - Gas and Combustion Aug 11, 2022

Eric Kaiser returns to the podcast to talk about how we can use systems thinking to approach gas appliances and combustion in HVAC installation and service.

Gas lines can be made of a few different materials, including black iron, copper, and CSST. These all have benefits, setbacks, and appropriate applications. For example, copper is common in propane (LP) systems but not natural gas. In coastal environments, galvanized pipe tends to be most common due to the increased likelihood of corrosion. Gas lines may also need sleeves to prevent them from interacting with moisture.

The piping also needs to be routed in accordance with code; in many cases, joints need to be exposed so that a technician can check for leaks. Keeping joints inside walls is risky, especially when light switches cause sparks and could potentially ignite leaking natural gas. In any case, leak detection can be tricky unless you have a combustible gas leak detector and bubbles that work well for gas lines.

Safety has to be the top priority when it comes to venting, especially on water heaters. A personal low-level CO monitor can also keep you and your customers safe by detecting small yet harmful amounts of carbon monoxide. Makeup air and combustion air are also important in gas appliances; unbalanced pressures may result in undesigned return paths. Traps and improper pitch may also lead to improper venting, as condensate may get trapped in the pipe and may lead to freezing or other complications.

Eric and Bryan also discuss:

Pipe material and flow rate
Pipe sizing and connectors
Regulator issues on gas water heaters and pool heaters
Thread sealant products and best practices
Bubble solution recommendations
Signs and risks of backdrafting
Exhaust pipe insulation
Drain installation

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HVAC School Admin Discussion - Moderating a Successful Community Aug 04, 2022

Some admins from the HVAC School Facebook group join the podcast to discuss the art of moderating a successful community. Bryan is joined by Eric Kaiser, Ty Branaman, Michael Housh, and Neil Comparetto.

A community based on a skilled trade gives people an inviting space to share information and ask questions. It’s also a space that allows people to practice how they present information. Groups also connect people across geographical locations, and we can get regional perspectives that change the way we think about things.

However, community standards are necessary to keep groups professional and on-topic. Swearing is a slippery slope that may lead to personal attacks, which make the community hostile and unhelpful. The main goal is to keep a respectful atmosphere, and moderators have to draw the line somewhere, but there’s a difference between cultivating a productive atmosphere and being dogmatic.

People who interact in those communities need to do it for altruistic reasons, not to satisfy their egos. Giving detailed, accurate answers (ideally with a source to back up the information) is the best way to contribute meaningfully. Engaging in rigorous debates with an open mind is also a great way to see many different viewpoints.

Debates in HVAC communities are great, but they require boundaries and mutual respect between debaters. Namecalling, blaming others, or dragging politics into the discussion is unproductive. Overall, it’s best to stay positive and try to keep things helpful, and admins try to maintain an atmosphere that can be both serious and lighthearted but is always helpful and respectful.

HVAC communities and groups are not places to share other groups, content, or job postings. These groups are not marketing centers; they are forums for learning and discussing the work we do every day.

Ty, Neil, Michael, Eric, and Bryan also talk about:

How they got started in online HVAC communities
Unproductive arguments about codes
Banning and muting members
Receiving feedback
Avoiding logical fallacies in debates
How egos hold people back
Trite and unproductive catchphrases, slogans, and jokes
Responding to disagreements productively
Communicating with people appropriately
Admitting fault and refraining from judging others who are incorrect
Moderating posts for quality and shareability

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Systems Thinking - HV / LV / Condensate Jul 28, 2022

Eric Kaiser returns to the podcast to discuss high-voltage wiring, low-voltage wiring, and condensate assemblies as they relate to systems thinking.

On the high-voltage side, the disconnect should be in a secure location, and it should be able to keep water out. The wires should be appropriately sized, have an appropriate level of tension, and should not be vulnerable to chafing or abrasion. Overall, best practices include using proper grommets and ensuring that you have a solid connection. Do not run high voltage wiring in parallel with low-voltage or control wiring. It’s also worth noting that double-lugging is a poor practice that is against code.

On the low-voltage side, you also need to be careful of where you route your wires to avoid induction, contact with hot surfaces, or abrasion. The insulation ratings also need to be appropriate.

We can think of the condensate assembly as its own system. Condensate drains have uphills and downhills, and they may have traps, vents, and cleanouts throughout. Cleanouts and vents may be confused for each other, but cleanouts allow the technician to access and clean the drain. Cleanouts are also capped when in use, but vents are not. The location of a vent can help equalize the siphoning effects of pressurization.

Condensate systems also consist of pans and switches. In those cases, redundancy is desirable to prevent overflowing. Secondary drain pans should be large enough to overlap with the primary pan, especially in horizontal air handlers.

Eric and Bryan also discuss:

Conductor length best practices
Connecting stranded to solid wire
Lug torquing
Variation in wire sizing
Testing low-voltage wires
Cleanout tees
Single vs. multiple drains with other appliances
Drain pitch and if there could be “too much fall”

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Systems Thinking - Copper & Line sets Jul 21, 2022

Eric Kaiser returns to the podcast to talk about how copper, piping, and line sets play into systems thinking.

Nowadays, we have to think about POE and PVE oil, and we need to design line sets in a way that assists with oil carry while preventing liquid refrigerant migration. The height of the evaporator relative to the condenser is a major factor to consider during the design phase.

Especially when chases are run underground, we need to watch for possible threats to the copper. Water softener discharge and excess pool water may damage the copper over time, and systems should be designed to keep line sets away from those. In many cases, Florida chases are sealed with mastic, which doesn’t prevent water from getting in (but does prevent rodents and insects from entering the home.

Flowing nitrogen is one of the best practices you can do while brazing. Nitrogen displaces oxygen, which contributes to oxidation and produces scale. When cutting copper, you will also want to make sure that you don’t get copper shavings inside the tube. The pressure test is also an important step for leak detection. Following the manufacturer’s instructions, pressurize the system and apply a liquid leak reactant (bubbles) to joints and other common leak points.

It’s a good idea to have at least one line drier in the system, and it should be able to work both ways in a heat pump system. Ideally, the line drier should be in a serviceable location, as it will be easier to detect restrictions when it’s on the line set.

Eric and Bryan also discuss:

Air and vapor barriers
Long line guidelines
Underground chase depth
Derate values
Controversial reaming/deburring practices
Line drier best practices

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Systems Thinking In HVAC w/ Eric K Jul 14, 2022

Eric Kaiser joins the podcast to talk about systems thinking in HVAC. Systems thinking allows us to solve problems and address customers’ comfort holistically instead of focusing on just the equipment. The key to systems thinking is to think outside the appliance.

System design plays a major role in performance. Duct design, drain placement, and equipment placement all matter, and we can only do so much to mitigate factors of poor design. We need to assess the building envelope and consider how the HVAC system interacts with it. Building envelope and duct leakage will significantly affect HVAC performance and occupant comfort.

Ventilation also matters, especially since many homes rely on exhaust-only ventilation. However, the air that leaves the building must be replaced, and we often don’t control where that air comes from. When you control the source of your fresh air ventilation to meet ASHRAE 62.2, filtration may further help control the quality of the air that comes in.

Installation and commissioning are other things we need to consider when thinking of the HVAC equipment systemically. The wiring needs to be correct, and we need to verify that the system is achieving the proper airflow in the first place. Static pressure is another factor that we must consider during commissioning, as an abnormal static pressure could indicate a filter that doesn’t fit or is too restrictive.

It’s best to start by looking at the appliance and widening your scope from there until you know about the system as a whole.

Eric and Bryan also discuss:

Is the house a duct system?
Oversizing equipment
Stack effect
Loose vs. tight houses
Filtration best practices
Radiant heat transfer
Ductwork best practices
Data trends of cause and effect

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Logical Fallacies - False Cause & Strawman Jul 07, 2022

Nathan Orr joins Bryan to talk about some logical fallacies, namely the false cause and strawman. They explain how those fallacies show up in the trade.

It’s difficult to present arguments without using fallacies, but people tend to rely on fallacies to uphold extreme religious or ideological viewpoints or conspiracy theories. Fallacies are also often easier to communicate than nuanced science and data.

“False cause” relates to the phrase “correlation does not equal causation.” It can be tempting to link coincidences and say that one thing causes the other, but that could very well not be true. For example, more compressors fail during lightning storms. It’s reasonable to assume that lightning causes the failures, but lightning is not simply striking all of the compressors; other power outages and other conditions that happen during storms are more likely plausible causes.

Confirmation bias also makes it easy to cling to a false cause. People are likely to disregard data that doesn’t align with what they already believe.

A strawman misrepresents (or deliberately misstates) another argument to make it easier to attack. People often apply the strawman fallacy to conversations about forming ice in a system during vacuum and duct sizing. Strawman arguments happen more often in business matters, especially if people impugn the intentions of the other party.

In many cases, being open to new information will prevent you from falling prey to logical fallacies.

Nathan and Bryan also discuss:

Flat-earthers
Inverter board failures at night
Evaporator coil corrosion
Simultaneous capacitor and fan motor failures
Logical fallacies in chance and gambling
The pitfalls of anecdotal evidence and small samples
Appeal to emotion
Defining “better”
Mounting TXV bulbs
Heuristics and mental shortcuts

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Tips for Learning in HVAC/R w/ Trevor Matthews Jun 30, 2022

Refrigeration Mentor founder Trevor Matthews returns to the HVAC School podcast to talk about personal development and training, including tips for learning in HVAC/R.

When you’re looking at a problem in the field or in training, it pays to take a step back, cool down, and reevaluate your mindset. Trevor recommends thinking about the worst-case scenario and seeing how you can either prevent it or grow from it. It’s good to walk away for a little bit anytime you feel like you’re overanalyzing anything so that you don’t make blunders.

Trevor has found that reading books is one of the best ways to learn about HVAC/R. HVAC/R professionals can greatly benefit from investing in themselves and setting up their own self-directed training programs. Trainers and mentors can’t be the only ones motivating HVAC/R professionals, holding them accountable, and stimulating their growth.

Many times, our own limiting beliefs of ourselves hold us back, and we need to convince ourselves that we can learn difficult things, even if it isn’t easy. We can also limit our ratio of entertainment to education; focusing more on the latter can greatly benefit your personal development.

Setting educational goals is also difficult when we work long hours and simply don’t have the time or energy to invest in ourselves. The industry needs reform, and reform that raises base rates and prevents an over-reliance on overtime might also attract some new professionals to the field.

Trevor and Bryan also discuss:

Trevor’s new podcast
Clearing your head
Books about doing the hard things first
Autodidactism and “learning how to learn”
Subconscious cost-benefit analysis
The industry’s addiction to overtime
Helpful books and podcasts for personal development
Getting rid of “tunnel vision”

Recommended book/podcast list:

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Threaded Connection Tips - Short #149 Jun 28, 2022

In this short podcast episode, Bryan shares some of his top threaded connection tips. He also clears up some confusion about connection types.

Threaded connections include flare and compression-type fittings (like chatleff or Aeroquip fittings). The threads don’t actually make the seal; the pressure pushing the surfaces together is what makes a seal.

Bryan doesn’t recommend putting traditional thread locks on flares, but refrigerant oil or mild assembly lubricants can help the flare come together more smoothly without imperfections. However, you need to be careful when using a torque wrench and use the lowest acceptable specification to avoid over-torquing.

Leaks are common problems with flare fittings, but those often happen in cases where flares are poorly made. Scored faces, loose flares, and over-torqued flares are common causes of leaks. However, many modern flaring tools can make perfect flares quite easily. You must also remember to deburr the copper for the best results.

Compression-type fittings often have O-rings, which are the parts that actually do the sealing. (Leaks WILL happen without the O-ring in place.) You can use an assembly lubricant with these fittings, but you still have to be mindful of torque spec adjustments.

Pipe-thread connections actually rely on the threads, not pressure or an O-ring, to create a seal. Pipe dopes (or thread sealants) tend to be best on these connections, but you want to leave the last couple of threads bare so that pipe dope doesn’t get into the system.

As with brazed and soldered joints, the copper used for threaded connections needs to be cleaned, cut squarely, and deburred for best results.

Bryan also covers:

Assembly lubricants
Brazing vs. soldering
Zoomlock
IMC 1107.5.4
Protecting seals during brazing and soldering

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Giving Kids The Tools For Any Job They Want Jun 23, 2022

Bryan explains how parents and educators can succeed at giving kids the tools for any job they want. This podcast was originally a presentation at the 2022 FPEA Florida Homeschool Convention.

Jobs, careers, and vocations have changed a lot over the years. Even though those have changed over the years, parents still want their kids’ vocations to develop character, foster growth, and bring joy. While kids are young, parents can instill values of grit and diligence; however, parents have to overcome the challenges presented by the instant gratification provided by technology.

Interest-guided learning is a double-edged sword, as it allows a child to pursue their interests but can cut them off from the interest of others. Developing the values of kindness and deference can temper the negative effects of interest-guided learning while maintaining the benefits of interest-guided learning. If a child has an interest in something and can pursue that interest on their own by demonstrating autodidactism, they open themself up to a lot of vocational options.

Nowadays, it’s a lot more common for people to hold many different jobs or vocations over their lifetime. Encouraging a child to learn different skills allows them to explore non-linear career paths more easily than children who don’t learn useful skills. When teaching children, developing mental models and an appreciation for learning is another key to success across vocations.

Bryan also talks about:

Vocation vs. avocation
Grit vs. talent in the pursuit of success
Modeling and practicing gratefulness
Transferable skills
Feeling “stuck” in a vocation
Visualizing average molecular velocity
Learning about humidity and electrical movement
Striking a balance between joy, service, and passion
Expectations vs. standards
Pursuing college, business ownership, and other career opportunities

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ERV & HRV - Short #148 Jun 21, 2022

In this short podcast episode, Bryan talks about ERV and HRV technologies, including their appropriate applications and limitations.

HRVs are heat recovery ventilators (not to be confused with heat recovery units or HRUs), and ERVs are energy recovery ventilators. The main difference between these two lies in the type of heat they move; HRVs only move sensible BTUs, whereas ERVs move sensible and latent BTUs.

As you bring air in from outside, you’re discharging roughly the same amount of air (though modern technologies allow you to manipulate the pressure a bit more). The goal of the HRV or ERV is to recover some energy from the air exiting the structure and incorporate it into the incoming airstream. The airstreams cross over each other, and there is heat transfer but not air mixing. (ERVs also allow for the exchange of moisture.) Two fans drive the direction of energy flow, and a mesh or a porous desiccant medium facilitates the interaction between the airstreams.

You will get some energy savings with an HRV or ERV, but savings are dictated by the amount of air moved and the temperature differential between the airstreams. In general, you will see HRVs up north (in low-humidity markets) and ERVs down south (in higher latent-heat markets). However, even ERVs aren’t very effective in conditions with low energy transfer and high moisture UNLESS they’re used with a ventilating dehumidifier.

Bringing in fresh air is good for indoor health and safety, as it helps dilute the presence of VOCs, viruses, and harmful gases. HRVs and ERVs help us manage the air we bring in.

Bryan also covers:

Integrating ERVs with bathroom ventilation
Safety considerations to consider for outdoor air
Positive pressurization
Demand ventilation with CO2 sensors
Learning about ASHRAE 62.2

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Refrigerant Changes Coming & The Helix w/ Emerson Jun 16, 2022

Rajan Rajendran and Jennifer Butsch from Emerson join the podcast to discuss the Helix and some refrigerant changes that are coming. Jennifer is the Director of Regulatory Affairs, and Rajan is the Global Vice President for Environmental Sustainability and former director of the Emerson Helix.

Lately, there have been more environmental efforts to reduce greenhouse gas emissions, and plenty of large corporations have “net zero” initiatives. Sustainability requires a holistic, systemic approach in our industry; the Helix Innovation Center conducts the research needed for us to handle these sustainability initiatives as effectively and safely as possible.

However, the sustainability initiatives frustrate a lot of technicians. There will likely be multiple refrigerant transitions as our industry progresses. Education and knowledge provided by manufacturers and HVAC organizations will be the key to smooth transitions.

Many of the replacement refrigerants, including R-32 and R-454B, are A2Ls. These mildly flammable refrigerants have different handling, transportation, and charging procedures than what we’re used to. However, we are unlikely to see changes in oils; POE and PVE oil will likely remain dominant in the market.

Eventually, we may see more GWP changes. We would also be prudent to focus on preventing and rectifying equipment leaks. Proper maintenance will help us navigate current and possible future changes.

Rajan, Jennifer, and Bryan also discuss:

The AIM Act and HFC reduction in 2024
GWP-limit petitions in HVAC vs. refrigeration
Refrigerants that manufacturers are embracing
Refrigerant testing processes
Natural refrigerants
The weight of refrigerants vs. the weight of air
Evaporator coil manufacturing and leakage
Built-in leak detection
Refrigerant pricing

To learn more about these coming refrigerant changes, check out the AHRI Safe Refrigerant Transition Task Force’s resources HERE or Emerson’s E360 Platform HERE.

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Pilot Controls - Short #147 Jun 14, 2022

In this short podcast episode, Bryan talks about pilot controls. He talks about the old-school ignition systems on gas appliances and some similar pilot functions on residential A/C units and heat pumps.

When we think about a pilot light on a gas appliance, we can think of it as a small standing flame that sits there ready to ignite the burner whenever gas is flowing. Pilot lights were necessary for old-school gas furnaces, and many of those pilot lights worked with a thermocouple. In many older furnaces, pilots also prevent excessive carbon monoxide from unspent gas. In other words, the pilot is not the main burner; it merely sets up the main burner.

On a typical A/C system, the 24v power is similar to a pilot on a gas appliance; the 24v “pilot” control energizes the system and has a small amount of voltage (compared to the high voltage needed for all of the components to work).

The reversing valve on heat pumps also has a pilot valve; the 24v signal activates the pilot valve with the solenoid, which redirects system pressure to allow discharge gas to slide the valve. That’s also why you can’t shift the operating mode when the system is off. Solenoid valves in general tend to have pilot functions; they rely on a refrigerant pressure differential that results from 24v electrical signals, not the signal itself.

In short, we don’t rely on the pilot light or the 24v electrical signal to power the entire equipment. Pilot controls merely help the equipment get started; they have less load on them and trigger or control parts and processes that are more complicated.

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Ethics - Grit and Discipline Jun 09, 2022

Bryan and Robert Orr continue their discussion about ethics by talking about what it means to have grit and discipline in business. They talk about what those characteristics look like in business and in life, and they mention some good books.

Grit is a trait that can contribute to an ethical way of life; showing grit means that you follow through with a project until you get the results you want. Both physical and emotional grit are strengths, and those things tend to be more important than talent in our field.

Compared to discipline, grit is a lot more closely intertwined with a person’s emotional condition. When we encounter overwhelming negative emotions, grit is the quality that allows us to power through the current state of affairs. Discipline and grit are both based on commitment and resolve, but discipline deals more with actions rather than feelings. Discipline is more about habits, balance, and wisdom.

A belief system or set of guidance is what drives discipline. Discipline can also be repetitious and boring, but it can take you farther than raw talent if you dedicate yourself to your belief system, sources of guidance, and goals. Developing discipline requires us to establish habits and sequence those habits. Good leaders and parents are the ones who establish those habits for employees or children.

However, something to keep in mind is that both grit and discipline can amplify a person’s bad characteristics.

Robert and Bryan also discuss:

Grit vs. talent (Angela Duckworth)
Does grit count as an ethic?
Discipline and delaying gratification
Developing grit over time
“Real” vs. “true” emotions and thoughts
The downfalls of raw talent
Thinking about obstacles in a healthy way

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Ethics - Integrity Jun 02, 2022

Bryan and Robert Orr talk about ethics and what it means to have integrity when running a family business. Robert is a lifelong tradesman who is a licensed construction contractor, and he has overseen the construction side of Kalos for many years.

Robert initially started off at the Air Force Academy and realized that he didn’t feel that the military was right for him. While in Florida, Robert fell into the trades and learned both hard skills and ethics in the process. He started his own house-wiring business at age 21. Later, he went into home inspection and eventually started a business with his son (Bryan) and his brother-in-law (Keith)

Kalos was co-founded by Bryan, Robert, and Keith, all of whom were tradesmen. Even when naming their business, they wanted to focus on ideals that extend beyond them and their individual legacies. They settled on the name “Kalos,” which is the Greek word for “integrity.”

Having integrity in business is a lot more than just following rules and “having principles.” Real integrity is authentic and honest; you’re transparent about who you are and deliver on the promises you make. Integrity and customer service are NOT the same thing, but you tend to yield higher customer satisfaction if integrity is at the forefront of your business.

Evaluating yourself is also a component of integrity: reflecting on your desires, confronting greed, caring for employees, and choosing to do the right thing. In many small businesses that haven’t fully found their stride, integrity can be compromised by fear.

Robert and Bryan also discuss:

Christianity in business
Integrity as it relates to pricing expectations
What it means to be savvy
Taking responsibility

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Distributors and External Equalizers - Short #146 May 31, 2022

In this short podcast, Bryan talks about distributors and external equalizers and why we need to use them together.

When older Carrier heat pumps (with pistons) would run in heat mode, the metering device would be outside. In those cases, the port on the liquid line would be on the opposite side of the metering device. So, you wouldn’t actually be measuring the liquid line pressure (high-side) if you measured it at that port while the system runs in heat mode.

However, that pressure would be higher than the common suction pressure. That’s because distributors and distributor tubes also have a pressure drop associated with them AFTER the metering device.

Nowadays, TXV systems have external equalizers, which create an equalizing force inside the valve. The bulb pressure forces the valve open, and the equalizer pushes against that pressure to create a closing force. An internal equalizer would work fine on a system without a distributor or distributor tubes; however, those systems are few and far between. We need an external equalizer on systems with distributors because the pressure at the end of the evaporator coil is significantly lower than the pressure picked up by the valve. Without closing force, the TXV would theoretically force itself all the way open and flood the evaporator coil.

External equalizers can get clogged, which results in a pressure buildup during the off cycle and forces the valve closed. They can sometimes get clogged when used on a Schrader port without a Schrader depressor inside the equalizer.

Some people attempt to fabricate distributors in the field. It works in some cases, but in many cases, it’s best to use an engineered distributor for the best performance and efficiency. The distributors are individually designed to create an individual pressure drop.

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Center-Tapped Transformers - Short #145 May 24, 2022

In this short podcast episode, Bryan talks even more about sine waves and center-tapped transformers.

Power is generated at the power plant when an energy source (such as steam) is used to drive a drive shaft. The resulting current can be mapped as sine waves, which actually represent points on a circle; there is a rotational magnetic field around stationary conductors, and the sine waves allow us to envision the positive and negative alternations as the rotation happens.

Center-tapped transformers use “neutral” as a reference point. The secondary winding on a center-tapped transformer may have 240v power, but the center tap splits that 240v power into two legs of 120v power. There are two sine waves completely out of phase with each other, so we get 240v from peak to peak. Both sine waves cross at neutral.

Even though the split-phase power consists of two separate sine waves, an oscilloscope would interpret the voltage as a single up-and-down wave with a higher peak and a lower valley. Center-tapped transformers do not necessarily create another phase of power; they merely turn neutral into a reference. If we were to measure that split-phase power as a single 120v sine wave with an oscilloscope, we would have to use neutral as our reference. To measure the separate sine waves for a total of 240v, we would need three probes: a reference at neutral and one reference on each side.

Many European countries only use a single sine wave; center-tapped transformers are not commonplace in those countries, and neither is split-phase power. However, the split-phase power in the USA allows for more versatility; we can supply power to 120v appliances where we would otherwise need to use 240v ones.

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Beer & Power Factor - Short #144 May 17, 2022

Bryan describes the tricky concept of power factor and why we should care about it. He also compares power factor to a beer mug to make the topic easier to understand.

Power is often represented on a sine wave, which is a curvy line that marks the state of electrical energy at different points on a circle. Power gets stronger and weaker, and it goes above and below the neutral line depending on the excess or deficit of electrons.

Unity power factor refers to a power factor of 1, indicating that voltage and amperage are perfectly balanced; there is no lag. However, an inductance (a form of resistance) opposes the current and causes an imbalance between current and voltage. Power loss or quality refers to the difference between the input and output power that results.

Apparent power refers to volt-amps, which we’d traditionally consider to be the wattage; however, in an inductive load, the true or real power (wattage) accounts for that power loss and comes from volts x amps x power factor. We can imagine power factor as a mug of beer: apparent power (VA) is the entire mug, the foam is reactive power (wasted), and the beer itself is real power. The power company only charges for the real power, not the reactive power. However, a power factor closer to unity can help prevent motor windings or wires from overheating.

To get closer to unity power factor, we need to make sure we have a run capacitor of the correct size. You can measure power factor with a power quality meter.

Bryan also covers:

Voltage and current
Root mean square
Inductive reactance
Capacitance and how capacitors work
Transformer VA ratings

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Motor Speed Facts - Short #143 May 10, 2022

Bryan lays down some motor speed facts in about 10 minutes in this short podcast episode.

We can figure out how quickly a single-phase motor (PSC) will run if we understand how many cycles it will make per second. In the USA, the standard hertz is 60 Hz (60 rotations or magnetic alternations per second). Motors are inductive loads that create an electromagnetic field with a spinning rotor and stationary stator; the amount of poles on the stator determines how quickly the rotor spins (RPM).

In the RPM counts, there are some allowances for slip. Slip varies depending on the load, with excessive loads causing more slip. Some multi-tap blowers have additional winding resistance and decreased current (due to the extra taps), which increase the slip. The rated load RPM usually accounts for the RPM at high speed, not medium or low speed with added resistance.

On the other hand, variable-speed motors or ECMs are powered by a variable frequency (sometimes a variable frequency drive or VFD). The motor control takes the incoming electrical frequency and converts it into a new frequency (turning AC power to DC and controlling the cycle rate). These motors also tend to be more efficient as a result. The RPM is more variable on these motors with VFDs, whereas we could only manipulate the RPM of single-phase motors by changing the number of poles.

When replacing a motor, you can’t use a replacement motor with a higher rated RPM than the original motor. The only way to change the RPM is to get a new motor with a different number of poles, increase slip to make it slower or decrease slip to bring it closer to synchronous speed, or adjust the frequency.

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Value Design in High Performance Home HVAC w/ Comfort Squad May 05, 2022

Neil Comparetto and John Semmelhack of the Comfort Squad join Bryan to discuss high-quality value design in a high-performance home. They explain how they design HVAC systems (heat pumps) for low-load homes in ways that are affordable, efficient, and comfortable.

High-performance, low-load homes need to be energy-efficient AND comfortable, and it can be a challenge to get both. Manual J calculations aren’t as common as they probably should be, and it can be difficult to get accurate data about air leakage, power consumption, and radiant gains as well. So, John and Neil try to collect their own data and do aggressive load calculations to avoid the fudge factors that are all too common. The air velocity inside the ducts tends to be lower in these sorts of systems.

When you have relatively low airflow in the ductwork of high-performance homes, you don’t need as many ducts or for the ductwork to be particularly large. With minimalistic ductwork, supply register placement, face velocity, and throw become very important, especially because those factors are responsible for air mixing. When the duct design conditions are right and the load has been matched, you typically get long runtimes and good air mixing.

In many cases, John and Neil use variable-speed motors in their outdoor units that allow for high heating performance. The capacity ranges are wide, allowing the units to run even during exceptionally low-load conditions. They also use flex ducts due to their pre-insulation, noise suppression, and inexpensiveness; they just try to keep it sealed and avoid compressing the ductwork.

Neil, John, and Bryan also discuss:

Monitoring load conditions with software
Design considerations for filter grilles and central returns
Room pressurization and airflow testing
Transfer grilles
The Coanda effect and curved-blade registers
Vent sizing
Flex duct installation best practices
Duct fittings
ERVs

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Putting Contractor Success First w/ METUS Apr 28, 2022

Lacey Dietz with METUS and Scott Arnold with Rycor HVAC join the podcast to talk about how the industry can start putting contractor success first. They talk about Mitsubishi Electric (METUS)’s commitment to contractor success and what that looks like.

METUS’s contractor program aims to provide training, support, and recognition to create a community of successful contractors. Support comes in the form of marketing, training, tech support, and customer service, and those services are available to contractors who sell and represent Mitsubishi’s products.

As a contractor who works with Mitsubishi, Scott has been able to specialize the labor in his business and grow his business as one that specializes in installing Mitsubishi systems. Mitsubishi also provided top-quality training and allowed Scott to streamline his training process and get his apprentices feeling confident and ready to go into the field quickly.

Adoption rates for Mitsubishi’s ductless technology have increased over the past couple of years, especially as people have spent more time in their homes and started re-thinking indoor comfort. Those who are educated about heat pumps also tend to appreciate the technology as well as the mini-split units’ small footprints in their homes. The mini-split units’ smaller environmental impact than unitary systems is also a plus.

Lacey, Scott, and Bryan also discuss:

Scott’s work with heat pumps in New York
Programs that benefit contractors
Mitsubishi’s products and supply chain management
Diamond Contractor program and tiered contractors
Mitsubishi’s lead generation program and referrals
Ductless vs. unitary systems
Bringing education into sales
Dealing with business growth in a challenging labor market
Overcoming objections

Learn more about Mitsubishi and its products, visit https://www.mitsubishicomfort.com/, and you can learn how to become a contractor at https://discover.mitsubishicomfort.com/contractors.

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Retrotec - IBS 2022 Apr 26, 2022

Sam Myers with Retrotec talks to Bryan about pressures in the home and why they matter for HVAC solutions at IBS 2022.

Technicians focus a lot on ductwork and airflow, but many of them don’t focus on how the building envelope impacts HVAC performance. A lot of the HVAC equipment’s performance is affected by the push and pull of air caused by leaky areas in the building envelope.

If you have a room with too much air and another room with too little, you will have unbalanced pressures. Unbalanced pressures may result in discomfort and latent load issues, especially when unconditioned air is pulled in through the attic. Sealing the envelope well and using dampers as necessary can minimize the comfort issues caused by pressure imbalances in the home.

Instead of just using manometers for static and gas pressure, we can also use high-resolution manometers under doors to pick up pressure differences. However, the manometer MUST be high-res to pick up those subtle (but palpable) differences in pressure. A blower door is also a great tool, especially when you use it with a thermal imaging camera; the blower door amplifies the temperature effects that a thermal camera will detect, especially if you also have a good delta T.

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Birmingham training class Apr 21, 2022

This podcast is a class that Bryan taught for BTrained in Birmingham, AL. He covers troubleshooting, installation, and commissioning best practices with a focus on the fundamentals.

To be a good troubleshooter, you must be able to find the problem, identify the source of the problem, fix the problem, and optimize performance based on your data, the customer’s comments, and your observations. The Five Pillars of diagnosis aren’t comprehensive diagnostic or charging criteria, but they can help you charge or diagnose a system.

Isolation diagnosis works best for electrical components; you isolate the problem area from the system and see how the system works without the suspected issue. If the system operates normally without the component in question, then we can conclude that our hypothesis about the “problem” part was correct.

Wide-narrow-wide troubleshooting is an approach that allows you to inspect the entire system, zero in on the problem, and optimize the entire system. By starting wide, going narrow, and going wide again, you can troubleshoot holistically.

Installations take place in several phases: pre-planning, planning, demo, installation, and commissioning. Many people place a lot of emphasis on the demo and installation and neglect the conversations and procedures associated with pre-planning, planning, and commissioning.

Bryan also covers:

Heuristics and mental shortcuts
Evaporation vs. boiling
Rules of thumb
Head pressure, suction pressure, and compression ratio
Energy transfer fundamentals
What superheat and subcooling really indicate
Restrictions and temperature drop
Delta T
“Redneck” compressor test
Testing circuits
Useful measurements and test instrumentation
Causes of compressor failure
Measuring airflow
Low vs. high static pressure
Bringing tribal knowledge to building design
Ductless systems, ventilating dehumidification, and sensible heat ratio
Manual J, attics, and combustion air
Radiant barriers and heat transfer
Supply relative humidity
Dehumidifier configuration and system design
Bad envelopes
Vented attics
Duct upgrades
Total effective length and turning vanes
Evacuation

Learn more about BTrained at https://btrained.net/ or on the BTrained YouTube channel at https://www.youtube.com/channel/UCnlDsWHT68gVwPrYYO5vhrw.

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Ross Trethewey IBS 2022 - Short #141 Apr 19, 2022

Bryan has a bit of an industry nerd out with Ross Trethewey from “This Old House” and TE2 Engineering at IBS 2022 (the International Builders’ Show). Ross’s education and career have focused on mechanical engineering, especially with sustainable solutions.

In building science, the key mindset is to think of the building as a system. Using that school of thought, Ross has developed building science and HVAC solutions that also consider indoor air quality and ventilation, such as hybrid VRF systems.

Many of Ross’s solutions take the best aspects of air-source and ground-source heat pumps and apply those to hydronics. Some exciting applications for those types of systems could include simultaneous heating and cooling as well as the integration of domestic hot water.

Demand control ventilation has been used for a long time in the commercial world, but its possible use in residential applications is another exciting thing to consider. With proper control devices, DCV would give us the opportunity to control temperature, humidity, VOCs, carbon monoxide, carbon dioxide, and radon. In residential applications, DCV has to be a delicate balancing act, as bringing in too much outdoor air would require us to condition that air. High latent loads also present challenges to some of the ventilation solutions in development.

Serviceability is another challenge to DCV usage in residential applications; whenever an innovative system is brought to the market, very few people will know how to fix and maintain those systems. One of the possible solutions is to create instruction manuals and give education similar to what already exists for package units. 3D models and animations also help make complicated systems easier to understand.

Ross’s presence on “This Old House” marks the third generation of Tretheweys on the show. Ross is excited to talk about building science and HVAC innovations and concepts while on the show.

Heat pumps are also getting better, especially due to inverter-driven compressors, enhanced vapor injection, advanced control systems, and ECMs. Heat pumps are safer than gas-fired equipment, and we have made them work well in subzero temperatures (because we’re nowhere near absolute zero).

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Replacing a Compressor - Step by Step Apr 14, 2022

In this podcast, Bryan goes through the entire process of replacing a compressor step-by-step. This process is what the Kalos team uses to replace a failed compressor and make sure it doesn’t fail again.

Before replacing a compressor, you must figure out how the compressor failed; grounded conditions often lead to acid, so it’s a good idea to test for acid and see if you need to address a burnout. In any case, make sure you have the correct tools for the job (including a compatible replacement compressor).

When you arrive at the job site, be sure to confirm the diagnosis and check to see if the unit has a hard start kit. That’s also the time to do a visual inspection, checking airflow as well as the filter, blower, and coil cleanliness. Recover and weigh out the refrigerant charge.

Unscrew the foot bolts and lift the old compressor out. Then, seal the compressor once it’s out. If you’re dealing with burnout, clean out or replace the accumulator (you will install/reinstall it shortly). Cut out and replace the existing liquid line drier and install a suction drier in a place where it can be easily removed.

When piping in the new compressor, make sure you protect heat-sensitive parts and do a quality brazing job. Install the new capacitor and hard start kit, too, keeping wiring away from places where it may chafe.

Test for leaks, evacuate the system, charge the system, and check your five pillars as well as voltage. Finish by cleaning the drain and double-checking airflow.

Bryan also covers:

Misdiagnosed compressor failure
Parts needed for replacing a compressor
What makes a compatible replacement compressor?
Billing and pricing
Alloys and fluxes
Replacing TXVs, capacitors, contactors, and reversing valves
Cutting vs. unsweating
Suction driers and pressure drop
Charging considerations

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Refrigerant Top off, Drop in and Retrofit - Short #140 Apr 12, 2022

In this short podcast, Bryan explains what it means to top off, drop in, and retrofit refrigerants. He describes the differences between those three things to dispel some of the confusion they may cause.

Topping off a system means that you add refrigerant to a low existing charge to get it back up to a normal level. In some cases, people top off systems with dissimilar refrigerants (e.g., topping off R-22 systems with cheaper R-407C). Topping off a system with a dissimilar refrigerant is unacceptable, as it’s against EPA guidelines and leaves you with an undefined refrigerant mixture. You’re only supposed to top off a system with the same refrigerant that’s already in it.

High-glide refrigerant blends can be tricky to top off when there is a leak, as one refrigerant type may leak more quickly than the other and leave you with a different chemical profile. So, you’re better off recovering and starting over when you have lost a significant amount of charge to a leak.

If you want to recharge an entire system by recovering the existing charge, you would instead be using a “drop-in” refrigerant. There are no drop-in solutions for R-410A systems. However, some commercial equipment manufacturers can offer information about drop-in solutions, though they are relatively rare, especially as oil has changed over the years. When you drop in refrigerant, you don’t have to change O-rings, Schrader cores, or other components. Drop-ins are NOT necessarily like-for-like when it comes to charging.

“Retrofit” is a relatively broad term that refers to any type of refrigerant change. The retrofitting practices that may have worked for A1 CFC systems to A1 HCFC systems will NOT work for A1 to A2L refrigerants. We need new installations for flammable refrigerant systems.

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The Value of Networking for Techs w/ Trevor Apr 07, 2022

Trevor Matthews, the founder of Refrigeration Mentor, is back on the podcast. This time, he and Bryan talk about the value of networking for HVAC techs as the conference season comes to a close.

Many trade events are networking opportunities that allow you to build relationships with other tradespeople, educators, mentors, and even other companies. You can also learn many trade and business tools that help you as a technician. Many technical and business conversations occur at trade events, and there is a lot to learn from those, whether you’re directly involved or just listening. It can also be useful to sit in on classes or presentations about topics that you don’t directly deal with, such as building science.

Networking also has value for technicians because it can provide several means of personal development. Making connections with potential mentors can open the doors to new career opportunities, even in places where you wouldn’t have expected yourself to work.

If you see someone you want to talk to at an event, feel free to go up and talk to them. Trade events are places where people expect to get to know one another, so many of the people who attend them genuinely want to talk to others in the trade. People like Trevor are happy to share their knowledge and help you develop yourself as a technician. You can also send people emails introducing yourself to them before the event if you’re a bit introverted and uncomfortable putting yourself out there.

Trevor and Bryan also discuss:

Being isolated in a “bubble”
Choosing to work or visit conferences
Networking to avoid getting stuck
Planning trips around trade conferences
The 2023 HVACR Training Symposium
Specialized conferences
Refrigeration Mentor

Learn more about Trevor’s work at https://refrigerationmentor.com/.

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How to EFFECTIVELY implement educational growth w/ David Richardson Mar 24, 2022

David Richardson of NCI joins the HVAC School podcast to talk about how we can implement educational growth effectively throughout the trade. NCI started as a premium training resource about airflow testing, but the organization eventually started teaching about combustion testing as well.

When we improve the industry, we need to be able to have concrete ways to see what we’ve been doing wrong or what we can do better. Test instruments allow us to see the whats and whys behind what we do. Education needs to be focused on bringing those test instruments into training AND teaching others how to use them properly.

Once we find a way to understand the invisible aspects of what we do, we can get into systems thinking and grasp the more abstract concepts much more easily. When people are introduced to concepts in a logical sequence, they can build their knowledge on what affects the system and why it does do.

When we tie everything together, including using solid data, testing in and testing out, and using sources to help you interpret data, we can implement educational growth more effectively. Most of all, we can learn how to translate the technical into practical, which helps us communicate with the customers in ways that matter.

However, the most important thing about test instrumentation and applying it to learning is understanding why you are doing those tests or why you want to do them.

David and Bryan also discuss:

The purpose of traverse tests
The mechanics of NCI’s teaching (PATH to performance)
To charge or not to charge for combustion analysis
What NCI does and how to get involved with NCI

Learn more about NCI or get involved with their training at https://nationalcomfortinstitute.com/.

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Comfort Investigation on TV w/ Corbett Lunsford Mar 20, 2022

Corbett Lunsford of Home Diagnosis joins Kaleb to record a podcast about comfort investigation on TV. The two of them discuss how comfort investigation works on TV shows, what Home Diagnosis hopes to accomplish, and some building performance tips.

Home Diagnosis is mostly aimed at homeowners, but HVAC technicians would also benefit from the show, as it dives into science and testing. The show promotes consumer education and contractor accountability.

Diagnostics and testing are absolute MUSTS for providing the best possible solutions and transforming your business. You put yourself in another league when you take measurements and have the data to create tailored solutions. In other words, you can’t manage what you can’t measure, and if you’re not testing, you’re guessing.

The current paradigm shift in the industry has to do with custom designs. Physics, chemistry, and microbiology are all important facets of applied science to consider when coming up with a custom solution. Many buildings have distinct microbiological profiles, including bakeries with yeast or cheese production or aging facilities. Natural events and human activity can change these buildings’ microbiological profiles.

Ventilation is part of the equation of home performance, and it’s a pretty delicate one that HVAC techs can control. When it comes to ventilation, we would be wise to avoid selling products we don’t understand. Ventilation solutions may also be appropriate for one structure but inappropriate for another, so we need to think about the applications of these solutions.

Corbett and Kaleb also discuss:

Comfort vs. efficiency vs. control
ERVs vs. HRVs and humidity
How the market influences custom solutions
Preview of challenges in Season 3 of Home Diagnosis
Microbiology of structures

Learn more about Home Diagnosis at https://homediagnosis.tv/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Commercial HVAC Predictive Control w/ BrainBox AI Mar 17, 2022

Blake Standen and Omar Tabba of BrainBox AI join the HVAC School podcast to talk about commercial HVAC predictive control. This conversation focuses on applying artificial intelligence to existing building systems, including the HVAC, to predict performance under certain weather and occupancy conditions. If you have controls that can predict performance and adapt, then you can maximize energy savings.

A commercial HVAC system may include air handlers, chillers, boilers, RTUs, and all sorts of energy-consuming technologies. These systems also have controls that help direct the infrastructure, and artificial intelligence can help optimize the controls, make performance predictions based on forecast data, and make those controls communicate with foreign controls from other companies (such as via BACnet).

BrainBox AI uses a cloud to collect and hold the data it needs to predict what a building will do and help control the infrastructure. Controls react to errors, and the goal of BrainBox AI is to predict errors before they happen. For example, AI can help solve short cycling under certain weather conditions. However, buildings that use pneumatics rather than digital controls and older systems may not be good candidates for AI solutions.

One of AI’s challenges is that it requires multiple layers of training: you’re training the controls engineers, facilities staff, AND the AI itself. Another challenge of AI is that people don’t fully understand that it’s not the type of automation that takes people’s jobs; we can minimize those perceptions with education.

Blake, Omar, and Bryan also discuss:

Machine learning vs. artificial intelligence
Accuracy of prediction models
Virtual testing environments
Apathy as a challenge
What happens when controls go offline or are adjusted?
Tethered services
Application programming interface (API)
Controlling comfort and energy consumption vs. greenhouse gas emissions
BrainBox’s global partnership with ABB

Learn more at https://www.brainboxai.com/.

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3 Phase Energy Savings w/ Falkonair Mar 16, 2022

Chris Micallef, the CEO of Falkonair, joins Nathan Orr at AHR to discuss energy savings for three-phase equipment. They also explore some of Falkonair’s controls for compressors, especially on DC inverter equipment.

Falkonair has software that allows users to control all types and brands of three-phase compressors with compatible variable frequency drives (VFDs). The software recommends the compatible VFD based on the amperage readings. Falkonair aims to bring this software to the refrigeration industry and then move on to HVAC contractors and data centers.

The control unit adjusts the compressor speed to respond to changes in refrigerant charge levels (based on discharge temperature). These controls protect the compressor and maintain efficiency, even under less than ideal operating conditions. Energy efficiency can increase by 35% with Falkonair’s control units in place. You can expect longer runtimes, a reduction in short cycles, and a reduction in humidity.

If the refrigerant loss is too great, then the control can also shut down the compressor. However, it should take less time for a facility manager to notice that refrigerant loss is happening. The controls use temperature probes, so they don’t cut into the refrigeration circuit.

Although VFDs are good for reducing vibrational wear and tear, we have to be aware of potential issues with harmonics. Harmonics can damage the bearings, especially on pumps that don’t have oil constantly lubricating the bearings.

Chris and Nathan also discuss:

VFD sizing considerations
How Falkonair’s AI works with hot gas bypass
Software commissioning
Oil return sequences on DC inverter systems
Hertz ranges and limitations per compressor type
How Falkonair’s control units can exceed 35% efficiency gains

Learn more about Falkonair at https://falkonair.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Internal Apprenticeship w/ Brynn Cooksey Mar 15, 2022

Brynn Cooksey joined Eric Kaiser for a podcast about internal apprenticeship, its benefits, and how to make it work. Brynn is the general manager of Air Doctors Heating and Cooling LLC, a well-respected HVAC contracting company in Detroit, MI.

Air Doctors Heating and Cooling LLC has its own in-house apprenticeship program based on Department of Labor guidelines. The apprenticeship program caters to new techs out of trade school and focuses on rigorous training. There is some administrative paperwork, but there are no additional administrative expenses. The only expenses of the apprenticeship program come from training and wages. Most of the administrative work comes from recordkeeping.

Bumps in pay come with milestones, and RSES certification is available at the highest level of Brynn’s program. Once techs receive their RSES CM, they become official journeymen and continue to learn more about the trade through incentivized training.

The technicians at Air Doctors seem to like the training program. The program is very structured when it comes to training, hours, and pay, so the techs like predictability. Reduced callback rates are positive effects of the apprenticeship program; Brynn’s current callback rate is less than 1% (was 3% before the program was put into place).

The apprenticeship program is easy to set up with the government, and it makes companies eligible for national and local grants. Approved apprenticeship programs can also take advantage of other benefits, including labor scouting to grow the workforce.

Everything about the apprenticeship program recognition process was free. Many businesses can take advantage of these programs to grow their workforce and train promising technicians who can transform the business.

Email Brynn for more information at brynn.cooksey@airdoctorshvacservice.com

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New Educational Options w/ Faraday Mar 13, 2022

Alex and Nicole of Faraday join Kaleb Saleeby and Ty Branaman to talk about new educational formats and options in the HVAC industry. Alex is the founder of Faraday, and Nicole is the head of operations. Ty is a notable HVAC educator who supports Faraday and its mission.

Faraday is a free educational program that prepares apprenticeships for fieldwork, allows them to get EPA 608 certification, and helps place them in jobs with paid training. Although the program is free, there is a rigorous selection process to make sure only the most serious candidates join the program. The human aspect is very important to training, and Ty is one of the people who brings that to education programs.

HVAC training is multifaceted, and the appliances are just the beginning. Training focuses on science and math as well as craftsmanship, which isn’t what a lot of people think about when they think of HVAC. Faraday focuses on bringing the abstract and artistic concepts of the trade to training. However, Faraday also acknowledges just how important skills are to a person’s career and life in general.

Faraday also has live sessions with guest speakers, and these are available to current students and alumni. Lifelong learning and investment are important to Faraday, and the programs create a support system for students even after completion.

Alex, Nicole, Ty, and Kaleb also discuss:

Faraday’s admissions process
Ty’s contributions to education and the industry
Bringing the Masterclass format and delivery to HVAC
The ambitions, interests, and fears of young people
Costs of training
Using Discord for communication and training
Teaching life skills
Faraday’s vetting, coaching, and weed-out processes
Producing coachable, well-rounded individuals

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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HVAC Social Media, AHR & AMRAD Capacitors w/ HVAC_ASH Mar 10, 2022

Ashley (aka hvac_ash) joins the podcast to talk about how HVAC fits into social media, AHR 2022, and AmRad capacitors. Ashley works with Global the Source on the sales and distribution side of the business.

Becoming an HVAC influencer is smart, especially when there is a dedicated audience in the industry. When you gain traction online, that can branch into marketing, which helps get the word out even more. It’s also a great way to make connections organically once you have traction and learn from others’ industry-related content.

Ashley also has firsthand experience with the HVAC trade’s obstacles for women. She believes that making groups like Women in HVACR more marketable and focusing on recruiting young women will help break those barriers down. There needs to be more effort to the recruiting process than just posting ads and job postings on social media.

Global the Source is a distributor of AmRad products, including the well-known American-made capacitors and Turbo line of start capacitors (Turbolytic) and hard start kits (TES5). The quality of the AmRad capacitors’ foil and the oil has been tested widely, even on the HVAC School YouTube channel; the conclusion is that AmRad capacitors are made of high-quality materials and last longer than many others.

Ashley and Bryan also discuss:

What it means to be a master distributor
Being an HVAC influencer on Instagram
Visiting AHR as an influencer and sales professional
Strategic recruiting for underrepresented demographics
AmRad’s Turbo product family
New AmRad products for failed run capacitors and stuck relays

Follow Ashley on Instagram (hvac_ash) and DM her with questions or email her at ashleyl@globalthesource.com. Learn more about Global the Source and some of the AmRad products at https://globalthesource.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Net Zero HVAC w/ Bill Spohn, Eric Kaiser and Kaleb Saleeby Mar 10, 2022

Bill Spohn joins Eric Kaiser and Kaleb Saleeby at AHR 2022 to talk about his experiences designing and living in a home with NetZero HVAC.

NetZero HVAC refers to system design with tight coordination with the house to make it as efficient as possible. Some of these systems are so tight and efficient that they approach passive house standards (0.6 ACH50). Bill lives in a modular home that also generates more energy than it consumes, and it doesn’t rely on natural gas.

The greatest expenses of Bill’s NetZero home came from all the custom factors, as it didn’t make sense to price many of the features on a square-foot basis. The heating and cooling system is also unique, as it is completely separate from the ventilation system, which is a Build Equinox CERV. On the IAQ side, the CERV monitors outdoor temperature and humidity, indoor CO2, and indoor VOCs. Bill also has a HAVEN central air monitor inside the CERV system as a backup.

Bill’s HVAC system is an air-source heat pump that provides two tons of heating and cooling and has low-temperature capabilities. The two-ton unit works for a 4400-square-foot home.

Bill, Eric, and Kaleb also discuss:

Energy independence
Controlling radiant heat gains and window construction
Construction and material fabrication
Monitoring energy usage
Energy recovery ventilation (ERVs)
Thermal bridging at work in Bill’s walls
Knowledgeable customers
Jim Bergmann’s help with troubleshooting
Radon issues
Bill’s podcast
Solar inverters
Measuring tool accuracy

You can learn more by listening to Bill's podcast, Building HVAC Science. You can subscribe to the podcast on any podcast app of your choice or get an overview at https://buildinghvacscience.libsyn.com/.

You can also check out Bill’s blog at https://spohnhome.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Data Logging w/ Collin Olson and Eric Kaiser Mar 09, 2022

Collin Olson, the staff physicist of The Energy Conservatory (TEC), joins Eric Kaiser at AHR 2022 to talk a bit about data logging.

Data logging refers to the act of using sensors to record data over time and then analyzing that data. TEC dipped its toes into data logging with the APT and then TECLOG. Data logging allows us to take and store multiple readings as well as extrapolate data into graphs, making it easier to analyze performance. The TECLOG4 software is the most up-to-date version.

TECLOG is a simple software to use with basic training. The understanding of building science continues over a lifetime, but the actual software can be learned in approximately 30 minutes. TECLOG is free with TEC’s hardware, such as the DG-1000. To get started, all you need is a precision manometer and a computer.

However, it’s worth nothing that the DG-1000 stores a lot of data, meaning that you can launch data logging sessions on the gauge without your computer.

Some of the most important measurements are related to drafts and backdrafting. There are 250 Pascals in an inch of water column, and the DG-1000 can pick up very small changes in the Pascals and can indicate when depressurization happens and when it poses a risk. Improperly installed vents can also produce alarming drafting conditions due to air density; data logging can pick up that sort of information.

Collin and Eric also discuss:

The history of TEC’s APT
Wind and its effect on building pressures
Event markers and hotkeys
The link between depressurization, flue gases, and weather conditions
Managing multiple blower doors at a time

Check out TEC’s software, including TECLOG4, at https://energyconservatory.com/downloads/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Unique K-12 HVAC Incentives, Commercial Regulation Changes and More w/ Mark Tozzi from Carrier Mar 08, 2022

Mark Tozzi from Carrier comes on the HVAC School podcast to talk about unique HVAC incentives in K-12 schools.

When schools closed down during COVID-19 lockdowns, a new series of incentives came out for schools. Many of these incentives include access to technology, and improvements to HVACR equipment are covered under those programs.

Schools can benefit from geography-tailored solutions, including air-cooled chillers in the Southeast and products meant to improve IAQ, including filtration upgrades and dehumidification strategies.

To provide valuable solutions to schools, HVACR professionals and manufacturers need to get involved in local conversations, such as on school boards or at the district level. The incentive is quite broad, and it provides schools AND HVACR professionals with many opportunities. The funds need to be spent by 2023, so we can focus on doing business with schools this year.

However, as we seize these opportunities to help our communities, we also need to make sure that we have the labor, training, and ambassadorship to make these initiatives successful. As an industry, we need to focus on recruitment and training to stimulate interest in the industry. Not to mention, as equipment advances, technicians need to be able to catch up with newer technology.

The COVID-19 pandemic has put our industry into the spotlight, and people are paying more attention to their air quality and our work than ever before. Through community opportunities, recruitment, and education, we can hope to improve our industry.

Mark and Bryan also discuss:

OptiClean air scrubbers
Buy boards
How the HVAC industry might appeal to younger generations
When are HVAC contractors seen as valuable to the general public?

Learn more at carrier.com.

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Changing HVAC Regulations w/ Chris Forth of Johnson Controls Mar 06, 2022

Chris Forth, the VP of regulatory codes and environmental affairs at Johnson Controls, joins Bryan for a live podcast at AHR 2022. This time, they discuss changing HVAC regulations and what that will mean for contractors, technicians, and installers.

Johnson Controls focuses on institutional chillers, controls with digital platforms, air handlers, filtration, and alarm systems. Lately, Chris has gotten the industry ready to convert existing products and systems to high-efficiency equipment for low-GWP, A2L refrigerants.

The transition to A2L refrigerants will be different from the transition from R-22 to R-410A. We needed to change the oil type (mineral oil to POE) and make equipment for different pressures when we went from R-22 to R-410A. However, the pressure and oil needs of A2L refrigerants are very similar to R-410A; the main obstacle is dealing with mild flammability.

Every six years, the U.S. Department of Energy (DOE) sets minimum efficiency standards, and they determined that it’s time for an upgrade. In other words, 14-SEER straight-cool A/C systems will no longer cut it in some places. In the Southeast, equipment that doesn’t meet the new standards must be INSTALLED before 2023. (In other cases, the date of manufacturing is what matters.)

Now, contractors need to be sure that they can install 14-SEER units before 2023 if they order them. Otherwise, contractors may be better off ordering 15-SEER units now to ensure that they can install the equipment.

Chris and Bryan also discuss:

North vs. south efficiency ratings
AHRI match
How manufacturers will be affected by these regulations
American Innovation and Manufacturing Act (AIM Act)
The self-extinguishing properties of A2L refrigerants

Learn more about Johnson Controls at https://www.johnsoncontrols.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Control Over IAQ w/ Kevin Hart from Haven Mar 03, 2022

Kevin Hart, the CEO of HAVEN, joins Kaleb Saleeby live from AHR 2022 to discuss how we can control IAQ with central air monitors and controllers. HAVEN, formerly TZOA, is an IAQ company that focuses on protecting building occupants’ health by controlling air quality.

HAVEN’s approach to managing IAQ starts with collecting data about the air. Without that data, we can’t come up with solutions tailored to individual buildings. We need sensors to gather that data, which would traditionally mean that we’d need a decentralized system with sensors everywhere. However, HAVEN takes a centralized approach to measuring and controlling indoor air quality.

HAVEN’s central air monitoring system is not an ordinary box product. Monitors constantly provide data that help HVAC professionals find points of improvement in a home and form a solid professional relationship with homeowners. The goal is to use data as a bridge to connect the homeowner and contractor as well as build trust.

One of HAVEN’s new projects is to expand into remote HVAC diagnostics. The search for deviations in heating, cooling, and comfort will allow HAVEN to get more involved in the HVAC industry and communicate diagnostic help and solutions more effectively.

Kevin and Kaleb also discuss:

HAVEN’s name and vision
Avoiding false positives for harmful substances with centralized monitoring
Equipment longevity
Stagnancy of air in homes in moderate climates
The issue with constant 50% relative humidity
Outdoor air quality and comparative analysis
IAQ as a luxury rather than a necessity
Predictions for the HVAC industry

Learn more at https://haveniaq.com/ or become a HAVEN Pro today at https://pro.haveniaq.com/.

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A FASCINATING New Power Generation / Water Heating Solution w/ Enginuity Mar 02, 2022

Jacques Beaudry-Losique, the CEO of Enginuity Power Systems, joins Nathan Orr live at AHR 2022. Enginuity manufactures energy-efficient engines that produce more power than traditional engines and recover waste heat to act as water heaters. Enginuity engines can run on propane and natural gas to help you run almost entirely off the grid and participate in electricity buyback programs. These units operate independently of the electrical grid and can act as generators during power outages and have a small footprint. However, a backup battery system is recommended for these units to maximize efficiency. Enginuity has a residential and commercial line. The E | ONE is best suited for residential applications, and the E | TWO is better for heavier commercial applications. The U.S. Army has been one of the most prominent supporters of Enginuity, which also manufactures its units exclusively in America. Distribution is done through a third party, including business owners and technicians; Enginuity doesn’t deal directly with homeowners or building staff. As a result, A/C service technicians, installers, plumbers, and refrigeration technicians may end up being the people in the middle who do maintenance on Enginuity generators.

After this conversation with Jacques, we are very interested in seeing what the future holds for Enginuity and combined appliances.

Jacques and Nathan also discuss:

The electrical grid’s stability
Enginuity’s revolutionary piston design
Ease of startup and commissioning
Pricing questions
Enginuity’s target market and training resources for that target market
Engine life expectancy
Enginuity’s projected rollout timeline and expansion plans
Decentralizing power dependence
Solar vs. fossil fuel energy
The problem with power plants

Learn more about Enginuity at https://enginuitypowersystems.com/.

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Samsung Ductless LIVE From AHR - Short #139 Mar 01, 2022

Rick Nadeau, Director of Training and Technical Services at Samsung, talks with Kaleb Saleeby live from AHR. He explains some of the exciting ductless solutions that Samsung has to offer.

Samsung’s WindFree mini-split systems work with VRF systems or as normal ductless units. The WindFree product line is best known for preventing drafts due to microholes. These systems come in one-way and four-way cassettes and work very well for sensitive environments like nursing homes and bedrooms.

These units also have humidity sensors that let the units know when it would and wouldn’t be acceptable to go into WindFree mode. Samsung’s systems may also have occupancy sensors, which determine when they can turn on to provide comfort and flexibility. The systems also have the capability to determine when the system is losing refrigerant to prevent major environmental and performance issues.

Samsung has MaxHeat technology, which allows a system to have 100% heating capacity in low-ambient temperatures as low as -30 degrees Fahrenheit. So, the lack of reliance on auxiliary heat can reduce energy consumption and costs under most conditions.

In general, much of Samsung’s innovative technology is introduced across entire product lines.

In the commercial sphere, Samsung’s DVM S is an influential modular chiller and water heating system. Its flexible design (thanks to VRF technology) has made it a popular choice for product storage in vineyards. The DVM S Eco also has heat recovery capabilities.

Rick and Kaleb also discuss:

Stratification prevention and high-ceiling configurations
Air velocity and unit cleanliness
Refrigerant loss detection

Learn more about Samsung’s ductless systems and online training programs at https://www.samsunghvac.com/.

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How to ACTUALLY Measure Airflow w/ Steve Rogers and Eric Kaiser Feb 27, 2022

Steve Rogers from The Energy Conservatory (TEC) joins Eric Kaiser to talk about airflow measurement at AHR 2022. Steve is an expert in fluid dynamics and flow measurement, and he is a trainer in addition to being the president and CEO of TEC.

Airflow is one of the most critical elements of an HVAC system; it allows us to move the correct amount of BTUs to condition the air properly. We have various ways of measuring system airflow and airflow to a space. We can use the TrueFlow grid for the former and flow hoods for the latter.

When it comes to measuring airflow, calibrating the instrumentation is crucial. TEC uses a laboratory-grade orifice plate to calibrate the tools. So, the calibration process manages to yield high accuracy while using a low-maintenance device.

To begin measuring airflow properly, start taking the total external static pressure (TESP) and looking at fan charts. TESP doesn’t actually measure airflow, but it provides an idea of what the airflow might be like, and it’s a practical, useful measurement in the field.

The TEC TrueFlow grid has recently been upgraded, and it’s a good step up from taking the TESP and referencing fan charts. It goes into the filter slot and measures the CFM per ton as well as the static pressure.

Steve and Eric also discuss:

Airflow’s effect on latent and sensible cooling
Blower door setups and chambers
References for accuracy
Relationship between static pressure and airflow
Is the hand-ometer an acceptable form of airflow measurement?
Challenges of pitot tubes and hot-wire anemometers

Learn more about The Energy Conservatory at https://energyconservatory.com/.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Commercial Rack Refrigeration Component Identification Feb 24, 2022

Brett Wetzel and Kevin Compass from the Advanced Refrigeration Podcast join us to discuss commercial rack refrigeration and identify components.

In supermarket racks, we typically have anywhere from 2-5 compressors on a single rack (with multiple evaporators, metering devices, and sometimes even condensers). These compressors may come in several varieties (including screw and scroll) and be digital or have VFDs. They also have common suction and discharge headers.

The compressors all share oil from a single system. Oil separators can come in three varieties: centrifugal, impingement, and coalescing (most efficient). The separator would feed into the reservoir, which stores oil.

Many rack systems use several different valves. Check valves to direct the refrigerant flow, especially on heat reclaim systems and split condensers. In some cases, there is a three-way valve or a solenoid valve that controls or stops the refrigerant flow. LDR (liquid differential regulating) valves maintain the required differentials during defrost. Ball valves can be found all over a rack (liquid line, suction line, discharge line, etc.) and can isolate a line. Standard and balanced-port TXVs or EEVs may also appear on racks. There is also an EPR, which controls evaporator temperature and pressure.

Grocery systems have a drop leg before the receiver, which stores liquid refrigerant. We want a full column of liquid leaving the receiver, which we can confirm with a sight glass rather than subcooling.

Brett, Kevin, and Bryan also discuss:

Reheat and excess heat
Split condensers
Drain leg/drop leg vs. liquid line
Mechanical subcooling and heat exchangers
Counterflow piping
Hot gas vs. Kool gas defrost
Standard vs. balanced-port TXVs
Distributors
Evaporator fin spacing
Cleaning components

Check out the Advanced Refrigeration Podcast on any podcast app of your choosing.

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Universal Boards and Controls w/ Eric K. and Jim F. LIVE from AHR Feb 23, 2022

Jim Fultz from Emerson joins Eric Kaiser at AHR to share his knowledge of universal boards and controls. Jim’s work focuses on electronic controls within the White-Rodgers brand.

Common White-Rodgers universal controls include the SureSwitch and universal defrost controls. The SureSwitch also has sealed contacts, which prevents insects and debris from shorting out the contacts.

This past year, White-Rodgers debuted the All-Spark, which doesn’t need electricity to be powered up and can be programmed right out of the box. The All-Spark works on all sorts of appliances, not just boilers and furnaces.

Universal controls are generally safe to put in combustion units, even gas furnaces. New controls go through rigorous testing before they hit the market. The controls MUST stay within the OEM’s guidelines; otherwise, they won’t make it to the market. Sometimes, when boards need to be replaced, we also need to upgrade the igniter to match the voltage of the new board.

The goal of universal controls is to save time and hassle for the technicians and the customers, which makes it easier to make sales. It’s also easier for the distributor to get fast and accurate solutions to the technicians, especially when OEM parts may not be immediately available due to supply chain issues and normal shipping expectations.

Jim and Eric also discuss:

All-Spark benefits and features
Manufacturer-specific vs. general universal controls
White-Rodgers nomenclature
Controls instructions
Distributors and sales reps
Evolution of controls for direct-spark and hot-surface ignition
Training techs to install controls on equipment

Learn more about White-Rodgers controls at https://climate.emerson.com/en-us/brands/white-rodgers.

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Malco - New Tools and Education Focus with Rich Benninghoff - Short #138 Feb 22, 2022

In this short podcast from AHR 2022, Leilani Orr and Eric Kaiser talk with the president and CEO of Malco Tools, Rich Benninghoff. Rich discusses some of the exciting new tools that Malco is bringing to the market and some plans for the future, especially when it comes to education.

Malco has developed the Eagle-Grip, which is a set of locking-handle pliers made in the USA with American steel. The tool is currently in a soft launch; it is currently receiving a lot of interest, so Malco has been building up inventory, forming partnerships across industries, and collecting market feedback.

One of Malco’s most exciting products is the C-RHEX line of cleanable, reversible magnetic hex drivers. These hex drivers come in many sizes and are easy to clean; the cleanable and magnetic features are especially important, as the buildup of metal resin and clippings can decrease tool longevity and effectiveness without proper cleaning.

Malco has also been focusing on trade schools and education through “Look Good, Feel Good, Do Good.” The initiative gives back to the community and provides career and education-enhancing opportunities to young people who are serious about the trade.

Over the next decade, expect to see Malco continue investing in product innovation. Rich is excited to grow the brand and help the HVAC, automotive, and other industries along the way.

Rich also covers:

Malco’s history with sheet metal fabrication
Relying on customers for feedback and ideas
“Head of the Class” program
Providing tools for shop classes in local school districts

Learn more about Malco Tools at https://www.malcoproducts.com/.

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HFC Phasedown W/ Jason O and Nathan O LIVE from AHR Feb 20, 2022

Jason Obrzut joins Nathan Orr with the HVAC School podcast live from AHR. In this episode, they discuss A2L refrigerants and upcoming regulations. They explain what a “flammable” refrigerant really is and why the industry may be making a bigger deal of the new regulations than is really necessary.

Whenever regulations are passed, we need to understand that there is a notable transition period. This period will mostly be about training, and the only people who should be working on the new equipment should be the most experienced technicians.

A2L refrigerants are mildly flammable, non-toxic refrigerants, including R-32. Flame propagation is possible but quite rare for A2L refrigerants under normal operating conditions. However, even A1 refrigerants can propagate flame under the right conditions (just not ones we’d normally see). Many countries all over the world have been using A2L refrigerants for much longer than we have, so we can make those refrigerants work safely.

All trades will evolve, and we need to be prepared and trained to adapt to changes over time. When we learn all the new practices that come with these new regulations, we become better technicians. The only place where we can make a difference is in our work, so it pays to focus on learning new things instead of resisting change.

Jason and Nathan also discuss:

A2L vs. A1 vs. A2 vs. A3 refrigerants
What does “flammable” really mean?
Recordkeeping regulations for A2L refrigerants
Getting over the fear of the unknown
Why the HFC phasedown is NOT driven by refrigerant manufacturer profits

Learn more about ESCO’s HVAC Excellence conference HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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HVAC Training Past, Present & Future w/ David Holt Feb 17, 2022

David Holt with NCI returns to the podcast to discuss the evolution of HVAC training; we cover the past, present, and the possible future of training in the industry.

In the past, we had a lot of hands-on training, whether it was one-on-one or in a traditional classroom setting. These learning practices remain beneficial today, especially since many uninformed practices are still prevalent in the industry today (charging to beer-can cold, condemning TXVs without a second thought, etc.).

However, the pandemic has forced us to consider online and remote training in the present. The content has also changed from the past; we are a lot more aware of combustion and airflow nowadays, which are very important topics for safety and efficiency. Those training topics allow us to understand what we’re doing when we take the “vital signs” of the equipment.

Being better versed in basic and advanced diagnostics will also give us a more holistic understanding of the HVAC equipment as a system, which can help us truly optimize the systems instead of changing parts and making band-aid fixes.

Moving forward, we can expect HVAC training to use virtual reality to help bring traditional hands-on training to the online sphere. We can’t expect a perfect replacement, but we can expect improvements in technology to close the learning gaps that result from online training.

David and Bryan also discuss:

NCI training during the pandemic
Components vs. systems
ASHRAE Standard 221-2020
Older educational resources and standards
Occupational safety
Pricing
Online classes, podcasts, and other modern training media

Learn more about the National Comfort Institute (NCI)’s training and sign up HERE.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Proper System Commissioning w/ Jim Bergmann from AHR Live Feb 16, 2022

Jim Bergmann returns to the HVAC School podcast live from AHR 2022 to discuss a bit about proper system commissioning. He explains the commissioning mindset and some helpful procedures.

Successful system commissioning starts with the mindset. A good commissioning organization broadens its vision; instead of focusing on the appliance, techs and installers focus on the system. Commissioning early on saves time later; you can focus on installs and maintenance instead of callbacks, and your organization can make more money as a result.

When installing and testing new piping, make sure you insulate the tubing properly and keep the lines CLOSED OFF to the atmosphere. Measuring the line set is also critical for weighing the charge properly, as long lines have special considerations.

When doing the decay test, use a quality vacuum rig and try to keep the micron gauge as far away from the pump as possible. Cleaning line sets also helps your vacuum results by getting rid of oil and moisture within the lines.

Flowing nitrogen while brazing and sweeping with nitrogen are two other important installation/commissioning practices. They may seem idealistic, but it’s easy to adopt these practices widely and reduce problematic scale buildup.

Methods for setting airflow have changed over time. Nowadays, the best practice is to take a volumetric flow measurement (such as with a TrueFlow grid).

Jim and Bryan also discuss:

Preventing callbacks and warranty returns
Evacuation and dehydration
Factory practices
One-hose evacuation with large hoses
Flushing the line sets with pigs
Nitrogen flow regulators
“Airflow before charging” and metering devices
Special considerations for MicroChannel coils

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

3D Load & Energy Calcs w/ Duct Design Feb 15, 2022

Russ King joins us for a short podcast episode about using 3D load and energy calculations with duct design. Russ has developed the Kwik Model 3D software program with the help of his son, Connor.

Kwik Model 3D uses a video game platform to build a house out of boxes instead of a sketch. The software has evolved and been integrated into EnergyGauge to do load and energy calculations based on a house’s geometry. Kwik Model makes it easy and fun to create that geometry profile for a home, which makes building design and load calculation attractive to technicians. Software like Kwik Model may especially become popular as Generation Z steps into the workforce; we can expect the learning curve to be quite shallow for the digital generation.

The Manual J calculation uses the home’s characteristics in Kwik Model and does all of the mathematical calculations in EnergyGauge for an advanced load calculation. KwikModel then receives those calculations for each room. Then, you can draw the ductwork and use an auto-size function to get the proper duct size based on the calculations.

Energy simulations use several load calculations with advanced data to figure out what the energy usage will look like in a home with a certain set of load conditions.

Russ and Bryan also discuss:

Modeling quickly with Field Draw
How building materials impact load calculations and energy simulations
Energy simulations vs. load calculations
Upcoming events with Russ King
Kwik Model’s tech support
Using the Unity platform to develop software for many different industries

Learn more about the software and get your 30-day free trial at kwikmodel.com.

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

A History in HVAC Chemical Chemistry w/ John & Mike Pastorello Feb 13, 2022

In this live podcast from AHR Expo 2022, John and Mike Pastorello of Refrigeration Technologies give us a history lesson in HVAC chemical chemistry. They also explain what it takes to make a truly beneficial product for the industry.

From the beginning, Refrigeration Technologies has focused on solving problems instead of jumping on product trends. Before Big Blu was introduced, technicians had to rely on less-than-reliable electronic leak detectors and poor-quality soap bubbles. So, John Pastorello learned about the fundamentals of foaming and bubbles to create a leak reactant that works, even creating microbubbles for tiny leaks.

Nylog has a similar origin story, and it has evolved to work for both mineral oil (red) and POE (blue) systems. As with Big Blu, John ran several tests to make sure the Nylog was compatible with HVAC equipment and did not cause contamination.

The Viper Pan & Drain Treatment was developed to replace pan tabs, which failed to remove the dead biological material in drains. The spray coats the whole pan and dissolves sludge with enzymes.

The Venom Packs are highly concentrated cleaners that arose from a move to consolidate the chemical line into something lighter, smaller, and faster. (Think about laundry detergent pods.) So, Venom Packs were inspired by laundry detergent and developed into a concentrated product line with recommended dilution ratios.

Mike, John, Jessica, and Bryan also discuss:

All the considerations that go into creating a leak reactant
“Controversial” uses for Nylog
Nylog white pipe dope for gas, water, air, and glycol
Overcoming drain/pan odors
Enzyme-based cleaning
Safety considerations with HVAC chemicals
Durability of Venom Pack packaging
Family businesses
Women in the business

Learn more about Refrigeration Technologies at refrigtech.com.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Upgrades and Proposals That Lead to Clarity & Profit w/ Michael Housh Feb 10, 2022

Michael Housh returns to the podcast to discuss upgrades and proposals that are worth considering. These upgrades and proposals can actually benefit the customer AND lead to clarity and profit without turning you into a white-shirt tech.

When assessing a system for replacement, it’s a good idea to look at the airflow side by measuring static pressure AND using a flow grid; these practices set you apart from others and supply you with good data about system sizing. Filtration is another area where you can consider upgrades and proposals; customers generally want to keep their air clean and may be happy to pay for better filtration, fresh air, and de/humidification.

Surge protection is a high-value upgrade that many customers may benefit from, especially if the electrical company allows overvoltage or the customer has a voltage-sensitive ECM or inverter system. Some upgrades are useful and can be offered automatically (the customer can decline it); depending on the climate, a humidifier or dehumidifier may fit into that category.

Proposals are a chance to put all of the offers on the table and allow the customer to select and decline whatever they want. When we adopt this business method, we would be wise to remove our egos from the process.

Some processes that add clarity to proposals include creating checklists and taking lots of pictures for the customer. You’ll also create trust between you and the customer when you establish that clarity.

Michael and Bryan also discuss:

HVAC industry game-changers
Profit margins
Free quoting
Fresh air considerations
Consistent overvoltage
Metal oxide varistors (MOVs) and the ICM493
IAQ monitors
Attic infiltration and can lights
Proposal verbiage and templates
Callbacks and consultations

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Free Tech Support w/ Clifton Beck Feb 08, 2022

In this short podcast episode, Clifton Beck joins us to talk about Bluon’s free tech support and resources available to technicians and installers.

Clifton has been very in touch with the HVAC technician community since he got his start in the trades, and he has taken that into tech support. He has noticed that the inefficiency in our industry tends to come from poorly learned practices, and working in tech support is a way for him to do his part to spread better practices while helping others.

Lately, Bluon has become more of a tech support business. The new shift to focus on innovation has prompted Bluon to shift from making equipment more efficient to making technicians more efficient. The whole HVAC industry relies on that progression from developing on equipment to people.

Tech support consists of answering calls but also creating training videos and creating layers of technician education and development. Manuals are just part of the picture; tech support helps with part identification AND the sequence of operations. Tech support reduces the amount of time it takes to learn about a part or locate components, which makes technicians more efficient and strengthens our industry.

Overall, tech support calls are opportunities to train technicians to do better; they don’t just have to give away simple answers that don’t really help anyone.

Clifton and Bryan also discuss:

Bluon’s growth
Trends in tech support calls
Tech support and community involvement
Feeling accomplished as a tech support representative

Learn more about Bluon’s free tech support on the Bluon app, or you can check out bluon.com.

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Blower Doors Don't Need to Be So Confusing w/ Genry Garcia Feb 03, 2022

Genry Garcia returns to the podcast to talk about blower doors and why ACH50 may needlessly complicate efforts to tighten a building envelope.

A large element of indoor comfort comes down to controlling the load, especially the latent load. Even though we can control indoor humidity sources, we may also deal with infiltration, which contributes to a high latent load and decreases comfort. The blower door test comes in when we can no longer control the load and need to determine how much infiltration is happening.

When using blower doors, we would typically use an ACH50 test, which takes the CFM50 (cubic feet per minute that the blower door moves to get the house up or down to 50 Pascals) and translates it to air changes per hour at 50 Pa. To do that, you would need to find the volume of the space, which adds hurdles that the HVAC technician needs to deal with.

However, Genry prefers using the CFM50 and factoring in the square footage and LAIR (leakage area infiltration ratio) to determine how tight a house is; he doesn’t focus on the building’s volume. To decrease the leakage, it’s best to stay focused on the CFM50 the entire time; worrying about the ACH50 just adds an extra step that we don’t necessarily use.

Genry and Bryan also discuss:

Connecting design and execution
Attic encapsulation
How to use LAIR
Ceiling height and stack effect
Blower door testing for code compliance vs. comfort consultation/diagnostics
Common duct problems in new constructions
Balancing supply ducts
Automation of communicating controls
IAQ products and dehumidification

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Introduction to Psychrometrics w/ Eugene Silberstein Feb 01, 2022

Eugene Silberstein, a co-author of Refrigeration and Air Conditioning Technology (RACT manual), joins the podcast to give us an introduction to psychrometrics. Psychrometrics focuses on the properties of air and its contents, especially as they relate to human comfort.

To understand psychrometrics, we need to be able to quantify air: its weight, humidity, pressure, etc. We can do a better job as technicians if we figure out the air’s content and see how it relates to the CFM and overall unit performance. That way, we can have a more holistic view of HVAC performance instead of just focusing on adding or recovering refrigerant to improve performance.

The psychrometrics chart helps us understand the conditions of the air based on quantities like water vapor, dew point, and more. The chart may intimidate techs, but it contains a wealth of information that can help technicians understand the air and the customer’s comfort better.

Basic psychrometrics can also help us grasp why furnaces don’t actually dry out air; they pull the moisture out of the air and pull it back in, so the absolute humidity stays close to the same. However, we commonly add humidifiers because the relative humidity drops with the temperature rise.

Eugene and Bryan also discuss:

How air filters and blower motors interact with the air
Things that affect the weight of air per cubic foot
Humidifying air and its effect on the density of air
High-pressure air moving to an area of lower pressure
How latent heat works
Pressure and the atmosphere
Absolute vs. relative humidity

Learn about ESCO’s e-learning network at hvacr.elearn.network/ and Psychrometrics Without Tears HERE. ESCO also holds the HVAC Excellence Conference; learn more about that HERE.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Prepare For Refrigerant Changes w/ Brandon Marshall Jan 27, 2022

Brandon Marshall, Chemours’s North American marketing manager for thermal and specialized solutions, joins the podcast to discuss refrigerant changes that are coming and how we can prepare for those. Brandon started in the industry by going to a technical school when he was 14 and has been hard at work ever since, studying light commercial design and going to college in between.

Local and global regulations have changed a lot over the years and continue to change as we continue maximizing our equipment’s efficiency. California will soon start switching to low-GWP refrigerant on new equipment in 2025; even R-410A can’t be used in new equipment. We will begin seeing the rise of A2L refrigerants and moving away from the A1 refrigerants that are more detrimental to the environment; we’ll have to focus on safety as we begin working with more flammable refrigerants.

As new refrigerants get off the ground, we can expect increased communication between manufacturers and dealers to prepare for the sale of equipment built for the new refrigerants. Although we can’t confirm anything, Brandon has speculated that the EPA will soon follow in California’s regulatory footsteps when it comes to new equipment and R-410A.

It’s a good idea to stay educated, subscribe to A2L newsletters, and follow HVAC trends in Europe to predict what might come next in North America.

Brandon and Bryan also discuss:

Educational resources about refrigerants
What “mildly flammable” actually means
European HVAC equipment
Chemours at the AHR Expo

Learn more about Chemours A2L training at opteon.com or Opteon’s YouTube channel. Check out what Chemours has in store at the AHR Expo at https://www.opteon.com/en/ahrexpo.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

The History and Future of Refrigerants w/ Chuck Allgood Jan 25, 2022

Chuck Allgood with Chemours joins the podcast to cover the history of refrigerants and discuss what the future might hold.

In the late 1800s, before Freon, the only refrigerants that were used were industrial chemicals like ammonia, CO2, and sulfur dioxide. DuPont stepped in to provide a better refrigerant for industrial refrigeration (which then spurred the rise of domestic refrigeration), so they created a non-toxic, non-flammable chemical called Freon-12 (CFC R-12) in 1928.

However, in the 1970s-1980s, it was discovered that R-12 and other CFCs depleted the ozone layer due to the chlorine content. R-12 production was banned in the 1990s per the Montreal Protocol. HCFCs like R-22 also have chlorine but in smaller concentrations; those phaseouts have been much more recent. Following news of the HCFC phaseout, HFCs and refrigerant blends became more popular because their ozone depletion potentials were 0.

Although HFCs don’t deplete the ozone layer, some of them have high global warming potential (GWP). Regulations stemming from the Kigali Amendment, such as the American Innovation and Manufacturing (AIM) Act, have been introduced to phase down the production of HFCs to slow global warming due to refrigerants.

HFOs have recently been developed to replace HFCs; these have olefins, which are double-carbon bonds with short atmospheric lifespans. So, they don’t contribute to global warming as significantly as HFCs and have GWPs of less than 1.

Chuck and Bryan also discuss:

What Willis Carrier really invented
Chlorine and ozone depletion
Development of refrigerant blends
Freon vs. Opteon branding
Refrigerants and the greenhouse effect
Oil lubricants
Best practices for mildly flammable refrigerants
Timeline of Opteon line refrigerant releases

Learn more about Chemours A2L training at opteon.com or Opteon’s YouTube channel. Check out what Chemours has in store at the AHR Expo at https://www.opteon.com/en/ahrexpo.

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Overcoming Conflict at Work w/ Andy Holt Jan 20, 2022

Andy Holt joins the podcast to discuss the ever-relevant topic of overcoming conflict at work.

Some people end up in conflicts often, so Andy recommends paying attention to how others react to the conflict you have perceived; if you are much more stressed than everyone else, then you need to look internally, not externally. The first step to overcoming conflict is to slow down and think about your reactions to perceived conflicts.

Partaking in bickering and gossip with coworkers creates a negative environment for the entire team; the best way to avoid or resolve conflicts is to handle them directly and sincerely ask the other party to start over. Overall, it’s best to take the high road and take initiative to make things right.

When dealing with conflict with bosses, it’s best to separate emotion from the facts and keep discussions simply factual. It’s good to be open, honest, and understand that you can’t control your boss’s response. As a boss dealing with employee conflict, it’s a good idea to avoid firing on the spot and give employees a chance to think about the conflict at hand, such as by giving them a paid “cool-off period.”

Customer conflicts may arise from pricing issues. The technician can ease tensions by quoting jobs up front and bundling services to show the customer where the value is. To resolve conflicts with customers, the best thing to do is be attentive to their concerns.

Andy and Bryan also discuss:

“Designing” a reaction
Dealing with big egos
Letting people go
Working towards agreements vs. forcing bargains
Dealing with hot tempers
Taking ownership of comfort problems
MeasureQuick and fact-based conversations

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Commercial HVAC Estimating Dec 30, 2021

Matthew and Nick Wavra join the podcast to discuss everything that goes into job estimation in commercial HVAC. Nick has a lot of fieldwork and project management experience, and Matthew has marketing, software, and sales experience, which helps bring in and retain clients.

Commercial estimation begins when a mechanical contractor asks for a bid on a job. The estimators go through the spec books, bidding documents, and any addendums to come up with takeoffs and a price. The estimator seeks approval from manufacturers to build the materials, and they use software to come up with an estimate. The pricing updates weekly to stay current and accurate in an economy that’s currently facing inflation.

Estimators develop takeoffs for materials and labor; each material has some sort of labor attached to it, though the labor estimates may need to be adjusted as conditions change.

Commercial contractors may make mistakes when they miss equipment or elevation considerations (when estimating labor). On-screen takeoff options significantly reduce the risk of creating mistakes, so it may be unwise for contractors to do takeoffs by hand instead of using software to help.

Matthew, Nick, and Bryan also discuss:

Sheet metal price increases
Software vs. man-made takeoffs
DX piping vs. chilled water boilers
Estimation in HVAC vs. refrigeration
CRM (customer relationship management)
Developing a commercial HVAC estimation training course
Finding a niche in the HVAC estimation business

Look for Nick and Matthew at the AHR Expo 2022 in Las Vegas! They will be at booth N9142 in North Hall.

Learn more about Matthew and Nick’s business by visiting hvacestimation.com/ or by calling Nick directly at (238)-900-6330.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Furnace Sequence of Operation - Short 137 Dec 28, 2021

In this short podcast episode, Bryan goes over the basic gas furnace sequence of operations. There are a few variations, but the sequence of operations tends to stay consistent across most furnace types.

First, a W call from the thermostat calls for heat. The circuit board will then assess the safeties to see if it can bring on the heat without causing flame rollout or other dangerous conditions. If the safety switches are all closed, then the furnace can bring on the heat. However, in some cases, the induced draft motor may come on first in some 80% furnaces. There needs to be a small negative pressure in the induced draft motor housing. To confirm that we have that pressure, a pressure switch will close under the right conditions.

Then, ignition begins. In most cases, we use intermittent-spark ignition (ISI) or hot-surface ignition (HSI). It takes some time for these methods to light the pilot, which then lights the main burner. After that, the gas valve opens to fuel the burner. On an ISI system, that’s about it until the blower comes on. However, once the main burner opens on an HSI system, a flame sensing rod can verify if you have a flame on that burner. There is a blower delay that prevents the blower from coming on and blowing a bunch of air that hasn’t yet been heated.

After that, the blower delay ends, and the blower comes on. Then, the furnace shuts off when the W call ends. Then the blower continues running for a little bit before turning off.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Starting an Internal Training Program w/ Trevor Dec 23, 2021

Trevor Matthews, the founder of Refrigeration Mentor, returns to the podcast to talk about starting up an internal training program for an HVAC/R company.

In some cases, the best lead technicians don’t want to be head trainers if the responsibility is forced upon them. However, when there is a solid training plan in place, those senior technicians might actually find the task enjoyable.

The first step to starting a training program is to ask the apprentices and technicians where their skills are at and how they want to develop their skills. That way, you can map out a program that works for the technician and figure out how to make time for thorough training.

When you grow people within your company, you’ll likely see more success than when you outsource training. It takes longer to develop the relevant skills in outsourced people; so, when you develop a solid internal training program, you can sustain it with the people who pioneered it.

We also need to focus on evaluation in training. When we assess our techs’ skills, we add accountability to our training programs. However, it takes time for techs to grow from a training program, and we need to make sure we’re rewarding progress.

Training also works best as a team approach. When we look at the techs’ strengths, we can diversify the training program and make sure that several skill bases are covered.

Trevor and Bryan also discuss:

Common excuses to avoid training
Motivated trainers and technicians
Labor shortage and skills gap
Visual, auditory, and kinesthetic learning preferences
Prevention-based training
Managerial involvement in training

Learn more about Refrigeration Mentor at https://refrigerationmentor.com/.

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Flame "sensing" - Short 136 Dec 21, 2021

In this short podcast, Bryan explains the basics of flame sensing, also known as flame rectification.

Flame sensing/rectification is a form of proving flame. When you can’t prove flame, your furnace might be dumping unspent gas into the heat exchanger, which can cause an explosion.

Flame sensing rods are common in hot-surface (HSI) and intermittent-spark (ISI) ignition. These rods stick out into the flame and connect to the furnace board. The flame creates a path between the rod and ground, which allows a very small current to flow to the board. Without a flame, there is voltage but no path, so the board can’t sense a current and will shut the gas valve off to try again.

Sensing rods can fail when they short out due to a cracked insulator, are physically broken, aren’t placed in the flame, or get covered in silica or carbon. If the furnace or burner assembly isn’t properly grounded, then the flame sensor also won’t work.

Flame sensing rods are often confused with thermopiles or thermocouples; the latter devices generate voltage and have a coating that can rub off with improper cleaning. Flame sensing rods don’t have either of these features, so you can clean these by any means necessary (without breaking them or creating grooves or pits).

To test a flame sensing rod, begin by making sure the furnace is properly grounded. Then, make sure the rod is in the right spot and that the burner assembly is in good order. Get a microamp meter (with a resolution that reads tenths of microamps). Then, connect your leads in series with the flame rod.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Grow a Business Through Customer Experience - Throwback Bonus Dec 16, 2021

This podcast episode is a throwback to one of Bryan’s first small business podcasts. In this old episode, Australian electrician and businessman Joshua Nicholls explains how he built a business by focusing on customer experience and branding. Bryan grew Kalos similarly, so they talk about the journey of going from “man-in-a-van” businesses to larger businesses with several employees.

Joshua wanted to bring old-school manners and integrity to the business world, and that’s how he branded his business. The focus on customer service over marketing earned the customers’ respect, and customers were happy to remain loyal to the business and recommend it to friends. The repeat business and referrals allow you to maintain a client base AND grow it without spending too much money on advertising.

Eventually, the business grew big enough to require Joshua to change some of his internal processes. He needed to understand when to bring external help into the business, whether those helpers were financial advisors or mentors.

Joshua reached a point where he got bored with his business, so he went to a conference in New Zealand and decided to start franchising the business. The business worked without him, and he decided to give a chance for young entrepreneurs to share in his business’s success and spread his business all over the country.

Joshua and Bryan also discuss:

Joshua’s origin story
Authenticity in business
What to do after the growth boom
Profitability vs. work-life balance
Turning customers into raving fans
Scheduling appointments in a service business
Knowing your numbers in business finance
The “One Van, One Child” initiative

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Refrigeration Defrost Termination & Fail Safe - Short 135 Dec 14, 2021

In this short podcast episode, Bryan covers the differences between defrost termination and failsafe. He also covers the basics of defrost in refrigeration applications.

In medium-temp applications (also called coolers), the box stays above freezing temperatures, but the coil may drop below freezing. When the air is above freezing, we can use off-cycle defrost. The coil defrosts when the system naturally cycles off. We may also use timed defrost, which pumps down or cycles the compressor off at set times to force a defrost cycle.

In low-temperature applications, the box will typically be below freezing. We may use electric heat to melt ice off the evaporator coil, and the fan stays off; this method is usually accompanied by a pump-down to remove refrigerant from the coil. We may also use hot gas defrost, which pumps discharge gas through the coil to melt the ice off it. (Kool gas may use a warm fluid instead of hot gas.)

We want to stop the defrost as soon as the coil is ice-free; we don’t want to keep adding heat when we don’t need to melt anything. A defrost thermostat detects when the coil is free of ice and terminates the defrost when the temperature reaches around 55 degrees Fahrenheit; this is called defrost termination. We rely on a failsafe to terminate the defrost in case the defrost termination fails; the failsafe is the maximum amount of time a system is allowed to remain in defrost.

Demand defrost uses time and temperature to tell the controls when to put the system into defrost; this method uses trend analysis and sensors to force the system into defrost at set times and intervals.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Intro to Project Management - Throwback Bonus Dec 09, 2021

This podcast episode is a throwback to one of Bryan’s first podcasts about small businesses. Cesar Abeid, former VP of construction camera company Remontech, joined this podcast to discuss the basics of project management and a book that can help you step into that side of the business.

Project management is a framework or set of tools to turn an idea into reality. Projects have a beginning and end to create something new, and project management is how we get from the beginning to the end while factoring in schedules and a budget. In essence, project management is a system.

Effective project management requires a business to create processes and procedures for its services. For example, Remontech needs to plan the actual camera installation, but the company also has a bunch of internal processes to set up servers for recording. The key to project management is to remember what must be done and assign tasks to people as needed.

One of the issues Cesar saw with project management books was the dryness and corporate nature of their language. As a project manager, Cesar used stories from his life to make his book more relatable and accessible to small business owners.

Cesar and Bryan also discuss:

Contractor-client communication
External vs. internal processes
Cesar’s book: Project Management for You
Cesar’s preferred leisure activities
Wasting time or learning?

Purchase Cesar’s book or learn more at https://pmforthemasses.com/product/project-management-for-you-bundle-1/.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Dealing with Imposter Syndrome - Short 134 Dec 07, 2021

Bryan discusses impostor syndrome, what it is, and how it may actually be useful for us.

When we feel that we’re frauds and that others wouldn’t like to be led by us if they knew how much we don’t know, we’re experiencing impostor syndrome. Contrary to what others might believe, impostor syndrome isn’t all that bad and may even be necessary for a healthy self-image.

On the other side, we have the Dunning-Kruger effect, which is when people are confident in the things they have very little actual knowledge of. They think they’re experts and close themselves off to other sources of knowledge. On the other side of the Dunning-Kruger effect spectrum, true experts are acutely aware of what they still don’t know. We would be wise to know what the edges of our knowledge are and give others a chance to share their expertise when we reach those limits.

When people learn more about a subject, they become much more aware of what they don’t know. Wisdom comes from knowing what you don’t know. However, if you feel that feeling of inferiority, you can still share the knowledge you have while seeking feedback and deferring to others who know more than you. (That’s especially true of Bryan, who has a summary knowledge of industrial refrigeration and defers to others who know more about it.)

In the end, we’re seeking authenticity and self-awareness. Rather than avoiding impostor syndrome, we can embrace it and understand how it can lead to self-awareness, wisdom, and especially self-improvement. “Fake it till you make it” can only help you up to a certain point.

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Transforming Grocery and Cold Storage with Data Dec 02, 2021

Amrit Robbins of Axiom comes on the podcast to discuss how we can use data science to transform grocery and cold storage.

Axiom Cloud uses cloud analytics and AI to map data and analyze trends on refrigeration racks. It can be particularly useful to keep track of readings all the time because it’s impractical to rely on a human to take and record readings 24/7.

Grocery stores are unique because they have so much product at stake and are relatively inflexible in their usage of energy. If something goes wrong on a rack, thousands of dollars worth of products may be lost.

If we could collect and review data at our fingertips, we could spot potential problems before the store loses money. These systems may also have alarms for case temperature problems, floodback conditions, and even some less immediate issues, such as a lack of floating suction.

Axiom Cloud also monitors when systems go into defrost, so you can assess the cycles of case groups and figure out if they correspond to any issues.

When you have data collection, you’re not relying on a “virtual technician” to automate HVAC work. Instead, data science can empower HVAC technicians and help them do their jobs more efficiently so that they can respond to issues before they become emergencies and serve customers better. After all, computer-based systems can’t repair or clean units!

Amrit and Bryan also discuss:

Generating value on behalf of the customer
Compressor failures
Technician labor shortage
Creating sustainable working hours
Developing more flexible energy usage
Monitoring temperature rise across cases
Thermal banking
Preparing for data analytics to come to the industry

Learn more at axiomcloud.ai.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Superheat Talk - Short 133 Nov 23, 2021

In this short podcast, Bryan goes over the basics of superheat and explains why it matters to us.

Superheat is the temperature increase above a substance’s saturation temperature or boiling point. When a substance is superheated, that means it is 100% vapor; there is no liquid at all. We can look at our superheat to determine how much refrigerant is feeding our evaporator coil.

A lower superheat indicates that our evaporator is more full of refrigerant than a high superheat, meaning that the refrigerant is feeding the evaporator coil well. Generally, a lower superheat value will be more efficient, but if the superheat gets too low, we can get liquid in the suction line and compressor.

An evaporator can maintain roughly the same temperature throughout the bulk of the coil because the temperature stays the same during a phase change. As the refrigerant boils off from its liquid state, it remains at the boiling point. You generally want to see no less than 6 degrees of superheat, especially at the compressor. Zero superheat indicates that you have some liquid refrigerant (or that the system is off).

Superheat can get tricky when we use refrigerant blends with glide. The different refrigerants in a blend have different boiling points, so the evaporator temperature can drift up. When determining the superheat of blends, we use the dew point to calculate the superheat (and bubble point for subcooling).

We get superheat in the evaporator (suction line at the evaporator outlet) and the compressor (suction line at the compressor inlet). The latter will be higher because some sensible heat will be absorbed in the suction line.

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Liquid Quality vs. Subcooling Nov 18, 2021

In this podcast episode, Bryan and Eric Mele talk about sight glasses, the significance of subcooling in refrigeration, and liquid quality.

While we measure subcooling quite often in HVAC work, we rely on sight glasses and liquid line receivers far more often in refrigeration. You need a sight glass to determine the liquid quality in a refrigeration system. Subcooling is one way to assure liquid quality without a sight glass or a receiver.

Subcooling refers to the temperature drop below liquid saturation. Head pressure can dictate subcooling, and several other factors can dictate the condensing temperature, including stacking. We use sight glasses because a clear sight glass can tell us that we have a full column of liquid (therefore subcooling) without hooking up gauges.

In HVAC, we care about having a certain level of subcooling because we want to make sure the refrigerant is fully liquid when it reaches the metering device; no bubbles should be present by the time it reaches the metering device. Like the suction line, the liquid line is a place where heat can be absorbed into the refrigerant. So, some manufacturers recommend insulating the liquid line to prevent heat from transferring to the refrigerant in the liquid line.

Unit orientation also affects subcooling. For example, you can shorten the liquid line sizing if your liquid line goes downhill to the air handler. Conversely, longer lines and uphill liquid lines require special considerations when it comes to subcooling.

Eric and Bryan also discuss:

Liquid line receiver fill standards
Subcooling and efficiency
Sight glass placement
Stacking liquid in the condenser
Pump down strategies
Mechanical subcooling
Flash gas
“Free” subcooling
Ambient temperatures

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Aluminum Repair Tips - Short 132 Nov 16, 2021

In this short podcast, Bryan explains the basics of repairing aluminum, such as on coils or tubing.

Repairing aluminum can save lots of time on mission-critical calls and can help stop refrigerant leaks that lead to ozone layer depletion or global warming. Soldering makes almost all of the aluminum repair work we will do. (Brazing is possible, as aluminum has a melting point of 1200 degrees, but that’s still a bit too close to the brazing threshold.)

When working with aluminum, we need to recognize that it melts at a lower temperature than brass, steel, and copper, and it doesn’t change color. Aluminum is also thinner and almost fades away under excess heat.

First, you’ll want to figure out how to get the base temperature to the right temperature, usually with a flux. (Some fluxes require cleaning, some don’t; either way, we recommend cleaning.) The powder flux should go clear, and then you’ll be ready to apply the rod. In many cases, indirect heating can be difficult if not impossible.

After you choose your alloy, you need to choose your torch. We recommend using a swirl-tip air-acetylene torch. (It’s good to use a 3 tip for microchannel.) When working with an air-acetylene torch, you will run lower temperatures than oxyacetylene torches, but you will experience more convective heat. (Heat control is the key!)

When doing a repair, you want products that will make a solid bond to the outside of the joint. Make sure your products are for repairs, not for joining aluminum tubing.

If you do aluminum repairs on an evaporator or condenser coil, cut the fins out of the way. Make sure your work area is exposed and clean.

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Specifically About Heat - Short 131 Nov 09, 2021

In this short podcast, Bryan goes over energy transfer and heat, specifically specific heat.

BTUs per ton is a common measurement; a BTU (British thermal unit) is the amount of heat it takes to raise the temperature of one pound of water by one degree Fahrenheit. 12,000 BTUs per hour is equal to one ton in heating or cooling technology. It takes one “ton” of heat to melt a ton of ice, but we kept the measurement and terminology as we moved away from using ice in industrial refrigeration.

When it comes to specific heat, we have to remember that one BTU has a different heating or cooling impact on different substances. Most fluids have a specific heat lower than water, meaning that one BTU of heat will result in more heat transfer in that substance than water. Air is one such fluid that has a lower specific heat than water (0.24 vs. 1); it’s easier to heat air than water. However, the specific heat of vapors can change with temperature and pressure.

When we change a refrigerant from a liquid to a vapor in the evaporator coil, it will reach saturation before boiling. As the refrigerant boils, the temperature will stay the same because the absorbed heat will all contribute to the phase change as latent heat. Even though most refrigerants have low specific heat, direct expansion systems can still move a lot of heat because it takes a lot of latent heat to complete a phase change.

In other systems that don’t use direct expansion (using glycol or water instead), specific heat is more integral to the effectiveness of heat transfer because latent heat isn’t a factor in heat capacity.

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Pressure Measurement Pro Tips w/ Steve Rogers Nov 04, 2021

In this podcast, Steve Rogers from The Energy Conservatory explains some pro tips for pressure measurement.

There are three common types of pressure measurements: absolute, gauge, and differential. Absolute pressure is the pressure in a particular space in reference to a complete vacuum. (All absolute measurements use the zero point as a reference.) Gauge pressure uses atmospheric pressure as a reference point (which varies with altitude and location). Differential pressure relies on two connections (one of them is a reference point to the other).

The Energy Conservatory recently designed a manometer (DG-8) that differs from the standard manometers. The purpose of that manometer is to make pressure measurements in a more cost-effective way. Most manometers have similar sensors (diaphragms move with pressure, and the measurement read is the resulting difference in resistance). However, the DG-8’s methodology can help it yield much more accurate measurements.

When dealing with small pressure measurements (like Pascals), the DG-8 is one of the most accurate manometers you will find on the market.

When you look at room pressure, keep in mind that pressurizing one room will depressurize another. Temperature differences also impact the pressure, and the HVAC unit can cause differences in pressure to arise as a result of temperature differences. When you run the kitchen or bathroom exhaust and expel a lot of air in your home, you can also bring the home under negative pressure; that can even cause your water heater to backdraft.

Steve and Bryan also discuss:

Blower door manometers vs. DG-8 manometers
Pascal scale
Room pressures and air paths
Infiltration and its effect on load calculations
Dominant duct leakage
Combustion appliance zone (CAZ) testing
Mechanical ventilation and pressure
Orphaned water heaters
DG-8 and the TrueFlow grid

Learn more about the DG-8 HERE.

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Copeland Reciprocating CS Compressors w/ Trevor Oct 28, 2021

Trevor Matthews from Refrigeration Mentor comes on the podcast to talk about Copeland reciprocating CS compressors. He and Bryan cover Bulletin AE4-1433 (found HERE) as they look at the operating envelopes for the CS compressor.

The CS compressors are hermetic reciprocating compressors that can work with some of the newer refrigerants. You will likely see these compressors in applications with smaller tonnages.

You’ll usually want to charge these compressors with liquid refrigerant. If you have more than 6 pounds of charge in the system, using an accumulator is recommended. Under those charge conditions, the system also needs a check valve between the receiver and the condenser.

Suction line pressure drop is one of the most important things to pay attention to in the system. Make sure the suction line is of an appropriate size, that filter-driers don’t have restrictions, and that accumulators aren’t clogged. Overall, many manufacturers recommend removing the duction driers to keep the pressure drop minimal.

The recommended runtime for these compressors is also very short, only 5 minutes. CS compressors should cycle no more than 12 times per hour, and the off-time between cycles should be a minimum of 10 seconds.

Before returning or replacing a compressor, make sure you check all of the electrical components, including the capacitor. If the compressor hums but has power, you could simply have a capacitor or potential relay issue.

Trevor and Bryan also discuss:

Return gas temperatures
Discharge line temperature
Compressor superheat and flooded conditions with refrigerant blends
Crankcase heaters
Pump-down recommendations to stop short cycling
Initial charge vs. recharge
Metering devices
Line sizing
Electrical shorts
Sticking relays
Single-phase vs. three-phase power
Megohm testing
Purging with and flowing nitrogen
Burnout cleanup procedures
Locking/tagging out equipment
Hard start kits, potential relays, and start capacitors

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Adiabatic Cooling - Short 130 Oct 26, 2021

In this short podcast episode, Bryan explains the science behind adiabatic cooling. Adiabatic cooling occurs in specific HVAC/R applications and in our environment as air temperatures and pressures change.

When we think of cooling, we refer to the loss of heat; we are either referring to the change in the total BTU content of the air mass or the temperature change. Adiabatic cooling takes sensible heat and transforms it into latent heat.

The most simple forms of adiabatic cooling can be seen in cooling towers and swamp coolers. In evaporative or swamp coolers, you have a pad saturated with water, and air moves over it. When air moves over the media, some of the energy helps evaporate the moisture on the pads, so the air loses sensible heat and becomes cooler. The thermal enthalpy (total heat content) stays the same, but some of the sensible heat has transferred to latent heat.

Air that goes through a swamp cooler goes in with higher temperature and lower humidity, and it leaves with a lower temperature and higher humidity. The BTU content stays the same; the energy merely transforms. As a result, we usually only use swamp coolers in arid environments where higher humidity is desirable. You also can’t compare these to compression-refrigeration systems because compression refrigeration aims to change the BTU content and is NOT adiabatic.

When we run air over an evaporator coil, some of the water vapor in the air condenses to liquid water in the drain pan. Some of the energy in the refrigerant changes the state of the water vapor to liquid water instead of changing the temperature. You’ll see a lower delta T when your return relative humidity (RH) is higher.

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Fighting Boredom at Work - Short 129 Oct 19, 2021

In this short podcast episode, Bryan shares his top tips for fighting boredom at work. You can use these tips to help you get out of a rut if you don’t feel productive or get bored easily.

The first tip for fighting boredom is to see the art or creativity in your work. Even in the HVAC industry, there are plenty of opportunities for artisan skills and craftsmanship. When you see your work as an art that you need to refine, it’s easier to get engaged in your work and feel proud of it. That's especially true of tasks like duct strapping and brazing.

Another way to stop from getting bored is to do more things that challenge you. Being constantly challenged and being out of your comfort zone keeps you interested and can even spark a new passion.

Pursuing mastery allows you to focus on one particular skill or subject to become an expert. When you master a skill, you also become a marketable job candidate and can carve out a niche within your organization. Mastery is about going deep rather than wide, and more people will feel enriched by working towards mastery than others.

If you’re a social person, finding a community can keep you from getting bored. When you have a community, you will be around people who have the same interests and experience the same challenges as you. So, you won’t get bored from feeling alone.

Mentorship is another way to rekindle your passion. When you choose to invest in and guide less experienced people in the trade, you can feel a renewed sense of purpose in your work.

And if you’re REALLY bored, you can change everything up entirely and try something new.

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Check out information on the 2022 HVACR Training Symposium at hvacrschool.com/symposium/.

Review Of Vacuum For Service Revisted Oct 14, 2021

In this podcast episode, Bryan goes through the addendum to the book Review of Vacuum for Service Engineers. He and Jim Bergmann had the honor of revising the latest edition in 2020. You can get the latest edition of Review of Vacuum for Service Engineers from TruTech Tools HERE.

Pulling a Schrader core before evacuation makes a big difference in the speed of the evacuation. You can use a core remover tool to pull the cores when the system is NOT pressurized.

There are three common types of ports to access the system: the Schrader core, high-flow core (CoreMax), and the multi-position service valve. You can mid-seat the multi-position service valve for high flow, but you need to remove or depress cores on the other two port types. (You must use a special CoreMax CRT to remove high-flow cores.)

Three factors limit the speed of evacuation: the conductance speed of the pump, of the connecting hoses, and of the system. The hoses and manifold can severely impact evacuation. TXV and piston metering devices have short orifices and have very little impact on the evacuation time; on TXVs and EXVs, the valve should be fully open.

When pulling a vacuum, make sure the vacuum pump works properly and has clean oil. Once you know that the pump is working, only pull on a tight system (no leaks) and make sure the seals are in good shape.

Bryan also discusses:

Micron gauge and hose placement
Core depressors and CRTs
Refrigerant holding charge
When core restrictions are helpful
Single-hose vs. two-hose evacuation speed
Moisture removal
One-hose evacuation of a split air conditioner
Decay testing
Hard shut-off valves
How to solve micron gauge issues
Nitrogen sweeps for wet systems

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Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Electric Heat - Short 128 Oct 12, 2021

In today’s short podcast, Bryan discusses electric heat, how we use it in our work, and what it does.

Also called heat strips or heat elements, electric heat is a supplemental heat source that we usually see on heat pumps. We generally see them in fan coils within a cartridge or a kit at the top of an air handler. However, not all systems have backup heat.

We want to avoid running electric heat as much as possible because it is inefficient. There is almost nothing we can do to make heat strips more efficient; they will usually yield around 3.41 BTUs per watt.

We usually only run heat elements when a heating system can’t keep up with the heat loss. However, the electric heat often runs more often than it should, which can cause inefficient conditions. You can avoid inefficient conditions by programming the thermostat properly.

If you reduce the voltage on the heat strips, the less heat they will produce. Current ratings also differ between 208v or 240v applications. When you have more voltage, you’ll have more current as well.

In some municipalities, you may have to use a thermostat that keeps heat strips OFF unless the temperature is below a certain value, often 40 degrees. Your electric heat should also be the last resort for a system.

Heat strips also help with heating when a heat pump is in defrost. The defrost board backfeeds the electric heat. These heat strips are also often designed with an interlock that forces the blower on whenever the electric heat is on (but not the other way around).

Bryan also discusses:

Kilowatts and electrical ratings
Wiring and relays
Wire sizing
Furnace-to-heat-pump conversions
Possible hazards

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Check out our handy calculators HERE.Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Introducing Refrigeration Mentor w/ Trevor Oct 07, 2021

Trevor Matthews comes on the podcast to discuss his newest project, Refrigeration Mentor. Refrigeration Mentor uses Trevor’s experience as a trainer and field technician to guide others in their careers.

Trevor’s goal is to help commercial refrigeration technicians grow and become more confident in their skills. He wants them to become the best technician they can be, and he believes that mentorship is one of the things that make our industry great. Mentorship can help people advance their careers, sharpen their skills, and ease their anxiety about work.

When we share knowledge, we bring value to the technicians. That value extends to the customer when technicians are more confident in their work and do better jobs. A good mentor has a commitment to doing quality work within the trade but will make their mentees feel comfortable to admit what they don’t know.

Mentors can also help their mentees develop a solid work-life balance that helps mentees be present to their jobs and their families. The mentor’s job is to help their mentees reach their goals, whether that’s learning a new skill, entering a leadership role, or even starting a business.

Trevor also wants to help business owners or managers strengthen their teams. He believes that a dynamic culture and a strong emphasis on training will help a business (and the industry as a whole) grow. His mentorship approach comes from strengthening technicians, businesses, and the industry from the heart.

Trevor and Bryan also discuss:

Holistic training
Hesitancy to admit what we don’t know
Passionate teachers
Mental health
Starting and managing a business from the inside
Investing in training and mentorship

Check out Trevor’s website at https://refrigerationmentor.com/.

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/sympos

Effective IAQ Measurement & Control w/ Haven Oct 05, 2021

In this podcast, Ben from HAVEN IAQ, Kaleb, and Bryan discuss how to control indoor air quality and take effective, meaningful, accurate measurements.

HAVEN is a platform that offers hardware and software delivered to a homeowner through an HVAC professional. HAVEN’s goal is to give its customers a healthier, more comfortable home using IAQ solutions.

The hardware (controls, etc.) works with the HAVEN software to give customers and contractors data about IAQ and the performance of the HVAC equipment. Right now, you may install up to two HAVEN controllers and one monitor per zone to help control equipment and monitor the air content.

Air sampling occurs every hour, whether the HVAC system is running or not. Customers can learn to control their ventilation habits to address acute events (e.g., a spike in humidity from cooking), which only result in short-term IAQ problems. However, contractors can use the air sampling data to develop solutions for chronic events (e.g., constant high humidity).

Solutions, even simple filtration ones, are best left to the contractors to figure out. The integration of most IAQ products requires some degree of design and planning. HAVEN products do NOT provide plug-and-play solutions. While “demand” solutions can introduce outdoor air to prevent a viral problem, you could introduce a moisture problem without proper planning.

Ben, Kaleb, and Bryan also discuss:

HAVEN central air controller
Building relationships with customers
Software integrations with other platforms
Filtration caveats
HAVEN Pro Portal and Personal Use Program
Ease of connecting HAVEN controllers to equipment
“Demand” ventilation, dehumidification, etc.
Importance of airflow
Making IAQ product sales and educating homeowners
IAQ placebos
In-duct monitoring
Introducing HAVEN products to your market

Please visit pro.haveniaq.com to access HAVEN’s Pro Portal.

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

College vs. Skilled Trades w/ Ryan Gorman Sep 30, 2021

Ryan Gorman comes on the podcast to discuss the differences between a college education and early career opportunities in the skilled trades.

Many parents feel pressured to send their children to college and encourage them to get a four-year degree. Despite what society may lead us to believe, there is no shame in thinking that college may not be suitable for you or your child; the skilled trades have many opportunities for people to learn throughout their lives and make a good living.

In many cases, parents may see college as a ticket to the starting line. Unfortunately, college tuition has skyrocketed over the years, and a good ROI is not guaranteed. Instead, a career in the skilled trades can allow a person to develop hard skills and land a well-paying job at a young age. As the skills gap widens, young people who learn skills make themselves attractive to employers and increase their earning potential.

Children and teenagers who want to become engineers may actually prefer a trades career where they get to work with their hands. The path to the trades is less expensive than getting a four-year degree and may prove more fulfilling in the long run. Internships, small businesses, and trades careers are viable paths for young people; we don’t present these possibilities at a young age, but they are worth considering for people who may not benefit from college.

Ryan and Bryan also discuss:

The arbitrary structure of college programs
Parents wanting better for their children
Overvaluing the 4-year degree
Networking
The skills gap
Craftsperson vs. technician
Feeling "stuck"
Attending college at an older age
Lifelong learning
Universal skills vs. specialization
Suggested resources for people who feel "stuck"

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Check out our handy calculators HERE.

Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

A2L Refrigerant Facts w/ Jason Obrzut Sep 23, 2021

Jason Obrzut comes on the podcast to discuss A2L refrigerant facts. Jason is a member of AHRI’s Safe Refrigerant Transition Task Force and author of the RACT manual.

ASHRAE designates refrigerants into categories based on toxicity (A or B) and flammability (traditionally 1, 2, and 3). So, the new A2L designation indicates that a refrigerant is relatively non-toxic but has a flammability value between 1 (low) and 2 (moderate). While propane (R-290) is a good refrigerant because it is natural and has low toxicity, it is very flammable (A3).

Future refrigerants will likely fall under the A2L designation; the mild flammability will probably be the tradeoff for efficient, low-toxicity refrigerant with a low environmental impact. However, A2L refrigerants cannot be vented, even despite their low GWP. We also cannot use these refrigerants in retrofits.

A2L refrigerants will likely become much more prevalent around 2023 as HFC refrigerants phase down. The phase-down period will be specified shortly, and it will begin with a 10% reduction; the specific parameters of the phase-down have yet to be set.

When working with A2L refrigerants like R-32, you can expect little to no change in how you work on equipment if you’re already employing the best practices. Sizing and capacity will hardly change in the residential market. In the commercial sphere, these systems still look and operate quite similarly to current units.

Jason and Bryan also discuss:

Refrigerant detection systems (RDS)
Flowing nitrogen and other best practices
Non-A2L HFC alternatives
Left-handed threads
Non-standard safety practices
R-32 properties
Refrigerant glide

To learn more about A2L refrigerants, check out the AHRI Safe Refrigerant Transition Task Force’s webinars, newsletters, and fact sheets CLICK HERE.

Check out information on the 2022 HVACR Training Symposium HERE.

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Dealing with Difficult People at Work Sep 16, 2021

In today’s podcast, Bryan and some Kalos employees discuss how to deal with difficult bosses and coworkers in HVAC/R work.

Whether your coworkers have anger issues, are careless, or are miserable people, you don’t want that negativity to affect your job satisfaction. Addressing the behavior may likely help, but you don’t want to attack the other person. The key to dealing with difficult coworkers is to communicate boundaries respectfully with the goal of improving the work environment. Boundaries are also important when dealing with sarcastic people or those who make inappropriate remarks.

Any work environment with lots of people is bound to have cliques and tribes. You’re best off not getting involved in any of that drama; the best thing you can do is be kind whenever you have the opportunity. Nepotism may also fall under tribal behaviors, and it may cause you to rethink your future with a company.

On the leadership side, micromanagers can be frustrating—doubly so if your boss also happens to be condescending. If you have micromanager tendencies, try setting clear objectives and give your technicians room to develop. (If you’re on the receiving end, talk to your boss about bigger-picture objectives to cut down on micromanagement.)

Learning is all part of working in the HVAC/R field, but you may encounter friction with bosses who won’t invest in learning or coworkers who refuse to learn new things. Try to have productive conversations with these people. If you’re talking to a boss who doesn’t invest in training, try to communicate your professional and educational needs. If you have a stubborn coworker or helper who doesn’t want to learn, try to help them understand the new material by using similes and metaphors.

We also discuss:

Distractions
Sarcasm and rudeness
Egomaniacs
Inappropriate exaggeration
Dishonesty
Overreaction

Check out information on the 2022 HVACR Training Symposium HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The ACCA Manuals w/ Ed Janowiak Sep 09, 2021

In today’s podcast, Ed Janowiak comes onto the podcast to talk about the Air Conditioning Contractors of America manuals. Ed started off in the field and has recently become the new Manager of Design Education at ACCA. You can follow him on Snapchat (skinnyed).

ACCA (Air Conditioning Contractors of America) is responsible for publishing and setting the standards in all of the books we use for residential and light commercial HVAC work. (Residential work typically encompasses Manuals J, S, D, and T).

The manuals can be very math-heavy. Many software programs have come on the scene to help automate the math to some degree, but the manuals will still remain relevant for years to come. The ACCA manuals offer guidelines for predictable results, and much of a technician’s success will come down to how well they understand the order of operations.

In our trade, we have developed rules of thumb that help us with sizing and load calculations. However, those won’t work all the time, and the predictability element is lost. The ACCA manuals exist so that you can complete your calculations, sizing, and equipment selections with some degree of rhyme and reason.

ACCA updates the manuals on 5-year cycles; the manuals require periodic updates to keep up with new climate trends and new equipment as it hits the market. The information in the manuals is not 100% accurate and is variable, but that is just a product of our ever-evolving industry and world.

Ed and Bryan also discuss:

Leadership responsibilities in ACCA
Why HVAC business owners should be aware of the ACCA manuals
400 CFM per ton
Mediocre designs
Moisture problems and design conditions
Basements, elevation, and insulation
Constructive criticism
ACCA training

Check out information on the 2022 HVACR Training Symposium HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Money Conversations for Techs Sep 02, 2021

In today’s podcast, Bryan and Jesse talk about how technicians can have conversations about finances and money in the HVAC business.

The first step for any successful business is to provide customers/clients with a product or service of value. However, there must be a balance between providing something of value to customers and providing excellent customer service.

When starting an HVAC business, one of the biggest mistakes is making money the top priority. Money can only become a factor after a business establishes the value of its services and communicates its value to its customers. There is no hard line for fair pricing, so the contractor and customer must have productive conversations to establish a price tag and the expectations for the work performed.

That same mistake applies to employees who want raises or promotions. Employees may feel as though they are owed more for their work, but they must establish their value before they get a raise. Again, the goal is to avoid unmet expectations.

Profitability and value are not just important to the managers and bookkeepers of an HVAC business. Technicians are the ones who bring those things to their organization. Labor is expensive, but it must be valuable if you want to turn a profit (either for the business or in the form of increased wages). Technicians can increase their value and profitability by mastering skills and learning niche practices.

When a business becomes more profitable, it can invest in better training for its techs. It can also have more control over the customers it chooses to serve.

Jesse and Bryan also discuss:

Maintenance agreements
Service repairs
Misunderstandings about tax write-offs
Bundling and flat-rate pricing
Establishing value with commercial customers
Technician skillsets
Warranty challenges
How to communicate price ranges
Treating difficult clients with respect

Check out information on the 2022 HVACR Training Symposium HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Sleeve vs. Ball Bearings - Short 127 Aug 31, 2021

In today’s short podcast, Bryan explains the differences between sleeve and ball bearings. Techs often make some avoidable mistakes because they either don’t know the difference between the two or don’t notice the bearing type on their equipment.

On a basic sensory level, ball bearings tend to be louder than sleeve bearings. So, if you replace a sleeve bearing motor with a ball bearing motor, then excess noise may not indicate any problems after all. Lubrication is usually more consistent with ball bearings; those bearings have a far smaller contact area than sleeve bearings.

Sleeve bearings don’t usually have the best longevity; they have a larger contact area and can burn out quickly, so they are more common on smaller equipment where they will experience less intense axial forces. Those sleeve bearings also aren’t as effective as ball bearings in variable-speed equipment. When techs put in a motor speed control and don’t pay attention to the bearing type, they may end up burning up the motor if it has sleeve bearings.

To determine which type of bearings your equipment should use, you can take note of a few different things. Ask yourself if there are motor speed controls or any sort of motor speed variability. When the answer is yes, you’ll be better off using ball bearings. If longevity is a concern, then ball bearings are almost always the ideal choice.

If nuisance noise and inexpensiveness are greater issues than longevity, then you’ll be better off replacing a sleeve bearing motor with another sleeve bearing motor than a ball bearing motor.

Check out information on the 2022 HVACR Training Symposium HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

You can also check out our handy calculators HERE.

Horizontal Scroll Compressors w/ Trevor Aug 26, 2021

In today’s podcast, Trevor Matthews from Emerson talks about horizontal scroll compressors. Throughout the podcast, we refer to Bulletin AE4-1338 (R3). You can find that bulletin HERE.

Horizontal scroll compressors are common in mobile applications, like buses and trains. They’re shorter in height than other compressors, so they fit into tighter spaces and are ideal for transport refrigeration.

Scroll compressors are particularly susceptible to overheating, and you need some controls to protect your compressor from damage. To prevent overheating, scroll compressors require pressure relief controls. You can typically use an OEM high-pressure control to protect the system. A low-pressure cutout installed in the suction line can help prevent TXV failure and a wide range of restrictions.

Accumulators are especially important for horizontal scrolls in heat-pump applications. However, accumulators have a fine mesh screen that can become clogged easily. So, we highly recommend replacing your accumulator in the case of burnout, not reusing it.

Refrigerant migration prevention is a little more complicated than in refrigeration systems with other compressors. You can use a crankcase heater, but you may also need a check valve in the discharge line and a liquid line solenoid valve. We don’t use pump down cycles for refrigerant migration; we use them to prevent the gas from moving backward and reversing the scroll.

When commissioning a three-phase compressor, you need to put your gauges on before starting the system up. You may also consider using a phase rotation monitor to make sure the scroll compressor is rotating in the correct direction (usually clockwise but not always).

Trevor and Bryan also discuss:

Variable-speed horizontal scrolls (ZRH vs. ZBH models)
Superheat requirements
Floodback and slugging
Starting and running
Extreme discharge line temperatures
Arcing fusite under vacuum
Functional checks
Pressure drop in the suction line
Operation envelopes
Pressure control set points

Check out Emerson for more information.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Buck & Boost Autotransformers - Short 126 Aug 24, 2021

In today’s short podcast, Bryan discusses buck-boost (auto) transformers and what they do.

Autotransformers are not automatic; the “auto” prefix comes from the fact that autotransformers only have one inductive winding. That winding is shared by the primary and the secondary, so it is not an isolation-type transformer. These transformers run current through the same winding used for induction.

Buck-boost transformers rise or decrease voltage. When the transformer “bucks,” it decreases voltage from primary to secondary, and a “boost” increases the voltage from primary to secondary. In other words, a “boost” is a step up, and a “buck” is a step down on a small scale.

You can only wire these transformers if you use the manufacturer literature. There are many types of autotransformers, and you need to know the exact setup for your transformer’s specific design. Generic diagrams will usually not suffice.

When sizing a buck-boost transformer, you must keep your start load in mind as well. As technicians, we might not be able to handle the specifics of sizing based on the start load, but it’s still something to keep in mind.

The “buck” configuration of the buck-boost transformer is especially helpful in markets where the utility company tends to produce overvoltage. Our specific setup uses the Micron J750A1EB1A02, which you can learn more about on YouTube HERE. The “boost” configuration helps when a motor doesn’t get enough voltage from the utility source.

Before you buck or boost the voltage, remember to account for both sides of the equation; if the utility changes the voltage, you still want to be within range.

Bryan also covers:

Ratings
Current and capacity changes based on voltage
Inverter-driven technology
Voltage monitors (ICM493)

You can learn more about the 2022 HVACR Training Symposium HERE.

If you have an iPhone, subscribe to our podcast HERE, and if you have an Android phone, subscribe HERE.

An Effective IAQ Process w/ John Ellis Aug 19, 2021

In today’s podcast, John Ellis joins Bryan to talk about indoor air quality (IAQ). He also explains the ideal process for providing IAQ solutions. John has a lot of experience working as a consultant for people who have respiratory issues, so he has valuable perspectives.

The HVAC and IAQ fields intersect in the areas of thermal comfort, humidity, building pressures, ventilation, filtration, and source control (which pollutants are present, where they come from, and how we can remove them).

John does not believe in throwing IAQ products at a problem. He believes in a thorough analysis of the structure to present the customer with solutions tailored to their home and needs. Ideally, John would like to see technicians take a process-oriented approach to indoor air quality: investigate, analyze, and quote. He believes in the power of slow, complete diagnosis, including listening to customers’ complaints. Remember, they’ve been living in the structure and can tell you about the issues they’ve noticed in their home and their health concerns.

When you analyze a system, you may have to do additional testing beyond a visual inspection. Sometimes, you can’t always find fungal growth or must call an expert to test for asbestos. The key to practicing IAQ is to be open-minded and seek help from experts beyond your field.

While IAQ solutions can be expensive, they can be well worth it for many customers. Try not to pass your own judgment on the prices; after all, you are performing quality work and could save your customer money on medical bills.

John also explains:

How to start training for IAQ sales
Customer questionnaires
Maintenance agreements
Becoming comfortable with IAQ diagnostics
How to present high costs and financing options to
customers
Being a truly caring, attentive consultant
IAQ marketing
Making money as an IAQ consultant

If you want to talk to John about IAQ, you can contact him at (505)-652-8119 or dynamicairconsulting@aol.com.

If you have an iPhone, subscribe to our podcast HERE, and if you have an Android phone, subscribe HERE.

You can learn more about the 2022 HVACR Training Symposium HERE.

Caring for Technician Mental Health Aug 18, 2021

In today’s podcast, Scott Krasman from TZOA, Andrew Greaves, and Kaleb Saleeby join Bryan for a conversation about mental health in the trades. We have a greater awareness of mental health than we ever did before, and although some of us may make fun of the topic, it is something we should focus on as HVAC technicians and business owners.

“Toxic” is a common buzzword these days, but it’s relevant here. A work environment with toxic traits will wear you down over time as you are exposed to disillusioned or selfish journeymen or senior techs at work who disregard your wellbeing and development. Sadly, these behaviors often come from low morale and projection.

HVAC industry leaders can take strides by promoting a culture of inclusiveness and encouraging conversations about mental health. There is also an element of personal responsibility within techs to acknowledge if something is wrong and to have honest conversations with their leaders. As techs, we need to know when to ask for help if we need it. Leaders must also look at themselves and address their own mental health issues so that they don’t project their issues onto others.

As techs, we need self-awareness and intentionality to address our mental health. We need to understand what’s going on with ourselves (even if we need to talk to mental health professionals) so that we can take steps to get the support we need.

We also cover:

Helping younger techs grow
Growth and discomfort vs. abuse and suffering
Training, communication culture, and workload
What it means to be in a dark place and how to get out of it
Opening up to others about our struggles
Active recovery
Relationship issues and addiction
Self-diagnosis and misdiagnosis
Executive functioning
Technology for mental health
Caring for your body

You can learn more about the 2022 HVACR Training Symposium HERE.

If you have an iPhone, subscribe to our podcast HERE, and if you have an Android phone, subscribe HERE.

Troubleshoot the System! w/ Jim Bergmann Aug 12, 2021

In today’s podcast, Jim Bergmann talks about troubleshooting the entire system. He takes a holistic approach to the art of troubleshooting, NOT just an equipment-centered one.

According to NIST, the most common HVAC system problems are duct leakage, refrigerant undercharge, and oversized equipment (often for undersized ducts).

Duct leakage heavily affects the envelope; the equipment only plays a part in conditioning a space. As such, you will want to seal up holes that lead to unconditioned spaces, such as behind the thermostat, to avoid creating negative pressure. When there is that negative pressure, especially close to the thermostat, the home could be at risk of over-cooling.

We check that the filter is clean, but we rarely ever question if the filter is good enough for the home. If the filter does not do a good job of improving air quality, you may consider changing the filter type or reducing the air velocity.

Even though we take temperature and pressure readings from the outdoor units, we sometimes fail to look for obvious non-equipment issues. Some yard cleanliness issues, such as vines or pet urine on the condenser, simply get overlooked. These issues may result in high head pressure and are usually more likely than refrigerant overcharge.

Overall, many systems have issues that can be solved with solid visual inspections and corrective measures beyond the equipment, such as addressing duct leakiness. When you troubleshoot better, you bring in more revenue for the company and increase your likelihood of getting a raise while keeping your customers satisfied.

Jim also covers:

Energy penalties in most HVAC systems
MeasureQuick and its limitations
Impacts of duct leakage on a home
What to check when cleaning condensate drains
Cleaning evaporators and condensers
Filter grilles
HEPA filters and pressure drop
Bad flex duct practices and sensible heat gain

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

How to Measure Total System Airflow w/ Steven Aug 05, 2021

In today’s podcast, Steven Rogers joins Bryan to talk about measuring total system airflow.

Fluid measurement is NOT restricted to liquids; a fluid is anything that flows, including liquids and gases. In HVAC, we deal with both of them, but airflow is strictly limited to the flow of gas. The airflow we experience in HVAC is exclusively turbulent flow, NOT truly laminar flow.

Total system airflow is difficult to measure directly; we can use flow hoods, but they have their limitations, especially on systems that have multiple returns. So, we measure pressures that give us clues about the airflow tendencies.

One of the most recognizable measurements is static pressure. Many factors can contribute to poor static pressure, including dirty filters and poorly designed supply and return plenums.

All measurements that you use to calculate static pressure will require an average. You take readings at multiple points of the duct, so you need to calculate an average value, whether you’re using static pressure tips, a hot wire anemometer, or a vane anemometer. Measurements are also particularly difficult to take in the supply registers, as there are almost no runs of straight duct.

Recently, the TrueFlow grid has come on the scene to make airflow measurement easier. The grid relies on torque and RPM data to determine the total system airflow. The TrueFlow grid slides in where the filter goes and measures the total system airflow. The grid works with an app that considers the system tonnage to let you know how good or bad the airflow is.

Bryan and Steven also discuss:

Bernoulli’s principle
“Moving” CFM targets
Flow hood limitations
Laminar vs. turbulent flow
Static pressure probes vs. pitot tubes
TESP and fan charts
Precision vs. typical manometer
TrueFlow grid vs. filter restriction
Water heater backdraft
Depressurization and combustion air zone

Check out The Energy Conservatory’s Website HERE. You can also check out the TrueFlow grid on that site or at HERE.

Check out our handy calculators HERE.

HVAC/R Career Advancement - Short 125 Aug 03, 2021

In today’s short podcast, Bryan explains how growth happens in an HVAC/R career. He also gives tips to get “unstuck” if you feel like you aren’t moving forward.

You won’t move forward if you haven’t set a goal to move forward. Making a “vision board” helps you determine what matters in your life, and it helps you clarify what you’ll need to do in order to achieve your life goals. That way, you can use your career to help achieve those goals and see whose support you need.

Having a growth mindset and a lifelong learning mindset is essential for success. The growth mindset will help you deal with the “growing pains” of advancement (such as occasional failures). People with positive attitudes also tend to see more possibilities for their future careers. On the other hand, negative people are likely to idle in their careers.

You also want to surround yourself with people who will bring out your best. It’s great to be around people who challenge you, have positive outlooks, and are happy for you when you make progress. Moreover, you want to be the person who is authentically excited when other people succeed and do good work. Also, try not to burn bridges with others.

To advance in your HVAC career specifically, develop your hands-on skills. Think about it this way: are you merely doing your job’s requirements, or are you working on yourself? Read through manuals and check out technical materials to become more literate with systems and do better work on them. Also, try to find a mentor who will help you grow. People skills are underrated in our industry but are critical for career advancement.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Mini-Split Controls Strategy w/ METUS Jul 29, 2021

In today’s podcast, Bryan and a team of Mitsubishi Electric Trane HVAC US (METUS) managers (Mike Schaefer, Charles Miltiades, and Sly Grimm) discuss mini-split controls strategies.

Some contractors misunderstand what mini-splits are. Mini-splits CAN be ductless, but not all of them are ductless. Mini-split systems also have handheld controls, but those are not the only control options for mini-splits. Mini-split controls also come in wi-fi, wall-mounted, and wired varieties.

Another common misconception about mini-splits is that they do not work in the cold. While that used to be accurate, modern mini-splits can function well as heat pumps that integrate backup heat. That is especially when it is also tied into a ducted system.

A lot of thought goes into sensor placement, and contractors have many options as to where they can be placed. You can put wireless sensors in discreet locations, such as under the air return in the basement.

Lately, there has been a market shift towards a preference for multizone equipment, so the wireless controls help manage several units instead of just one; you can manage 30+ indoor units.

In general, homeowners are becoming more tech-savvy and are beginning to prefer tying all of their HVAC systems together and managing them all via one platform. As such, Mitsubishi controls can connect to smart home assistants, such as Alexa or Google. Mitsubishi mini-split controls also work with a cloud service that remembers data. However, a strong wi-fi system is necessary for these controls.

The Mitsubishi Electric team also covers:

Third-party controls and backup heat
Integrating with boilers for primary heat
Control placement
Multizone controls
Smart devices and signal strength
Innovative solutions

Learn more at mylinkdrive.com and METUS’s YouTube channel.

Check out our handy calculators HERE.

Key System Performance Factors - Short 124 Jul 27, 2021

In today’s short podcast, Bryan discusses the key factors for system performance WITHOUT doing a deep dive into system commissioning. “Performance” refers to system efficiency, capacity, air filtration/cleanliness, longevity, and the ability to match the latent and sensible loads of a space.

System airflow is the main performance factor to consider. To determine proper airflow (CFM), consult Manuals S, J, and D to perform calculations. In general, the absolute lowest limit is around 275 CFM (in extreme dehumidification mode), and the highest limit should be around 525 CFM (in arid climates or at altitude).

You can determine your CFM target after you set up your ECM motor in the design. Then, you can also check airflow indicators: total external static pressure and pressure drop across the filter. The best way to improve airflow is to reduce pressure drop across the filter and build a better return plenum. For improving overall system performance, make sure the ducts are appropriately sized.

System charge is another important performance factor. There is a lot more to evaluating charge than checking the superheat and subcooling. If possible, it is a good idea to weigh the charge with a scale and see how it matches up with the line length.

In terms of long-term performance, the condenser’s location and cleanliness are also vital. Overall, a condenser works best if you put it in a slightly shaded area or on the north/east side of a building. The outdoor unit should also have some clearance from bushes and walls. Make sure the condenser is positioned away from pool equipment, water softener discharge, and dryer vent discharge. The goal is to keep the outdoor unit corrosion-free and able to “breathe.”

If you have an iPhone subscribe to the podcast HERE and if you have an Android phone subscribe HERE.

Check out our handy calculators HERE.

Copeland Scroll Compressor Multiples for Air Conditioning w/ Trevor Jul 22, 2021

In today’s podcast, Trevor and Bryan discuss Copeland Scroll Compressor Multiples for Air Conditioning. “Multiples” refer to equipment setups with multiple compressors that have connected suction and discharge lines, so they resemble parallel rack refrigeration setups. Multiples typically come in tandem (2) or trio (3) sets.

Compared to having a single giant compressor, multiples are more efficient, more reliable, and have the ability to keep running in case if there’s a compressor failure. As a result, we often use multiples in rooftop units, makeup air units, and chillers.

When you’re working on multiples or troubleshooting multiples, it’s okay to have sight glasses that indicate different oil levels. If you shut the compressors down and restart them, they should equalize. If you have a single compressor failure on a set of multiples, then you may have to replace both compressors in a tandem set; the manufacturer does not make single replacements for some tandem models. So, you can check the Application Engineering (AE) bulletin to determine your replacement needs.

Multiples may contain compressors of different sizes. Compressors of different sizes have different mass flow rates. In these cases, you would use a flow restrictor to balance the mass flow across the compressors.

On the refrigerant management end, the Copeland Scroll multiples will generally benefit from a crankcase heater. Correct location and installation of the crankcase heater are critical for proper functioning in multiples, and you can find that information in the manufacturer literature. Sometimes, you may also need an accumulator if there is a risk of refrigerant migration.

Bryan and Trevor also discuss:

Individual vs. multiple compressor manuals
Oil equalization lines
Compressor clamping
Variable speed motors and compressor variability
Sweating and flow restrictors
Maximum tilt
Adding oil
Torque values

Check out the AE-1430 bulletin HERE.

Check out Emerson’s HVACR training HERE. Then, navigate to “Contractor Tool Box Talks with Emerson.”

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Margin, COGS, Markup & Profit Confusion - Short 123 Jul 20, 2021

In today’s short podcast, Bryan clears up the differences between markup and profit margins in HVAC businesses.

The number one mistake that people make in business is confusing markup and gross margin. For example, you can double the price of a $50-part and sell it for $100. That would be a 100% markup. However, your gross margin is NOT 100%; your gross margin is only 50%; you only made a 50% profit on the total sale.

In the same case you have above, you have a 50% cost of goods sold (COGS). COGS is the direct cost of the expenses you paid to sell your service or product. The opposite of COGS is overhead. Overhead includes anything that doesn’t directly bring money to your business (rent, utility bills, etc.). Let’s say that your overhead costs total $30. You only end up with $20 of net profit.

Typically, 10-20% net profit is a good (if slightly idealistic) goal. Net profit can contribute to business growth if you put it into your business. For example, you can use that money for advertising, buying vans, and buying better tools.

If you want to determine a 10-20% goal, DO NOT USE MARKUP. Instead, you need to divide by your COGS expenses. In the case of the $50-scenario, let’s say that our cost of goods sold is 60%, so that seems like a 40% markup. You would divide 50 by 0.6, and you would get $83.33. If you multiplied by markup (140% or 1.4), you would have gotten $70. You wouldn’t come close to your gross margin number using the markup method.

Learn more about Refrigeration Technologies HERE.

Check out NAVAC HERE.

Check out SpeedClean HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Planning and Layout of HVAC Projects Jul 15, 2021

In today’s podcast, Eric Mele and Bryan explain the planning, layout, and execution of HVAC projects. They mostly cover commercial ductwork but also touch on piping and some residential projects.

Planning

The first step is to review the construction plan WITH a site visit. It is best to see how a plan works within the space; plans may be feasible on paper but may not work out as planned in the actual space.

During the site visit, you also want to establish solid communication with everyone else on the project. As such, it is best practice to have a coordination meeting with the general contractor and other trades (such as drywallers) to communicate potential areas of conflict. (When building ducts in commercial structures, you will want to watch out for conflicts with trusses, joists, fire sprinklers, and plumbing/drains. In residential structures, you will have to watch out for ventilation paths, such as dryer vents and kitchen exhaust vents.)

Before deciding to alter the design, be sure to communicate any possible alterations to the GC and other trades.

Layout

If possible, the next step is to lay out your construction plans on the floor. Constantly referring back to paper or digital plans is not productive. You can usually chalk up or spray paint the concrete at a construction site to draw your layout and plan the construction accurately within the space. The floor is also likely to be your best reference.

You can also use string to plot the locations where the hangers would go, especially if you have long runs of ductwork.

Execution

The first step of executing a project is preparing for hanging. When preparing for hanging, it is best to perform as much of the work on the floor as possible. The duct board can be stapled, taped, or masticed on the floor. Then, the hangers go up. If you have multiple people working on a project, one person can assemble the ducts on the floor and wait for the mastic to dry while another person puts up hangers.

You can usually wrap the ducts on the floor, and it is usually easier to do so. However, it is best to check with your GC before you do it. You may need the ductwork to pass an inspection.

When it comes to fasteners, you can use screws, flat strapping, or even aircraft cable. If using screws as fasteners, try to make sure that all of the screws have the same heads. Having to switch out drillbits for all the different screws is very inefficient. (As always, make sure your tools are easy to reach and in locations that won’t hurt your back. It is a good idea to have a toolbelt or workstation.)

When working with flex duct, make the takeoffs as easy for yourself as possible. You can use mastic as a seal for the collar instead of tape, as it may be easier to seal. (Either way, watch out for leaks.)

No matter what you do, make sure you’re taking care of your body, doing as much work on the floor as possible, and adhering to all applicable building codes.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Startup vs commissioning - Short 122 Jul 13, 2021

In today’s short podcast, Bryan explores the differences between startup and commissioning.

Startups typically involve going in during the construction phase after the drywall has been sealed up. (Vents, ducts, and copper piping typically go in before the drywall.) A technician can then perform a startup. The startup includes testing the drain line, checking the charge, checking for leaks, and seeing if the equipment performs its most basic function. (Does the gas furnace make flame? Does the A/C unit blow cold air?)

The startup’s goal is to get the equipment working. A startup does NOT focus on peak performance. A good startup will typically suffice for a cookie-cutter residential construction.

Conversely, the goal of commissioning is to optimize the equipment and test the advanced functions. Combustion analysis, airflow tests, and dehumidification tests all fall under the “commissioning” umbrella. Commissioning is where we use Manual S and Manual J to see if the equipment is appropriate for the home. Data collection, especially on sensible and latent capacities, is the core element of commissioning.

Commissioning also involves checking up on secondary functions, such as checking if heat strips activate during defrost. A custom construction plan will require commissioning to ensure that the equipment runs optimally in the uniquely designed space.

So, in short, equipment startup is about making sure the equipment works as it should on a basic level. On the other hand, commissioning uses data and specific instrumentation to make sure the equipment is running to its design and full potential.

Bryan also covers:

Stages of residential construction
Startup in new construction projects
Capping and filling drains
Who can perform a startup? (Junior techs, installers, senior techs, etc.)
Instrumentation for commissioning

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Make Mentorship Work w/ Eric Kaiser Jul 08, 2021

In today’s podcast, Eric Kaiser and Bryan talk about mentorship in the HVAC industry. They discuss what it means to be a good mentor, how to find a good mentor, and what it means to be mentored.

Mentorship is an organic process. Most mentees don’t go up to someone they respect and formally ask that person to be their mentor. Respect is the foundation of the mentor-mentee relationship; formal mentorship often resembles friendship in many ways.

However, mentorship can take more forms than the traditional mentor-mentee relationship. In the digital age, podcasts and YouTube channels that readily share information about a skill are resources that can fulfill the same role as a traditional mentor.

A good mentor has a willingness to explain the how and why behind a question or process; they don’t give simple answers. Good mentors must also be able to provide resources for their mentees; they know the limits of their knowledge and are willing to find those answers with their mentees. Often, the better mentors are humble and don’t flaunt their experience. Good mentors want to see their mentees do well and grow; they don’t want their mentees to follow and copy them.

The support in the relationship goes both ways. The mentee must want to support their mentor, not compete with them. Mentees must be willing to start conversations and ask for clarification; an ineffective mentee waits for answers to be spoonfed to them. Good mentees are also willing to challenge their mentors at times [respectfully]; they don’t excessively flatter their mentors.

Bryan and Eric also cover:

Personal growth
Online mentorship resources
Cultish mentors
Outgrowing and leaving mentors
“Stealing” in mentor relationships
Unproductive mentorship
Honoring mentorship

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Alternatives for College That Parents Should Consider Jul 01, 2021

In today’s podcast, Bryan explores the upsides of choosing a career in the skilled trades instead of going to college. He also covers ways to prepare your child for a trades education and career while they are still deciding what to do with their lives.

When we think about what we want for our kids, the following goals come up quite often: purpose, financial upside and reward, freedom from debt, and joy. The trades can offer a lifestyle that covers all of these bases. However, the opinions of our friends and the fear of failing as a parent may prevent us from encouraging our children to enter the trades.

Going to college has plenty of downsides, such as saddling students with debt and not guaranteeing opportunities to move forward in a career.

Alternative career paths include the HVAC/R trades, electricians, off-grid solar technicians, and so on. Your child will learn hard skills on these career paths that are easily transferable. These trades also generally have plenty of apprenticeship opportunities. In the case of HVAC/R, technicians may also have the opportunity to earn a lot more money in only a few years. At that rate, they will have ideally saved some money to go to college later on if they believe that college is truly the right choice for them.

Bryan also covers:

The desire for purpose and impact in a career
Doing good work vs. being seen doing good work
Advantages and disadvantages of college
The societal obsession with certificates of completion
How to avoid feeling “stuck” as a young adult
What it means to have a high opportunity/learning ceiling
Interesting and meaningful problem-solving in a career
Acquiring hard skills
Diversity of challenges in a career
Strong lateral problem-solving skills
Advantages and disadvantages of home education
Autodidactism
Alternative career paths with financial and personal upside

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Triple Evacuation - Short 121 Jun 29, 2021

In today’s short podcast, Bryan explores triple evacuation. Many people believe that we don’t like triple evac, but that’s simply NOT true. We’re here to set the record straight.

If the manufacturer tells you to follow triple evacuation processes, then it’s a good idea to do what they say. We won’t argue with that. However, our argument is that the procedure can be more time-consuming than it’s worth when it’s NOT necessary.

Deep vacuum technically counts as a vacuum pulled below 500 microns (in residential, that target is usually 200-300 microns). Most modern micron gauges and tools make it easy to achieve a deep vacuum. In a triple evacuation, you pull the vacuum three times (instead of once). Between pulling vacuums, you break with nitrogen before pulling the vacuum back down.

Triple evacuation originated in a time when micron gauges and vacuum pumps were less reliable. We did not take deep vacuum very seriously, especially since mineral oil (MO) typically did not break down inside the system. (Modern oils like polyolester/POE break down rather easily, so pulling a deep vacuum is much more vital nowadays.)

Instead of merely breaking with nitrogen, Bryan recommends flowing it. It’s best to flow the nitrogen with force to move the oil around more effectively. In turn, your vacuum will pull down more quickly and efficiently.

So, triple evacuation isn’t bad, but it can be time-consuming. Just be sure to follow all best practices if you perform a triple evacuation.

Join us as we cover:

Deep vacuum targets
Micron targets
Breaking with nitrogen
Flowing nitrogen
POE vs. mineral oil
Old manufacturer literature about deep vacuum
Microns

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

How to Teach the Physics of Everyday Life Jun 24, 2021

In today’s podcast, Bryan explains how he teaches physics. He believes that teaching physics is about continuously building a mental model, and he covers the methods and mindsets that facilitate that learning style.

The basic Wikipedia definition of physics states that it is a science that deals with matter, energy, and their interactions. Even then, we can simplify “matter” to “stuff.” Simplifications like these help students feel more familiar with the subject and NOT feel intimidated by the material. Students learn best when they feel like they can grasp the topics out of the gate. That is why the math-based approaches of traditional education might turn students away from physics. Some students who don’t like math might feel out of their depth when teachers approach topics with a mathematical approach.

Instead, effective teaching is about attaching experiences to a concept. Teachers can take stock of what students already know and build on that. They can also attach experiences to a concept, such as by allowing students to have hands-on experiences with physics examples in the real world. Once students have relevant experiences, they have the tools to learn through similes and analogies.

Bryan covers:

Socratic learning
Comparing levers to seesaws for educational purposes
Experimentation and experience
Similes, metaphors, and analogies
Shortcomings of math-based learning methods
Creating “cartoons” in your head to learn topics
Teaching superheat and subcool with mental “cartoons”
States of matter
Humidity and the weight of water vapor
Electron movement
Steam and why it’s complicated
Teaching electricity with comparisons (water, drawbridges, jump ropes)
How children (and babies) learn about physics as they navigate the world
Mythbusting

Remember, when it comes to education, the goal is to learn, NOT to impress people.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Be Careful With Cold Tanks - Short 120 Jun 22, 2021

In today’s short podcast, Bryan explores the dangers of cold tanks during refrigerant recovery.

Whenever you have a recovery tank, you only want to fill it to 80% capacity in the liquid state. The same goes for all sorts of vessels (coils, etc.).

However, capacity isn’t the only factor to consider for safety. We need to know what our maximum temperature will be. You will be in greater danger of overfilling a tank when it is cold because higher temperatures increase the pressure. High pressure in a closed space may lead to explosions. When you fill a tank to 80% under cold conditions, normal temperature conditions could put you in the danger zone (let alone temperatures above 100°F).

So, it’s better to determine your tank fill based on densities at the MAXIMUM temperatures you will encounter, NOT for the measurements at artificial cooling conditions (such as when you put the tank in ice water during recovery).

In the end, just be careful when you’re recovering into a cold tank or using tanks when it’s cold outside. That will help you avoid hydrostatic pressure buildup and explosions.

Bryan covers:

The 80% capacity rule for filling vessels with liquid
Why the 80% capacity rule varies by temperature
Temperature, pressure, and density
Hydrostatic pressure
AHRI’s 77°F guideline
Ice buckets for recovery
What to do if a tank vents its refrigerant on you while driving

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Dehumidification Facts w/ Nikki Jun 17, 2021

In today’s podcast, Nikki and Bryan discuss dehumidification. They cover the relationship between cooling and dehumidification, humidity control, and dehumidifier installation practices.

If the A/C unit is the king, the dehumidifier is the queen. The A/C unit controls cooling and humidity, but it can only do so much. A dehumidifier helps the A/C manage comfort under more demanding conditions. Many factors contribute to comfort, including sensible heat ratio (SHR), relative humidity (RH), and ventilation. Dehumidification reaches all of those factors.

Humidity control requires a holistic approach. Band-aid fixes DO NOT work. Dehumidifiers should work with the A/C system and building design to keep RH in the 50-55% range. Proper installation is vital. For example, tying into the HVAC supply is a recommended practice. Returns are the opposite; dedicated returns are preferred. Other factors to consider are proper sizing, Manual J, and customer expectations.

Join Nikki and Bryan as they cover:

Relative humidity targets
Sensible heat ratio (SHR)
Latent removal capacity
Ventilation
Building design and tightness
Manual J
Challenges with ductless systems
Ducting into the supply with dedicated returns
Installation practices
Dehumidifier sales and customer service

And much more…

To learn more about Santa Fe Ultra series, go to www.santa-fe-products.com. You can scroll through the products to find the Ultra series free-standing ventilating dehumidifiers.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

TXV Troubleshooting w/ Trevor Jun 10, 2021

In today’s podcast, Trevor and Bryan discuss how to troubleshoot thermostatic expansion valves (TXVs/TEVs). They also dive into the various types, applications, and components of TXVs.

TXVs are metering devices that control evaporator superheat to protect compressors from harm. Controlling heat also regulates pressure, which improves efficiency and prevents issues like floodback and overheating. TXVs contain several components that manage the forces that open and close the valve. These components include powerheads, diaphragms, springs, and more. The components all contribute to a delicate balance that can be broken when they fail or are installed improperly. TXV failures lead to high or low superheat and eventually compressor failure.

When you diagnose a TXV, you may encounter hunting, broken powerheads, filthy screens, and improperly sized valves. Once you verify the cause of the issue, you’ll likely have to adjust the TXV, replace a component, or replace the whole TXV. That can be a tricky decision that will largely depend on the type of failure, the type of TXV (conventional vs. balanced port), and the TXV’s application (residential HVAC, refrigeration, etc.).

Join Bryan and Trevor as they cover:

Opening and closing forces
Internal and external equalization
Non-bleed/hard shutoff TXVs and design limitations
Conventional valves vs. balanced port valves
Brazing in TXVs
Strapping the TXV bulb to the suction line
TXVs in refrigeration vs. HVAC
Liquid quality, sight glasses, and subcooling
TXV sizing
Suction pressure/superheat hunting
High and low superheat causes
Adjusting vs. replacing valves

And much more...

Check out Emerson’s HVACR training HERE. Then, navigate to “Contractor Tool Box Talks with Emerson.”

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Push Pull Recovery - Short 119 Jun 08, 2021

In this short podcast episode, Bryan discusses push-pull recovery, how it works, and what we need to know about it.

Push-pull recovery is a somewhat counterintuitive method of recovering liquid rapidly. We simply do that by pulling refrigerant out of the system and pushing it into the tank. However, when we pack refrigerant into a tank, the tank pressure and temperature increase. So, it can be more difficult to get refrigerant into the tank as the job goes on.

When we recover liquid refrigerant on large systems (20+ pounds of charge), you connect a line from the liquid line or receiver and attach it to one side of the tank. Then, you pull from the system the other side of the tank should lead into the recovery machine. Attaching to the recovery machine helps depressurize the tank.

When pulling out of the tank, you'll want to make sure the refrigerant is a vapor. The recovery machine should be pulling only vapor refrigerant out of the tank. While you're depressurizing your tank, you will be pressurizing your system to push the liquid refrigerant out of the system and into the recovery tank. (Short hoses with a large diameter are usually best for quick recovery.)

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Check out our handy calculators HERE.

Small System Vacuum Tip - Short 118 Jun 01, 2021

In this short podcast episode, Bryan goes over one of his most valuable tips for pulling a vacuum on a small system.

It can be very difficult to pull a vacuum on a small system, especially when you're dealing with a low-temperature application like a freezer. When you pull a vacuum, you're creating a low-pressure area that affects molecule behavior. So, you're creating a situation where the molecules push their way out of the system and into your vacuum pump. The low temperature and small tubing, especially capillary tubes, make this process exceptionally difficult. A very good vacuum pump can still have a hard time achieving a deep vacuum.

To make this process a little easier, Bryan likes to add heat. When you add a heat blanket around components with oil, you negate the low-temperature obstacle and make it easier to separate refrigerant from oil. You may also use a heat gun on areas where using a heat blanket is impractical. If the area is cold or has refrigerant and oil together, then you'll benefit from applying heat. Don't go crazy and use open flames, but a heat blanket or heat gun will usually be safe.

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Check out our handy calculators HERE.

How to END Callbacks May 20, 2021

In this podcast episode, Bryan and Eric Mele explain how HVACR technicians can END callbacks with a few best practices.

Rushing through calls will often lead to callbacks. One of the most common mistakes techs make is failing to check the condensate drain before walking away from a job. To end callbacks, technicians would be wise to check the entire system and note any possible problem areas; in commercial HVAC and refrigeration, pay attention to variation across evaporators, condensers, and drainage systems.

Customer service is a huge component of residential HVAC; you can prevent callbacks by listening to the customer's concerns, addressing their comfort issues (even if it lies beyond the obvious problem), checking your "five pillars," and thoroughly explaining what you've done. Even if a problem seems to drag out, take all the steps necessary to alleviate your customers' fears.

Electrical problems also cause callbacks, especially dual-run capacitors. So, it's a good idea to check for wiring rubouts and make sure the wires look clean and organized. If you can offer an electrical solution to the customer at a cost, do it, even if they might decline it; that way, the callback is on them, not you.

Overall, being thorough, communicating with the customer, and offering solutions is the key. If possible, it's best to explain everything at once and have one money conversation. If you can't get a full diagnosis until the customer approves a repair, be transparent about that.

Eric and Bryan also discuss:

Multi-equipment setups in commercial settings
Dealing with difficult customers
Managing customers' expectations
HVAC in new homes
Determining if a unit has been set up correctly
Smart thermostats
Cleaning drains and equipment
Preventing flooded starts
OEM vs. aftermarket parts
Commonly replaced parts (reversing valves, TXVs, etc.)
Establishing a process that works

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Compressor Overheating Diagnosis & Prevention May 13, 2021

In this podcast episode, Bryan and Eric Mele discuss the diagnosis and prevention of compressor overheating in HVAC and refrigeration.

The main causes of compressor overheating are inadequate cooling back to the compressor, low charge, restrictions, and sometimes even poor suction line insulation. We want to keep the suction temperature low while maintaining appropriate superheat. If the suction line temperature is too high, the compressor can't cool down well enough. Dirty condenser coils, low voltage, weak capacitors, or an inadequate condenser fan can also lead to compressor overheating.

Electrical problems, including too little capacitance, will make a compressor go out on thermal overload. When you have refrigerant problems, the thermal mass will just keep growing; it takes a long time to heat the compressor up, and it will take a long time to cool it down.

In a thermal overload, a bimetallic disk in the compressor will open and break all three legs of power. When a compressor goes out on thermal overload, it will make an open circuit, and you will read infinite ohms. Knowing that the compressor has gone out on thermal overload is just the beginning of compressor overheating diagnosis.

So, to begin diagnosis, you'll want to make sure there's refrigerant in the system. Inspect the unit visually and note anything that seems odd. Then, you'd check your capacitor for electrical problems. You can also feel the compressor to get an idea of the extent of the overheating (try not to burn yourself). You'll also want to monitor the amp draw, condensing temperature, suction pressure, and superheat.

Eric and Bryan also discuss:

Axial fans
Condenser fan intermittent failures
Resetting the compressor
Cooling down the compressor
Setting up your meter
Being out on high pressure
Wrapping wire to increase ammeter resolution
High return gas temperature

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Re-tapping Transformers - Short 117 May 11, 2021

In this short podcast episode, Bryan and Eric Mele talk about re-tapping transformers for single-phase equipment in 208v applications.

Most single-phase equipment can work for 230v or 208v, meaning that they can operate with low voltage. However, we typically see 208v in commercial buildings. The sine waves of 208v equipment are 120 degrees out of phase, not 180 degrees (as in split-phase applications). We get lower voltage from leg to leg (208v, though the voltage can be a little higher or lower). Power companies generally put out slightly higher voltage to reduce line losses.

Most systems can work on multiple voltages, but they come with a transformer that's set to the 230v or 240v setting. However, under those settings, you can experience issues in 208v applications. If you put equipment tapped to 230v or 240v in a commercial setting, you may have issues, especially if you're farther away from the air handler. You may not get full 208v and may see contactors that don't pull in intermittently, and you may get intermittent cooling calls. Intermittent problems become worse when you have long thermostat wiring.

In those cases, re-tapping the transformer is your only option. When the original voltage is incorrect, you'll need to re-tap the primary (high-voltage power going in). If you fail to tap the primary correctly, the voltage going out of the secondary won't be correct. When it's time to test the equipment, you'll always want to be sure to test the equipment under load.

Make sure you cap extra wires and cap them independently of each other; those wires do have voltage, and we need to be cognizant of that.

Learn more about Refrigeration Technologies HERE.

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Check out our handy calculators HERE.

Indoor Air Quality Map & Compass w/ TZOA May 06, 2021

In this podcast episode, Ben Reed from TZOA, a disruptive air technology brand, joins us to discuss the indoor air quality map and compass.

We spend a majority of our lives indoors, so TZOA tries to improve IAQ in homes to keep us healthier. HVAC manages airborne chemicals, so indoor air quality ties right into our industry; HVAC technicians will become more valuable when they become well-versed in IAQ technologies.

In residential HVAC, we are already used to listening to customer complaints and observing the home. Technicians (and even IAQ products) can "map" out the customer concerns and home features to develop a comfort and home-health solution. TZOA is working on putting together that "map and compass" model to optimize home health and comfort by noting problem areas and pointing us to the tools to solve the problem.

HAVEN uses a central air monitor (CAM), which is an in-duct, whole-home IAQ monitor that measures particulates, temperature, and humidity. The monitor pairs with software to fulfill the "map and compass" model and assist with diagnosis. The air monitor and software help dispel uncertainty around IAQ products while providing accurate readings that point to solutions.

It's also worth noting that HAVEN's tools can only be purchased and installed by HVAC professionals. So, they're helping bridge the communication gap between technicians and customers. TZOA is also attempting to build trust and confidence in IAQ products through education, collaboration with industry experts, and allowing HVAC technicians to use and experiment with their products.

Ben and Bryan also discuss:

HAVEN and TZOA's beginnings
IAQ uncertainty and reputation
Multiple chemical sensitivity
Ventilation and dilution
The future of TZOA products
TZOA's personal use program
Working with reputable companies and people
Integrating IAQ into maintenance plans

Learn more about TZOA and HAVEN at haveniaq.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Copeland 2-stage ZPS Scroll Compressors Apr 29, 2021

In this podcast episode, Bryan and Trevor Matthews of Emerson Canada discuss the Copeland 2-stage ZPS scroll compressors. Please join us by following along in bulletins AE4-1428 and AE4-1365.

The ZP91KCE to ZP143KC Copeland compressors don't have internal pressure reliefs (IPRs). Those higher-pressure compressors make very loud noises when they go off, and it'll blow hot discharge gas on the internal overload to shut down the compressor. Some scroll compressors have temperature operating disks (TODs), which are bimetal disks that open upon a temperature increase and reroute the gas. Other compressors have advanced scroll temperature protection (ASTP), which is a snap-back disk near the floating seal.

You don't just want to shut the suction service valve to pump the scroll down. Instead, common service procedures include checking voltage to the compressor, the internal motor, the blower/fan operation, the suction pressure, and the compressor wiring.

If you install crankcase heaters for oil management, be sure to install them correctly to avoid overheating the compressor. You'll also want to verify that crankcase heater voltage and ensure that it is properly grounded.

Two-stage modulating Copeland scrolls work with a 24v DC solenoid in the scroll set. That solenoid energizes and de-energizes, which either fully or partially loads the compressor. Load matching is ideal for efficiency and comfort, meaning that the two-stage Copeland scrolls perform well in those areas. Unsurprisingly, the fully-loaded option draws more current than the partially-loaded option. These two-stage compressors don't have IPRs, so you will need a high-pressure control set to 650 PSI.

Trevor and Bryan also discuss:

TOD vs. ASTP
Operating envelopes
Hipot testing
Single-phase compressors
Using Copeland compressors in pool heaters
Oil and refrigerant dilution
Wiring up CoreSense
Reversing valve sizing issues

Visit climate.emerson.com for more resources.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Screw Compressor Talk w/ Vilter Apr 22, 2021

In this podcast episode, Bryan, Trevor Matthews, and Jim Dick of Emerson talk about the screw compressor and how it works. This time, they focus on the Vilter single-screw compressors.

Vilter is an industrial compressor division of Emerson (compare to Copeland). Vilter also makes reciprocating compressors, but the screw compressor is its claim to fame; you may want to consider using a screw compressor when you want greater capacity and control than a reciprocating compressor. Screw compressors also work well for applications with constant loads; they do, however, have microprocessors that can monitor system performance to maximize efficiency.

Vilter uses a compressor with a single screw, whereas most compressors have twin screws. Twin screws have a motor that continuously turns the rotor, which causes the screws to mesh together; the compression happens as gas fits between the screws, and the gas volume decreases as the space between the screws closes. In a single-screw compressor, the gas compresses on the outside of the screw. In any case, we must seal the gas in the flutes, and oil helps us with that. Liquid should not get into either type of screw compressor, as liquid is not compressible and will damage the compressor.

When you service a screw, the oil temperature and discharge pressure will likely be the most important values to watch out for. During maintenance inspections, you'll also want to pay special attention to the bearings, the four pressure transducers, and oil filtration system.

Jim, Trevor, and Bryan also discuss:

Microprocessors
Star rotors
Oil uses, management, and components
Motor RPM
Multiple compressors and added capacity
Calibrating pressure transducers
Zeroing vs. calibrating
Suction screens
Jim's interesting findings
Injecting oil
Value engineering and consistency

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Condensation Problem Solving - Short 116 Apr 20, 2021

In this short podcast episode, Bryan talks about condensation and how HVAC technicians can solve condensation-related problems. He also discusses humidity control and how that can affect sweating.

We may have heard the phrase, "Condensation is where hot meets cold." That's not necessarily true; while it may seem that sweating happens where hot meets cold, the dew point is the main cause. We won't see condensation unless we have air that reaches the dew point. When air flows across surfaces that have a temperature below the dew point, you'll start to see sweating on the surface.

Clouds and fog indicate liquid water in the air; if you see fog, then you will know that the ambient temperature is below the dew point. We also can't see steam; steam is water vapor, but the "steam" we see is actually liquid water. Water vapor is also lighter than air, so it rises in the vapor form.

When we see condensation or sweating, we must ask ourselves if the surface is colder than it's supposed to be. Ducts can sweat when the airflow is too low, and the air handler can sweat when the evaporator freezes. If we were to heat the air as a solution, we can decrease the relative humidity, but heating the air doesn't change the dew point or total moisture content.

The next step is to make sure we don't have infiltration at boots or can lights. Infiltration can cause sweating, especially in unconditioned spaces. You'll also want to make sure that the duct insulation is straight and that the ducts have been properly strapped. The house itself can also cause infiltration, especially through fireplaces and chases; a blower door test can help you determine the leakiness of the home. Ventilating dehumidification may also work as a solution.

Check out Richard Sims's presentation on our YouTube channel HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

ECM Types and Applications Apr 15, 2021

In this podcast episode, Bryan and Chris Mohalley of Regal Beloit discuss the different types of ECM. They also cover applications where you can expect to find ECMs.

In the HVAC industry, we typically use three types of motors: constant-torque, constant-airflow, and constant-speed. Every ECM works on electronic commutation, so constant-torque motors use that to maintain torque output (X13). The constant-airflow motor is also known as the variable-speed motor, and it is one of the first ECM types. We typically only use constant-speed motors in outdoor fan motor applications. Likewise, we generally use the first two motor types for indoor fan motors inside air handlers.

ECMs were NOT designed to address the static pressure problems of PSC motors and duct issues; variable-speed motors may attempt to compensate for duct problems, but that's not its purpose. (Variable-speed motors work like cruise control in a car.) However, when motors compensate for poor duct systems, they could run higher RPM than desirable in order to hit the system targets and can generate excess heat.

Constant-torque motors maintain a certain torque value, which can get tricky when the loads begin to vary. When static pressure goes up, there's less air in the system, which means that there's less air for the wheel to move (a smaller load). Current and RPM can increase when static pressure goes up, but the torque would stay the same.

Chris and Bryan also discuss:

What is a variable-speed motor?
Permanent split capacitor (PSC) motors
Duct sizing and design
Static pressure and motor life expectancy
Reactive power and power factor
Torque vs. speed taps
Blower performance curves
Different series of motors
PWM (pulse-width modulation) and inputs
Setting DIP switches
Evergreen VS
Why should you read the manual?

Check out some more ECM resources at regalmmu.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Right and Wrong Way to HVACR w/ Eric Kaiser Apr 08, 2021

In this podcast episode, Bryan and Eric Kaiser discuss the right and wrong way to do HVAC/R jobs and approach HVAC/R work.

Breaking things down into "right" and "wrong" categories is a rather simple way to approach a problem; we throw nuance and alternatives out the window, which can be worse than doing something "wrong." Instead of viewing things as right and wrong, we would be better off if we looked at our objectives and focused on solving problems instead of being right.

Although there are surely correct ways to pull a vacuum, it's more useful to set standards than argue about what's right. Set standards that are appropriate for the situation (the equipment, your tools, your skill level, etc.). Of course, it would also be best if we could try to set our egos aside. We need to have humility and acknowledge that we're all trying to improve for the sake of our customers. That said, we could all benefit from focusing on achieving successful outcomes instead of being "right."

Ultimately, many of our struggles to determine right from wrong can be solved by listening to the customer. Our goal is to tailor our practices to our customers' needs, even in commercial work where customer service isn't as important. Being overly dogmatic doesn't do much to help a customer, and it fails to account for the unique details of each situation we encounter in the field.

Eric and Bryan also discuss:

The right vs. wrong way binary
Maturity
Situational awareness
Evacuation best practices
Customer discretion and expectations
Do aesthetics matter?
Commercial vs. residential HVAC
Evaluating suppliers and manufacturers reasonably
How oil and parts have evolved
Flowing nitrogen
Setting goals

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How EC Motors Work Apr 01, 2021

In this podcast episode, Bryan and Chris Mohalley from Regal Beloit discuss EC motors. They also describe ECM applications and how those motors work.

EC motors (ECMs or "ECM motors") are electronically commutated motors. These motors are generally three-phase AC motors operated by a drive; that drive is a combination of an AC-to-DC converter, microprocessor, and frequency drive. So, the frequency delivered to the motor is generated electronically.

When it comes to inputs, the ECM works like a printer. One input provides power (from the wall to the printer). The other cable tells the printer what to do and when to do it (from the computer to the printer). An ECM will have a line voltage connection and a constant 24v communication input. Constant-torque ECMs work like PSC motors in the way they use control taps; other ECMs may use DIP switches.

ECMs are direct-drive motors that differ from PSCs because they don't have a capacitor. EC motors also have a permanent magnet, which can affect diagnosis if you rarely come across indexing.

AC motors use magnetism; when you pass energy through the stator coil, the coil creates an invisible magnetic field, which then induces a magnetic field into the rotor. When the rotor picks up a magnetic effect, it starts to spin. EC motors have that magnetic effect in their magnets.

Chris and Bryan also discuss:

Regal Beloit's history and brands
Effectiveness of metaphors and acronyms in our industry
Constant-torque ECM vs. variable-speed motor
Motor modules
Changes to the ECM design over time
ECM manufacturers
Three-phase power and controls
Reading ohms
Glued-on vs. slotted magnets
RPM and the effects of poles and frequency of power delivered

For more resources for EC motors, check out regalmmu.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Stacking Liquid vs. Mechanical Subcooling - Short 115 Mar 30, 2021

In this short podcast episode, Bryan compares strategies for increasing the subcooling, including stacking liquid and mechanical subcooling.

Subcooling is a consequence of condensing; when we change the refrigerant from a vapor to a liquid, it will drop below saturation temperature after it becomes completely liquid. There are three phases in the condenser: desuperheating, condensing, and subcooling. The first few rows of the coil reduce the superheat of the vapor entering the condenser. Once there is no more superheat, heat rejection helps the saturated refrigerant transform into a liquid entirely. Near the end of the coil, liquid refrigerant can keep losing heat, and it becomes subcooled.

We can only achieve subcooling by stacking liquid in the condenser. When you stack liquid in the condenser, it can give off its heat to the outdoor air. However, too much subcooling isn't necessarily a good thing. Your condensing temperature should be above the outdoor temperature; we call this value the condensing temperature over ambient (CTOA). When your condensing temperature is too close to the ambient temperature, you won't get much heat rejection.

If your subcooling goes up because you're stacking too much liquid, you'll drive up your CTOA and head pressure. If you increase your head pressure, you'll increase your compression ratio. Your efficiency will suffer. So, when stacking liquid, you'll want to find a happy medium. However, in systems with liquid receivers, you may not see much liquid stacking at all.

Getting some extra subcooling can boost your system capacity. We have some mechanical subcooling devices that use heat exchangers to drop the temperature of the refrigerant in the liquid line. That way, the refrigerant can absorb more heat when it's in the evaporator coil.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Proper Design For Ductless and Ducted HVAC Systems Mar 25, 2021

In this podcast episode, Bryan, Chad, John, and Allison discuss proper design for ductless and ducted HVAC systems, especially mini-splits. They also discuss potential future improvements to equipment and duct designs.

Mini-splits are smaller than traditional HVAC units, so they make zoning a bit easier. However, load calculation plays a huge role in equipment selection and zoning because you must get the right number of zones to match the equipment capacity and meet your load requirements.

Proper design is difficult, and a common mistake includes using one piece of equipment to serve the whole house, especially on new constructions. Some designers also don't offer multiple options to the customer, which can be a mistake. Most of the time, we end up downsizing systems, not making them larger. Failing to smooth out turns in the ducts and use proper fittings can also negatively affect airflow and pressure. If you're working on new construction, you'd be best to get an idea of the building design ahead of time and clearly communicate what you need to create a proper duct design.

Going from traditional to mini-split duct design has a bit of a learning curve. It's easy to make mistakes when you aren't prepared to deal with the function of variable capacity in mini-splits. You can avoid making mistakes by learning about the equipment (and duct materials) during the selection process, not after the selection.

Chad, John, Allison, and Bryan also cover:

Adjusting the structure
Replacing old equipment with higher-SEER equipment
Selecting filters and filter grilles
Static pressure options
Total length vs. total equivalent length
Register sizing
Flex ductwork
Drop ceilings
Texas's energy grid and how it relates to potential setbacks
Replacing furnaces with heat pump systems
Future micro-split heat pumps

Check out energyvanguard.com and think-little.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Atmospheric Pressure - Short 114 Mar 23, 2021

In this short podcast episode, Bryan explains what atmospheric pressure really is, pressure units and conversions, and why those are matter.

Atmospheric pressure is the weight of the air around us pushing down on us. We normally see that value expressed as 14.7 PSI (or 0 PSIG). Before we dive too deep into atmospheric pressure, we should understand some basic pressure units.

We may see pressure expressed in microns when we're pulling a vacuum; we are trying to pull the atmosphere out of the system, so our goal is to get as close to 0 as possible. Whenever we pull a vacuum, we get liquid water to boil off and remove molecules inside the system. The industry standard is 500 microns. 14.7 PSI(A) is equivalent to about 760,000 microns, so the micron is an extremely small pressure measurement. You may also see the bar scale, which is equivalent to 1 atmosphere (atm). One bar equals just over 14.5 PSIA.

You may also encounter the Pascal unit, which is common on the building science side of our industry. One PSI is equal to 6,894.76 Pascals. When we look at small pressures, such as static pressure or gas pressure, we may use the inch of water column ("wc). One inch of water column is equal to 248.84 Pascals. We also have inches of mercury ("Hg) and the torr (mmHg), which are related to the micron. All units are interrelated, but they have their appropriate applications.

Atmospheric pressure matters when altitude enters the equation. When the pressure changes at a higher altitude, the air density also changes. The air is less dense, so you have less oxygen in the air. When you have less oxygen in the air, combustion is more likely to be incomplete. So, we may need to derate furnaces. We also need to take altitude into account when we calibrate gauges at significant altitudes compared to sea level.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Diagnose and Prevent Compressor Short Cycling Mar 11, 2021

In this podcast episode, Bryan and Trevor Matthews discuss compressor short cycling. They discuss how to diagnose and prevent that issue. Trevor and Bryan primarily refer to the Bulletin AE17-1262 throughout this episode, which you can find HERE.

Compressor misdiagnosis is very common, but we generally encounter two types of compressor failures: electrical failures and lubrication failures. Short cycling causes a loss of oil in the compressor, which may lead to lubrication-related failure. Each time a compressor starts, there is a reduction in suction pressure; the pressure drop then causes the saturation pressure to drop. That can then cause the oil to flash and shoot out of the compressor.

Short cycling has many potential causes, including protectors, thermostats, low and high-pressure controls, oversized condensers, and oversized compressors. In some cases, the controls can also cause operational short cycling to meet customer demands (or failure to match the load). Each manufacturer may have a different acceptable range of starts per hour, but some customers may request more or fewer starts than recommended.

Cycle length and frequency are keys to system longevity. So, we can prevent compressor short cycling by keeping the system operating within the manufacturer's specs. There are also several components that can help manage the factors that cause short cycling, including bleed resistors on capacitors, which manage relay operation. Troubleshooting is also one of the main preventative measures; if you replace the compressor without troubleshooting, your new compressor may short cycle and fail prematurely just like the first one.

Trevor and Bryan also discuss:

Oil behavior and losses
Customer demands
Manufacturer specs and communication
Oversized compressor issues
Internal low-leak discharge check valves
Digital scroll compressors in a tandem set
Short cycling's effects on the whole system
Airflow and pressure
Load matching

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Recovery Tips and Best Practices w/ AC Service Tech Mar 04, 2021

In this podcast episode, Bryan and Craig Migliaccio (AC Service Tech) discuss some HVACR recovery tips and best practices.

When you select a recovery tank, you need to know which refrigerant is in the tank. So, it's a good idea to make sure you label each recovery cylinder. You don't want to contaminate refrigerant in the recovery tank, use a recovery tank with contaminated refrigerant, or have too much air inside the cylinder. If the tank is empty, you'll have to pull a vacuum on it before you use it for the first time.

Tank fill can be a tricky business. You have the tare weight and water capacity, which you can use to determine the maximum refrigerant fill (factoring in the refrigerant's specific gravity at 130 degrees and the 80% capacity). Weighing in the charge is important so that you stay within an appropriate range as not to build up hydrostatic pressure and risk injury.

Recovery machines will give you the quickest recoveries. (When using one of those, you can extend your machine's life by using a filter drier during recovery.) However, you can also keep the pressure of the tank low during recovery; one of our best tips is to put the cylinder in an ice bucket during recovery. Regardless of what you use for recovery, you ALWAYS want to use a scale to weigh the tank as you recover refrigerant.

Craig and Bryan also discuss:

Hydrostatic pressure
Figuring out the refrigerant type in an unmarked tank
Contamination
Core removal
Waterproof scales
Leaks and low refrigerant charge conditions
Pulling from the liquid and suction lines
De minimis venting

Check out Craig's website at acservicetech.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Swaging and Flaring Tips w/ AC Service Tech Feb 25, 2021

In this episode, Bryan and Craig Migliaccio (AC Service Tech) talk about some best practices you can use while swaging and flaring copper.

There are a few different ways you can flare copper. Craig likes using a round deburring tool before flaring the copper. After the burr has been cleanly removed, Craig likes using an eccentric flaring tool for the actual flaring. Bryan's favorite flaring tool is the NAVAC battery-powered flaring tool for quick, accurate flares. Both Craig and Bryan agree that it's better not to deburr if you're likely to drop the burr or copper shavings into the tubing.

You can also use a tiny bit of Refrigeration Technologies Nylog on the flare face to make sure that the contact is sufficient and secure.

Along with flaring, we also have tube expansion or swaging. There are several tools you can use, including drill, hammer, and block swages. Craig likes to avoid swaging tools that leave large gaps; adding heat to make the swaging process smoother may result in oxidation. He prefers using a drill swage on downward-facing tubes; the drill swage can provide friction and heat while keeping the copper tube clean. Overall, Craig doesn't have a favorite swaging tool; he acknowledges that each swaging tool has an appropriate application. It's NOT a good idea to use a tube expander near the compressor.

Craig and Bryan also discuss:

Deburring in difficult situations
Over-reaming with blade deburring tools
Flares on higher-pressure systems
Comparing the flare size to the flare adapter size
Old flaring tools, new flares
Ductless or mini-split systems
Cleaning the lines if you drop anything inside of them
When to use a fitting

Check out Craig's website at acservicetech.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Are Contactors Obsolete? (SureSwitch) Feb 24, 2021

In this podcast episode, Bryan and Jim Fultz discuss the White-Rodgers SureSwitch and determine whether contactors are obsolete or not.

Contactors are electrical controls; they started off very expensive and usually outlasted equipment, so they are currently smaller, cheaper, and less durable than they used to be. Modern contactors have open contacts and are susceptible to insect damage. Sometimes, an electrical arc can cause contactor pitting, which can weld the points together and render the contacts useless.

The SureSwitch is more than a contactor; it is also a brownout monitor, short cycle timer, and a random start timer that helps with brownout recovery. The installation instructions are also thorough and include helpful information like torque specs. It also has a high-visibility LED.

The SureSwitch has sealed contacts, so insects can't get to the contact points and cause pitting or failure to close. There is also a latching relay feature, which prevents chattering at lower voltages; the points stay fully closed. The SureSwitch also has a microprocessor that monitors the electrical current going inside the relay. If that microprocessor detects arcing, it knows that the contact points had closed somewhere close to the peak of the arc, and it will adjust itself accordingly.

The SureSwitch now has a multi-volt coil, so it can work in residential AND commercial HVAC. Instead of being limited to single-phase 240v applications, we can now apply that contactor to three-phase and 208v applications.

Jim and Bryan also discuss:

Shunts
Contactor chattering
Opening or closing at the zero point of the sine wave
Mounting points
Why insects like to get into contactors
Contact configuration
Time delays
Maintenance contracts and customer loyalty incentives
Short cycling for testing purposes

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Don't Miss The Tech Training Event Feb 23, 2021

Other Uses for Nitrogen - Short 113 Feb 23, 2021

In this episode, Bryan and Craig Migliaccio (AC Service Tech) discuss all the ways that nitrogen can make your job easier.

Nitrogen is an inert gas that we can use for purging refrigerant lines and completing scale-free brazing jobs. As techs, we should have at least one inert gas in our trucks to help us do the best job possible. We can use inert gases for purging refrigerant from tubing, flowing and preventing oxidation while brazing, and pressurizing a system for leak detection or a pressure test. You'll also find nitrogen useful for getting oil out of the way before pulling a vacuum.

You can also use nitrogen to help clean out a drain line. However, you'll want to be careful; if the PVC pipe isn't secure, you could create leaks (or a total blowout). You can cause severe structural damage if you flow a compressed gas under too much pressure.

In some cases, we also use nitrogen to pressurize a gas line (including propane or natural gas lines). We can pressurize that to about 6 PSI to get the pressure up to a more desirable level. (Not to mention, we can reinflate tires with nitrogen, though that's not a strictly HVAC-related application.) Outdoor units may be installed near a dryer vent, which increases the risk of the unit getting dirty. When that's the case, you can use nitrogen to blow off any of the lint and debris.

Overall, you can use nitrogen for applications where you'd usually use compressed air. Anytime you work with any kind of inert gas, you need a flow meter and regulator; a normal gauge manifold just won't cut it. Make sure you flow the gases at appropriate pressures, too.

Check out Craig's website at acservicetech.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Is Ultrasonic Leak Detection Best? Feb 18, 2021

In this podcast episode, Bryan and Craig Migliaccio, AC Service Tech, talk about ultrasonic leak detection. They discuss its effectiveness and if it's worth the hype.

Ultrasonic leak detection works best when there's oil on the inside of the tubing; it works best when the system is equalizing after shutoff. Oil or moisture can create a squealing noise, which is an indicator of a leak. Ultimately, lack of success with ultrasonic leak detection comes down to user discomfort and a lack of proficiency. Bubbles alone won't be enough, so it's good to use an ultrasonic detector, even if you need to use a heated-diode or infrared detector as a backup if you lack confidence.

You can use nitrogen to assist with leak detection BEFORE refrigerant goes into the system; nitrogen is great because it is an inert gas. However, you must be careful with pressurization, as overpressurization may lead to leaks. You must also keep in mind that nitrogen is the dominant element in our atmosphere, so no leak detector would be able to sample nitrogen alone.

If refrigerant is in the system, we can use heated-diode leak detection with relative ease. However, heated-diode leak detectors require a lot of maintenance. In any case, sensors must be matched to the refrigerant you're looking for. Infrared detectors generally work well, but they can be confusing and lead to errors. You must usually keep moving infrared thermometers to catch a leak accurately.

Craig and Bryan also discuss:

Various types of leak detectors
Having confidence in your tools
Pressure test vs. leak detection
Using your senses first
Sensor placement
Stratus leak detector
Reading the manual
Servicing leak detectors
Leak reactant (soap bubbles) limitations
Relying on guesswork

Check out Craig's site at acservicetech.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Universal Defrost Controls w/ Jim Fultz Feb 17, 2021

In this podcast episode, Jim Fultz with White-Rodgers joins us to discuss universal defrost controls. He also explains when and why you might use universal controls. Bryan and Jim cover a universal defrost control for heat pumps (Model #: 47D01U-843). You can follow along by reading the manual HERE.

Universal defrost controls can replace OEM defrost controls. Universal controls are sometimes more readily available than OEM parts, so they can be good repair options. The White-Rodgers universal heat pump defrost control comes with the board, installation instructions, two wiring harnesses, two thermistor-style sensors, and a bag with screws, wire nuts, and other mounting materials. This particular control is compatible with 400 different product SKU numbers, so it's a versatile replacement.

The display of the White-Rodgers universal heat pump defrost control gives a lot of feedback; it has orientation options and can communicate more information than mere flashing LEDs. You'll have to set the display orientation in an ideal position, but the controls will help you out with that.

You'll also want to keep these defrost controls out of the sun, away from snow, and on the back of the unit. If you don't already have an outdoor coil temperature sensor set up, then you'll want to install the sensor at the bottom of the condensing unit coil.

As far as the actual defrost options go, you can set seven different options that correspond to specific manufacturers' controls (OEM Quick Setup). The short cycle time, reversing valve, time delay, and maximum defrost times can be tailored to each manufacturer's equipment.

Jim and Bryan also discuss:

Spade connections
Wiring diagrams for the universal defrost control
Outdoor thermostat and electric heat
Oil behavior
Demand defrost
Annual energy savings
Table settings
Reversing valve shift delay time
Auxiliary heat
Low-temperature compressor cutout
Brownout protection
Force-initiation

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Maybe Don't Buy New Tools - Short 112 Feb 16, 2021

In this short podcast episode, Bryan and Craig Migliaccio discuss why you maybe don't want to buy new tools.

Whenever you get new tools, you have to account for a learning curve and potential change to your practices. Changing your practices and procedures isn't necessarily a bad thing, but you have to practice with the tool and account for different setup and cleanup procedures. However, once you find a good process, you don't want to mess with it too much. You will also want to account for changes to your tool maintenance procedures.

When you go from analog to digital tools, you want to make sure you understand exactly what you're measuring. So, Craig recommends spending time with compound gauge sets and to understand how to find superheat and subcooling before you start using digital gauges. It's best to have some good tactile experience troubleshooting a system with analog gauges. Probes have several advantages, including their Bluetooth compatibility, reduction in refrigerant losses, eliminated risk of contamination, and accuracy. However, without a solid foundation in troubleshooting, switching to probes may make you a bit inefficient.

Calibration is another factor to consider with new tools. You must know how (and when) to calibrate your tools. Calibration is part of maintenance, and it's something you need to account for whenever you purchase a new tool and learn how to use and take care of it.

Whenever you get a new tool, remember that you want consistency, efficiency, and positive outcomes for customers.

Craig and Bryan also discuss:

Pulling cores
Evacuation and recovery
Accuracy of sensor technologies
Finding the tools that work for YOU
Muscle memory with tools
Ideal applications

Check out Craig's work at acservicetech.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How Craig Became "AC Service Tech" Feb 11, 2021

In this podcast episode, we find out how Craig Migliaccio became "AC Service Tech." He makes educational materials and has even written a book. You can check out his website HERE and his YouTube channel, AC Service Tech, HERE.

Craig got into the HVAC trade after coming from a construction background; he mostly worked on existing homes and had to handle some HVAC tasks. From there, he got into service and went headfirst into the HVAC industry by starting his own business: a carpentry and HVAC business.

Craig also got into the teaching side of the trade, starting off by becoming a maintenance supervisor at a school. As a teacher, he emphasized the importance of basic mechanical skills when he taught high schoolers and young adults. He also noticed that a lot of people were interested in the HVAC industry, so that's what he focused on as a teacher. Craig started making his own videos to introduce students to a topic, and that's where his story as AC Service Tech began.

In the classroom, Craig drew from many different resources. So, he decided to continue adding to his knowledge. He eventually compiled his knowledge and began making his own resources. As a content creator, Craig is more independent and less of a collaborator, but he still manages to have an impact on others. He has also published a book (Refrigerant Charging and Service Procedures for Air Conditioning) and a workbook, which are valuable teaching and learning tools.

Bryan and Craig also discuss:

Obtaining knowledge and building skills
Figuring out what you don't know as an instructor
Sequence of instruction
Making an impact as a writer and instructor
Community vs. substance in content creation
Using your knowledge to help others
Craig's available educational resources

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

What Skills and Knowledge Should You Start With? - Short 111 Feb 09, 2021

In this short podcast episode, Bryan and Craig Migliaccio discuss the skills and knowledge you should have to start in the HVAC industry.

Of course, basic mechanical skills and knowledge are important before you get into the HVAC trade. You'll greatly benefit from knowing where and how to hammer nails, tighten screws, and identify all sorts of tools. When getting into the HVAC industry, one of the low-hanging fruits that you need to consider is your sheet metal skills. Know how to cut sheet metal, use shears, use a duct knife, and make a decent sheet metal job. Take shop classes, work on cars, and get more experience to work on your mechanical skills and tool knowledge.

A basic sense of maturity is also crucial for getting into the HVAC industry. You have to be able to work hard and feel some sort of satisfaction from working hard. The HVAC trade is also full of self-starters, so it's best that you're a self-starter when it comes to basic life skills.

The location where you will work in HVAC is also relevant. Make sure you have regional knowledge of building design and HVAC infrastructure (duct design, system types, joist orientation, etc.). Take an interest in local homes; look for supply and return registers. Know the HVAC equipment you will be working on and where it will be located in many buildings. It's also good to research terminology and know what you're talking about before you begin applying for HVAC technician/installer jobs.

Craig and Bryan also discuss:

The problem of the word "should"
Using saws and drills
Solving everyday mechanical problems
Sensing maturity
Researching companies before you apply
Watching videos and reading books
Work ethic and desire to learn

Buy Craig's book HERE and his YouTube channel HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Controlling Liquid Refrigerant in A/C Feb 04, 2021

In this podcast episode, Bryan and Trevor Matthews of Emerson Canada discuss strategies for controlling liquid refrigerant in A/C and refrigeration systems. They also read through the AE22-1182 bulletin, which you can find HERE.

Liquid refrigerant is one of the most common causes of compressor damage and even failure. It can also cause a loss of oil, which leads to reduced lubrication and subsequent damage. Compressors are vapor pumps, and they are not designed to handle much liquid refrigerant at all.

Off-cycle refrigerant migration is one of the main causes of liquid refrigerant reaching the compressor. Controlling liquid refrigerant in the off cycle is important because oil can also saturate that liquid refrigerant inside that compressor. That can cause a severe problem when the compressor starts up again. However, crankcase heaters can keep refrigerant migration at bay, as the refrigerant will be less likely to migrate and condense inside the compressor.

Liquid line solenoid valves and pump down cycles prevent refrigerant from going into the evaporator during the off cycle. During a pump down cycle, the compressor pumps all the liquid refrigerant into the condenser and receiver. If anything leaks past the solenoid, the compressor keeps pumping the liquid out. It's also best practice to use a crankcase heater if you use a one-time pump down.

Trevor and Bryan also discuss:

How to navigate Copeland bulletins
Oil miscibility with refrigerant vapor
Oil viscosity and its effect on oil return
Tripping oil pressure safeties
Crankshafts and bearing wear
Slugging vs. flood back
Minimizing refrigerant charge
Continuous vs. one-time pump down
Compressor temperature and its effect on liquid refrigerant control
Accumulators
Overheating or carbonizing oil with crankcase heaters
Oil separators

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

TXV Power Element / Power Head - Short 110 Feb 02, 2021

In this short podcast episode, Bryan talks about the TXV power element or power head. He explains what it does and why it's important.

A TXV power element threads onto the top of the valve, and it's where the sensing bulb attaches to the valve. It is the component that applies the opening force to the TXV.

When you lose the charge in the element, it stops exerting an opening force on the valve. So, the valve completely shuts and doesn't allow refrigerant to get to the evaporator coil. You'll get high superheat and a starved evaporator.

Whenever you're checking one of those elements, it would be wise to check for a leak. The capillary tube that goes between the bulb and the element is usually easy to diagnose. You can usually see cracks, leaks, or rubouts quite easily. (If you're used to working with TXVs, you may even be able to hear or feel when the bulb is light on charge.) Because the element threads to the valve, it is usually quite easy to replace without condemning the entire TXV.

If you're not sure that the TXV power element is the issue, you'll want to turn the superheat adjustment nut to the fully counterclockwise position (fully open). Once you do that, verify that the superheat is still too high. Then, remove the bulb from the suction line and warm it up in your hand for a little while. If the element still has charge, you'll notice more opening force on the valve. If the valve doesn't change at all, then the power element is the most likely problem. You should also not be able to depress the TXV's diaphragm with your thumb; if you can depress the diaphragm, then the element has lost its charge.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Value Engineer Better w/ Alex Meaney Jan 28, 2021

In this episode, Bryan and Alex Meaney talk about value engineering. They discuss what it means to value engineer better when it comes to construction projects.

Value engineering is about finding ways to reduce the costs of a project. However, we don't want to do a bad job or use extremely cheap materials just to bring the price tag down. In many cases, builders will want to reduce the cost as much as possible, but we also want to make sure the construction project works in the end. In other words, 2+2 doesn't quite have to equal 4, but we don't want it to equal 3. We can't afford to lose work or do bad work.

When we value engineer, we have to bring some sales experience to the table. We will have to negotiate with builders, and the process of value engineering is transactional. We also have to be honest about solutions that will work and ones that won't. It's best to show builders previous value engineering solutions that have failed. You don't have to sound robotic in your meetings with builders, but you want to be sincere and have a consultation process that works for you. It's a good idea to let previous results speak for themselves.

However, you will want to mention options that you think the builder will reject. More often than you could imagine, the builders do indeed take those more expensive add-ons.

Alex and Bryan also discuss:

Speaking your customer's language
Coming to the table with the most expensive option
Selling vs. consulting
Printing your failures
Approaching a sales conversation with pros and cons
Changing solutions and technologies
Finding a consultation process that works
Price objections about parts warranties
New constructions vs. retrofits
Where builders usually want to cut costs
Flex duct

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

TXV Bulb Placement - Short 109 Jan 26, 2021

In this short podcast episode, Bryan talks about the placement of the TXV sensing bulb. He also explains how it affects the opening force on the TXV.

The TXV sensing bulb (or sensor on an EEV) provides the opening force for the valve. The warmer the bulb gets, the more the valve opens; the colder the bulb gets, the more the valve closes. The TXV also has a closing force provided by the spring pressure and equalizer (usually the external equalizer).

So, if you have a bulb that has been poorly mounted or insulated, you tend to have more opening force than the design. Your suction line will generally be colder than the airstream around the evaporator coil. If the sensing bulb has poor contact with the suction line, it will likely read warmer temperatures than it should.

When the TXV opens more than it should, the valve loses control and could lead to flooded conditions. (If that liquid gets to the compressor, then you could get catastrophic damage.) Generally speaking, improper TXV bulb placement will result in low superheat and potential flooding. When you have a high superheat or a starved evaporator, the sensing bulb placement is rarely the actual problem.

When mounting a sensing bulb, the suction line should be clean. Get rid of all Armaflex residue and ensure that the bulb is also clean. In some cases, you may need to insulate the bulb. You must also ensure that you mount the sensing bulb securely near the evaporator outlet, and you can be a few inches downstream of the external equalizer. Another common suggestion is to place the bulb on top of the line if the line is smaller than 7/8" (larger than 7/8", you can mount the bulb at 4 o'clock or 5 o'clock on the line).

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Dealing with Difficult Customers Jan 21, 2021

In this podcast episode, Bryan, Erich Vinson, and Anthony Marino talk about dealing with difficult customers in the HVAC industry.

When working with customers in general, it is best to make eye contact with the customer, listen to them, and put yourself in their shoes.

When dealing with difficult customers, we must remember that there are several potential causes for their "difficulty." You can't control that; you just have to let the anger run its course and diffuse the situation as much as possible. Some customers also try to stir up drama; in those cases, it is best to focus on the mission and stick to fixing the problem at hand to avoid adding negativity to the situation. Instead, we want to focus on communicating the appropriate information while avoiding overcommunication.

Being thoughtful is the key to good customer service. So, follow-up is especially important because it shows that we care about the customer show attention to detail, and have been deliberate in our service. Commercial managers and owners also care about their bottom line. So, we need to be attentive to their business-related concerns.

Price objections are common among difficult customers. You'll want to put yourself in the customer's shoes and give them the choice to order a cheaper part. You can use that situation to explain the value of your labor. If you keep your body language under control, you can handle those difficult conversations well.

Erich, Anthony, and Bryan also discuss:

Residential vs. commercial HVAC customer experiences
Managing our own emotions before we approach customers
Being dragged into corporate or landlord drama
Being deliberate
Where price objections come from
What makes residential and commercial customers upset
Dealing with disrespect

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Hydrostatic Pressure - Short 108 Jan 19, 2021

In this short podcast episode, Bryan explains how hydrostatic pressure can build up in refrigerant cylinders and present a hazard to technicians.

Your refrigerant cylinders have tare weight and water capacity values stamped on the tank. You'll want to use these when weighing the refrigerant you recover because you don't want to exceed 80% capacity. However, capacity changes when the liquid density changes; that density will change with pressure and temperature.

Hydrostatic pressure builds up when you have overfilled refrigerant vessels. When those vessels get warm, the density will decrease, and the liquid refrigerant expands. At some point, the vessel will contain 100% liquid and can no longer expand, so hydrostatic pressure will build. When that happens, you have a dangerous situation on your hands; the vessel may even explode.

AHRI recommends using 77 degrees as a guideline for figuring out the vessel capacity. However, we recommend using 130 degrees out of an abundance of caution; the back of your van probably won't get much hotter than that, so we use it as an operational maximum.

We only get hydrostatic pressure when we recover refrigerant as a full liquid. When we recover refrigerants like R-410A in the liquid phase, we get a 45-PSI increase for each degree (Fahrenheit) of temperature increase. For R-22, that number is about 60 PSI; with R-134A, that number is about 40 PSI. When we get temperature swings from an ice bucket (~32 degrees) to the back of a hot van (~130 degrees), the pressure can build up within the vessel.

We also need to think about hydrostatic pressure when pumping down systems with microchannel coils. Hydrostatic pressure can build up in the receiver, and liquid can fill your condenser.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Introduction to Industrial Refrigeration Jan 14, 2021

In this podcast episode, Bryan, Trevor Matthews, and Jim Dick from Emerson give us all an introduction to industrial refrigeration. Jim works with contractors to provide tech support. He also does the startup and commissioning of refrigeration compressors and gas compression units.

Industrial refrigeration refers to warehouses and distribution networks. Grocery refrigeration is commercial refrigeration for the end-user, but industrial refrigeration is commercial refrigeration for the distribution network before the product reaches the end-user. Many of these large systems use natural refrigerants (including ammonia) and are easier to work on because of their scale and easy-to-access valves. However, the ammonia charge is small and is almost never in the same space as people, and industrial equipment often uses a brine fluid for heat transfer.

If techs want to move into industrial refrigeration, Jim recommends attending seminars on ammonia and natural refrigeration. Trevor believes that trade schools are currently lacking industrial refrigeration programs, and he hopes to see that change in the future.

Most people who succeed in the industrial side of the business are good electrical troubleshooters. When working on large equipment, you will have many electrical sensors and controls. The piping side is usually easier to learn than the electrical side, so some electrical proficiency is desirable. Many techs struggle with electrical concepts, so we encourage going back to the basics; do whatever you need to do to get a solid foundation. There are also many electrical contractors who would love to teach people who struggle with electrical concepts. However, learning about electricity also requires commitment and honesty about when you're in over your head.

Bryan, Trevor, and Jim also discuss:

Emerson's Vilter brand
Ammonia-CO2 cascade systems
Propane refrigerant
Gaps in industrial education
Building electrical troubleshooting skills
Manufacturer-contractor relationships and dealership networks

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Prevent Refrigerant Migration - Short 107 Jan 12, 2021

In this short podcast episode, Bryan talks about the strategies we can use to prevent refrigerant migration during the off cycle.

We often see refrigerant migration when the compressor is lower than the evaporator, especially in low-ambient conditions when the refrigerant can condense in the crankcase. When the compressor starts up, you get a violent reaction as the refrigerant boils off and ejects oil. That can wear out the compressor and reduce the lubrication.

Crankcase heaters are some of the most common devices we use when preventing refrigerant migration. These can be of the insertion or belly-band variety. As their name suggests, crankcase heaters keep the crankcase warm during the off cycle to prevent the refrigerant from condensing. However, that isn't a complete solution for stopping flooded starts and other issues.

In the cases of flooded starts, we can use liquid line solenoid valves. These valves close off the liquid line when de-energized (in the off cycle). In many cases, we can use these WITH a crankcase heater for more protection.

We also use pump down solenoids to prevent refrigerant migration. In these cases, the liquid line solenoids will de-energize while the compressor and condenser fan keep running. Then, the system cycles off on a low-pressure switch. If there is any leakage in the valves, the compressor can short-cycle. You can prevent short cycling if you have a pump-out control. However, it is usually a good idea to use a pump down solenoid with a crankcase heater.

We also use hard shutoff (HSO) or non-bleed TXVs in residential HVAC. These function a bit like a liquid line solenoid valve, but you'll also want to use a crankcase heater for added protection.

Learn more about Refrigeration Technologies HERE.

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Weird Transformer Talk Jan 07, 2021

In this podcast episode, Eric Mele joins Bryan for some weird transformer talk. They discuss corner-tapped transformers and some thought experiments.

We hadn't been able to get our heads around corner-grounded transformers until recently. "Grounding" doesn't necessarily change the phase or lead that you ground. If you take the secondary of a 24-volt transformer and measure from your two colors, you'll measure 24v. However, if you connect a lead to ground, you'll still read 24v. (Don't ground both, or you'll get a short.) Ground is just a path back to the power source. Electrons don't suddenly "leak" from something connected to ground.

Grounded and neutral conductors can potentially be dangerous. There can still be potential even though your leads wouldn't pick it up. In residential HVAC, we're used to seeing neutral and ground connected at the main distribution panel. However, it's not always okay to connect ground and neutral or use ground as a current-carrying conductor.

If you've got split-phase power going into a regular home, you've got 120 volts 180 degrees out of phase with each other. If we don't have a center-tap neutral, it would function similarly to a 24v transformer. In that case, it's not necessarily unsafe to read 0v on neutral. We get tripped up because we think in terms of using a meter, not in terms of actual potential voltage.

In a delta configuration, you will have a high leg connecting to neutral (B phase is usually high; A and C phases are usually normal). You can't really center-tap a delta, so you have to tap the center of one phase.

Eric and Bryan also discuss:

Working out of a truck vs. a van
Shunting high-voltage spikes to ground
Center-tapped transformers and "wild legs"
Ground is NOT necessarily the earth
Hot legs on the primary AND secondary

Learn more about Refrigeration Technologies HERE.

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Internal vs. Externally Equalized Valves - Short 106 Jan 05, 2021

In this short podcast episode, Bryan compares internal and externally equalized valves. He also covers how forces act upon the TXV.

Equalization does not happen on the off cycle. When we talk about equalization, we are merely talking about a force that balances against the bulb force. A TXV sets the superheat within an operating range at the evaporator outlet; the sensing bulb on the TXV detects temperature and pressure at the evaporator outlet. So, those readings apply an opening force to the bulb. (Think of this process as being quite similar to you measuring the superheat and suction pressure.)

The equalizing force is a closing force. When the closing force is applied to the TXV, it balances against the opening force provided by the sensing bulb. So, we have two ways of providing the closing force: within the valve at the evaporator inlet (internal) or externally.

In an internally equalized TXV, the closing force that equalizes the bulb's opening pressure is taken at the evaporator inlet. The measurement is internal to the valve at the evaporator inlet. However, in externally equalized valves, the closing force comes from the evaporator outlet, which is beyond the valve. Externally equalized valves work best on systems with significant pressure drops within the evaporator coil or on systems with distributors. If we were to use internally equalized TXVs in those cases, it would be like measuring superheat at the wrong location.

If you don't have a significant pressure drop, then you can use an internally equalized valve. These systems will usually be small (less than one ton) and won't have distributors. Most of the time, we will see externally equalized TXVs; these will ideally take readings within six inches of the bulb.

Learn more about Refrigeration Technologies HERE.

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Custom Performance Home w/ Spohn Dec 31, 2020

In this podcast episode, Bryan talks with Bill Spohn about his most recent project, SpohnHome. SpohnHome explores Bill's journey in custom home performance.

Projects are complicated because so many trades work together to accomplish a building. However, custom homes are particularly challenging, especially in Bill Spohn's case. His home is a "personalized performance home," so he's prioritizing energy efficiency, indoor air quality, and comfort as well as aesthetics. The home's design and purpose resemble that of a passive building.

Although much of the construction went smoothly, there was a misunderstanding about the sewer conditions; unbeknownst to the township, a nearby property had a private sewer installed, so Bill could no longer tie the plumbing into the existing sewer system. That development put a monkey wrench in the plans, and Bill's team had to come up with new ideas for a septic system (and had to follow a bunch of rules). Even though a project may seem to have a perfect plan, setbacks can still occur due to miscommunication or unfortunate events (such as the death of someone integral to the project, as Bill experienced).

Bill also used an air-source heat pump with zones for his HVAC system. He had to experiment with his home's ventilation to strike the ideal hybrid solution, as IAQ and efficiency were very important to him on this project.

Custom constructions also have plenty of room for the team to do some unconventional things, including making 3D models of the home that gives accurate volume measurements.

Bryan and Bill also discuss:

Customer follow-up
Modular building
Plumbing conditions
Divining and drilling wells
Fresh air and filtration solutions
Air sealing and blower door testing
Dealing with snow
Humidity considerations
TruTech Tools news

You can find out the details of Bill's home construction at spohnhome.com.

Learn more about Refrigeration Technologies HERE.

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Service Valve Tips - Short 105 Dec 29, 2020

In this short podcast episode, Bryan talks about some tips you can use when working with a multi-position service valve.

A service valve will have a line connection, which connects the valve to your line set. You also have a gauge port that you can connect to, a valve stem, and a packing gland nut (directly beneath the valve stem).

If your stem is completely back-seated, then your gauge port is completely closed from both the line and system connection. If you crack the stem off the back seat, then the gauge, line, and system can all communicate. Completely front-seating the valve will generally close off the line connection, but it may also close off to the system connection on some valves. Mid-seating puts the valve stem right in the center for maximum flow.

If you're working with a service valve in a grocery refrigeration application or old A/C system, you may be tempted to use any old wrench on the valve and can damage the valve. So, whenever you work with one of these valves, make sure you use a refrigeration service wrench only. Also, be sure to exercise caution.

The packing gland nut helps keep everything together and prevents leaks. However, you need to loosen it by a quarter to full turn before opening the valve. If you don't loosen the packing gland nut, you will have a hard time adjusting the valve, and you may even damage it.

Whenever you do any brazing on or near a service valve, be sure to protect it from the heat (such as with Refrigeration Technologies WetRag). You'll also want to mid-seat the valve before you start flowing nitrogen.

Learn more about Refrigeration Technologies HERE.

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Refrigeration Scroll Compressors Dec 24, 2020

In this podcast episode, Bryan and Trevor Matthews from Emerson talk through scroll compressors in commercial refrigeration equipment.

Scroll compressors are not a monolith; although they all function similarly, they have different fine details and manufacturing protocols by application. Low-temp, medium-temp, high-temp, and A/C scroll compressors each have unique designs, operating conditions, and service considerations.

Copeland has a medium-temp scroll compressor line (ZB and ZS) for medium and high-temp applications. They also have a low-temp line (ZF). Within those lines, there are also small displacement and large displacement compressors, advanced scroll temperature protection devices, and other unique features.

Since scroll compressors are prone to thermal overload, some Copeland compressors have advanced scroll temperature protection devices. These devices help redirect the discharge gas to the suction gas, which gets the compressor to trip out on thermal overload more quickly. In cases when you're tempted to condemn the compressor, shut it off and let it cool down before you jump to conclusions.

The compression ratio is the main difference between A/C and refrigeration scroll compressors. A/C scrolls can handle a compression ratio of 11:1. Conversely, refrigeration scrolls can handle 26:1 compression ratios.

Copeland scroll compressors also have electronic controls. When setting up these controls, you need to keep the scroll compressor type and special features in mind, including temperature protection devices. In other words, you can't set up a low-temp compressor the same as a medium-temp and so on.

Bryan and Trevor also discuss:

Differences across Copeland scroll compressors
Low-temp vs. medium-temp vs. high-temp refrigeration
Copeland compressor nomenclature
Compressor pump down
Proper vacuum
CoreSense diagnostics
Vapor injection and compressor capacity
PTC (positive temperature coefficient) thermistors
Using AE bulletins as tools
Crankcase heaters and other accessories

Learn more about Refrigeration Technologies HERE.

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Bert's Top Soft Skills Tips Dec 17, 2020

In this episode, Bryan and Bert talk about soft skills. They also discuss why soft skills are important in highly technical trades.

Bert's class defined "soft skills" as communication skills; these can be verbal but may also include body language and how we respond to emotional situations. Bert thinks these skills are some of the most important skills you can develop in the HVAC industry and in life overall. You will only be able to make the most of your talents and career if you work on your communication and people skills.

You can start improving your soft skills when you learn to see yourself accurately. Are you introverted or extroverted? Have a Type A or Type B personality? Once you can see your strengths and weaknesses, you can learn where you need to be more engaged with the customer or give them some space. You can analyze your relationships to see where your strengths and weaknesses are (or if you're the problem in your interactions with others).

Listening skills are also crucial for interactions with customers. Being a good listener, keeping your emotions in check, and proposing solutions will give your customers a better experience. Having the discipline to be a good listener will also help your work and personal relationships. If you need some tips or have some questions about your general vibe, ask people who want to tell you the truth about their "experience" with you (and listen to them).

Body language is also critical. Do your best to show that you're attentive, helpful, and friendly.

Bert and Bryan also discuss:

Residential vs. commercial interpersonal skills
Skills vs. natural abilities
Metacognition
Customer experience
Discipline
Working well with your bosses or other employees
Eye contact
Complaining (just don't do it)
Dos and don'ts of showing empathy

Learn more about Refrigeration Technologies HERE.

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Gas Furnace Diagnosis & Inspection w/ Jim Bergmann Dec 10, 2020

In this podcast episode, Bryan and Jim Bergmann talk about gas furnace diagnosis and inspection. They cover the ins and outs of furnace assessment.

A gas furnace diagnosis requires a few important measurements, but a solid visual inspection is perhaps even more vital. You'll want to look at the venting and condensate disposal systems. You'll want to make sure the flue gas can escape properly and that the terminations are correct and safe; if you're not looking at the manual and checking the venting, you can put your customers at risk of serious CO poisoning and even death.

On the condensate disposal system side, you risk trapping flue gases in the trap. Condensate can also build up into the secondary heat exchanger, which leads to a rise in CO.

We also need to look out for issues on the electrical side. Reverse polarity and poor grounds are often the greatest culprits for electrical failures. Broken connections are also common problems as with other HVAC systems. Dust and dirt can also get behind the circuit board, which can cause flame rectification problems. Fixing an electronic circuit board can intimidate some techs, but soldering a circuit board is quite a bit like soldering a coil.

When it comes to measurements, your pressures are going to be some of the most important readings you can take. It's also a wise idea to have your own combustion analyzer and make sure to take care of it over time.

Bryan and Jim also discuss:

New MeasureQuick developments
Measurements to use in MeasureQuick
CAZ testing
CO sources
90+ furnace condensate drains
Air filtration and MERV ratings
AHRI CO testing steps
Conduction through the flame rectification circuit
Incoming gas pressure
Incorporating MeasureQuick into diagnosis

Learn more about Refrigeration Technologies HERE.

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Pitot vs. Static Pressure Probe - Short 104 Dec 08, 2020

In this short podcast episode, Bryan talks about the differences between pitot tubes and static pressure probes. He also explains how each one works.

People often mix up static pressure probes and pitot tubes. A pitot tube is a tube within a tube, and a static pressure probe is just a tube with holes in the side but not at the end. When we measure static pressure, we're measuring the pressure against the duct. (Think of it as balloon pressure rather than air velocity.) We use static pressure probes to look for a differential between a probe and atmospheric pressure or between two probes. As the air travels around a static pressure probe pointing in the correct direction, its velocity force will not act on the probe. We do NOT want to measure velocity with a static pressure probe.

Pitot tubes, however, come in twos. One tube comes off the side (attach a hose to this one), and one comes off the bottom. You can use the side port of the pitot tube to measure static pressure. You also have an end port to measure total pressure, which is static pressure plus velocity pressure. When using a pitot tube, you can get the velocity pressure by subtracting the static pressure from the total pressure. You point the pitot tube into the airstream to get that measurement. However, pitot tubes will only give you accurate data if you have an accurate manometer and have ideal velocity conditions. Proper positioning and duct traverse techniques are also integral to getting accurate data.

Learn more about Refrigeration Technologies HERE.

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Balancing Evaporators in a Circuit Using the TXV Dec 03, 2020

In this podcast episode, Bryan and Nathan discuss balancing evaporators in a multi-coil circuit. They specifically focus on using the TXV to do so.

When we say "balancing evaporators" in a multi-coil circuit, we're referring to the temperature of the air leaving the system; we are worried about the air keeping the product cool in grocery refrigeration. If everything works correctly, the evaporators on a rack can have different temperatures due to different refrigerant flow rates. That's when we can turn out attention to the expansion valves, which meter the refrigerant into the evaporator and manage the refrigerant flow.

Balancing evaporators with the TXV is a controversial practice; many people insist that you should balance evaporators with the equivalent line set length only. However, it's not usually possible to repipe the entire circuit, so using the TXV is much more practical. You essentially run higher superheat on the colder cases by using the TXV to create a restriction.

When you adjust the TXV, you'll want to do so in quarter-turn increments on the highest and lowest cases and wait for the temperatures to stabilize (about 30 minutes) before making further adjustments.

Tuning on rack refrigerators is another related concept. We don't see mechanical EPRs very often anymore, so we can rely on the system to make programmatic adjustments. Once the temperature and operation are stable, you can set your superheat. Typically, balancing evaporators will be more important on systems with electronic EPRs than mechanical EPRs.

Bryan and Nathan also discuss:

Pressure drop associated with fittings
Where to take superheat
Flood back risks
Modern TXVs and EEVs
Defrost controller considerations
Discharge air differences

Learn more about Refrigeration Technologies HERE.

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Mass Flow vs. Volume Flow - Short 103 Dec 01, 2020

In this short podcast episode, Bryan discusses the difference between mass flow and volume flow when referring to HVAC equipment processes.

When you are confused as to whether you're dealing with mass or volume flow, think about the units. For example, cubic feet per minute (CFM) is a measure of volume because we're talking about cubic units. We care about the volume when we think about air mixing and velocity, but volume isn't much of an indicator of the actual cooling power.

The mass or weight of the air matters more when we think about cooling a space. There is a lot of variation in how much air weighs, which will impact the performance of HVAC equipment under given conditions. Standard air has a weight of 0.075 pounds per cubic foot, but that can vary depending on humidity, temperature, and pressure conditions.

When you think about volume flow rate, think about moving boxes of matter. As a blower operates, it moves a series of air "boxes," which is a useful way to look at air velocity.

Compressors have a fixed volume in their compression chambers, unlike blower wheels. (Blower wheels move different volumes of air based on motor staging and other conditions.) However, mass flow is NOT fixed. In a compressor, we can fill those boxes with more weight (higher mass flow). On occasion, too much mass will move at once; a hot pull down is a common scenario where we have too much mass flow. In those cases, we can use crankcase pressure regulators. A system's compression ratio also has a major effect on mass flow rate; the "boxes" might be too light to keep the compressor cool enough to operate efficiently. In the worst-case scenario, the compressor may overheat.

Learn more about Refrigeration Technologies HERE.

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Freezing Evaporator Fun Facts & Frippery Nov 26, 2020

In this episode, Bryan and Sam discuss freezing evaporator coils. They explain why frozen coils happen and how to address them.

When the coil's surface temperature drops below freezing (32 degrees), the moisture in the air that condenses on the coil can freeze to the coil. In those situations, your suction saturation will probably be in the mid to high twenties.

Generally, freezing evaporators will occur when you have less load on the evaporator. When there is less heat, the evaporator temperature will drop accordingly. The return air temperature is usually around 35 degrees, though that number can fluctuate on older equipment or on systems with dirty coils. Freeze-ups usually happen due to poor airflow or low refrigerant charge, though low refrigerant is usually less severe than airflow or compound airflow-charge problems. Conditions that cause low mass flow can lead to freeze-ups.

When you approach a frozen coil, the first thing you want to do is defrost the coil completely. Then, you will want to check airflow (filter, blower wheel, and coil cleanliness) and then refrigerant restrictions and charge. You'll especially want to make sure you check the liquid line for temperature drops and ensure its temperature is warmer than the outdoor ambient temperature. In addition, static pressure is a valuable reading for determining airflow.

Drain lines can also freeze, though it's a rare occurrence. When that happens, you do NOT want to blow out the blockage with nitrogen! You will break the drain line before any ice comes out.

Sam and Bryan also discuss:

Driving the temperature down
Low charge as a cause of freezing
Considerations for various system types
Using a scale for charging
Heat pumps in heat mode
ECM motor failures

Learn more about Refrigeration Technologies HERE.

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Drain Cleaning - More To It Than We Think Nov 19, 2020

Mike Klokus and Corey Cruz from Kalos come on the podcast to talk about drain cleaning. They discuss their tips and some best practices.

Approximately 50% of the calls in the light commercial division have to do with drains, and drain cleaning is a common PM procedure. The procedure starts off when you pull the panel off the air handler and look in the drain pan. Muck can accumulate in the pan and in the back and side channels. Pay attention to the unit orientation and the drain pitch before you even start cleaning. If you need to get underneath the channels, you can use bottle brushes.

Dedicated drains are associated with only one unit. However, communal drains have multiple units running into a single drain line and have a special set of considerations. You don't want to pour something caustic into the common drain and have it overflow on the lower levels. It's also best to know where the drain leads; you don't want chemicals to wash out into a garden. Water can also create a slippery surface and cause someone to fall.

Generally, the top 3 drain cleaning methods use a shop vacuum, compressed air, or plain water; each one has its place, but they also have drawbacks. While water is ideal for cleaning, it's not always available and practical. Shop vacs are good, but the suction is limited. Compressed air is better at unclogging than cleaning, and it can cause you to blow away piping if there's a loose pipe fitting.

Mike, Corey, and Bryan also discuss:

Condensate safeties
Using shop vacs and extensions
Weight in the drain pan
Cleaning with chemicals
Copper vs. aluminum for bacterial zoogloea
Priming the drain line
Condensate assembly cleanings in residential HVAC
Capping vents (don't do it)

Learn more about Refrigeration Technologies HERE.

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Open v Closed Refrigeration - Short 102 Nov 17, 2020

In this short podcast episode, Bryan talks about the differences between single-phase and two-phase refrigeration. This particular episode is about the fundamentals of physics, chemistry, and science in general.

When we talk about phases, we're referring to the changes in the states of matter. We typically think of the states of matter as solid, liquid, and gas. In refrigeration systems, the refrigerant usually changes from a liquid to a vapor in the evaporator and then from a vapor to a liquid in the condenser; that is an example of two-phase refrigeration. We get two-phase refrigeration anytime we're changing the state of matter in order to accomplish refrigeration.

When you change the state of matter, you transfer a lot more heat than with a single-phase system. You get more heat in and out between phases due to latent. Between a solid and a liquid, the energy that goes towards the phase change is the latent heat of fusion. Between a liquid and a gas, the energy that goes into the phase change is the latent heat of vaporization. It takes a lot more heat to condense or boil water than it does to change its temperature by one degree, so we take advantage of that capacity to absorb heat into the boiling refrigerant.

There are also forms of single-phase refrigeration, including John Gorrie's open-refrigeration machine. Gorrie's machine was just compressing and decompressing air; it was not changing the state of the air. In single-phase refrigeration, we can't make use of the extra energy from changing states. In those cases, condensers would be gas coolers.

However, when you think about it, the process of refrigerating the space is a form of single-phase refrigeration; we don't change the phase of the air. So, we merely use two-phase refrigeration to drive single-phase refrigeration.

Learn more about Refrigeration Technologies HERE.

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Changing Refrigerant Regulations w/ Bluon Nov 12, 2020

In this episode, Bryan talks with Peter Capuciati and Bryan Johnson from Bluon. They discuss how refrigerant regulations keep changing and how technicians can make sense of it.

We've begun phasing out R-22; the refrigerant can no longer be imported or manufactured in the United States. We can still recover and reclaim R-22, but the recovered refrigerant on the market can't meet the usual demand. R-22 went through a phaseout because of its ODP; R-410A has 0 ODP and was the main replacement.

However, refrigerant regulations are still changing, as R-410A will soon be ready for a phase-down due to its high GWP. There are two main replacement options for R-410A: R-454B and R-32 (A2L refrigerants). There is also R-466A, but it cuts out even earlier than R-410A on high-pressure and has worse heat transfer capabilities. Right now, R-32 is perhaps the best refrigerant (beside ammonia, which is toxic), and it's even an ingredient in the R-410A blend. However, HVAC technicians and customers alike are apprehensive about the flammability.

Although these regulations can be confusing and frustrating, the Bluon team recommends holding off from making capital decisions. While regulations are changing, it may not be a good idea to make a definitive equipment swap without knowing the final rulings. As a technician, it's good to benchmark the equipment. If you need to convert equipment, make sure to tune it to the specific refrigerant that's going in.

Peter and the Bryans also discuss:

Ozone-depleting potential (ODP) vs. global warming potential (GWP)
Equipment efficiency and its effect on GWP
R-32 and flammability risk aversion
AR5 vs. AR4
Refrigerant blends as replacements
Converting various equipment designs
Benchmarking
Bluon support and training

Check out more information about Bluon HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Single Phase v Two Phase Refrigeration - Short 101 Nov 10, 2020

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Floating Head Strategies Nov 05, 2020

CO2 Architecture Oct 29, 2020

Don Gillis joins us again to talk more about common types of CO2 systems and how they differ

Heat Pumps in Cold Climates Oct 27, 2020

In this episode, we are joined by three people who know a lot about heat pumps and cold weather. We also cover everything from the way technologies have changed, some of the pitfalls to keep away from, and why heat pumps work even in really cold climates nowadays.

Chad Gillespie: Chad is a senior manager, part of Mitsubishi Electric’s Performance Construction Team. He currently leads a national team of business development managers tasked with growing the new construction market for high-performance heat pumps. He has also worked in the construction industry for 26 years and has been with Mitsubishi Electric for 9.

Dana Fischer: Dana is a residential area manager at Mitsubishi Electric. He supports and promotes the installation of high-performance, ductless heat pumps in homes across Maine and New Hampshire. Prior to his work at Mitsubishi Electric, he was a program manager for the Efficiency Maine Trust.

Scott Libby: Scott is the owner of Royal River Heat Pumps. He has over 35 years of experience and training in the residential HVAC industry. His team sells Mitsubishi Electric exclusively; they are one of the largest heat-pump-only contractors in the country.

Heat pumps are becoming more effective and comfortable, so they are now more appealing for cold climates. Although we previously relied on gas and oil in colder climates, we have seen people using heat pumps with success in New England and even Norway. We partially have R-410A and high-speed compressors to thank for those technological advancements to heat pumps.

Chad, Dana, Scott, and Bryan also discuss:

Offsetting fossil fuel usage
Compressor advancements
Heat pump performance during the polar vortex
Leaky vs. tight buildings
Load calculations and equipment selection
Seasonal loads
Single-zone vs. multi-zone heat pumps
Design software
Flaring tools
Triple evacuation
Responsible refrigerant handling
Auxiliary heat
Mitsubishi Kumo station

Learn more about Refrigeration Technologies HERE.

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Demand Cooling + Liquid and Vapor Injection Oct 22, 2020

Trevor Matthews is back and dropping more compressor knowledge on us. This time, he talks about demand cooling and liquid and vapor injection.

In low-temperature applications, the discharge temperature would get very high and lead to oil breakdown and thermal overload, so demand cooling is a means of cooling the compressor. Demand cooling injects saturated refrigerant into the compressor body to cool it down. You're not jamming liquid into the compressor; the refrigerant flashes, which achieves a cooling effect.

A demand cooling system consists of a module, temperature probe, liquid line solenoid valve, and injection valve. On the Discus compressors, the sensor will go in the port in the compressor head. When installing these, it is important to make sure high-quality goes to the valve. It's normal to have some frost at the outlet during operation; look for frost to make sure the demand cooling system is working properly.

Scroll compressors use liquid and vapor injection almost exclusively nowadays. However, there is a difference between liquid and vapor injection for scroll compressors. A liquid injection system helps the compressor avoid high discharge temperatures (and high compression ratios). The vapor injection improves capacity and efficiency.

When troubleshooting demand cooling or liquid/vapor injection systems, you need to keep a few things in mind. For example, you need to make sure you have the right amount of tees when you retrofit a compressor with a vapor injection system. You may also have to repipe the vapor line and add a DTC (discharge temperature control valves).

Trevor and Bryan also discuss:

What happens when we change refrigerants
Return gas temperature and mass flow rate
Compressor head cooling fans
Motor operation and spinning indicators
Visual inspection
Vapor injection vs. mechanical subcooling
KVE vs. K4E
Part replacement
DTC vs. EEV w/ CoreSense diagnostics

Learn more about Refrigeration Technologies HERE.

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Intro to CO2 w/ Don Gillis Oct 15, 2020

Don Gillis with Emerson joins us on the podcast to teach us the basics of CO2 as a refrigerant. He explains how it works and its applications.

Carbon dioxide is a colorless, odorless gas that is becoming an important refrigerant for commercial refrigeration (R-744). It is desirable because it has a low critical point and high triple point, so we can use subcritical (below the critical point) and transcritical (above the critical point) CO2. Carbon dioxide also has a very low global warming potential (1), is inexpensive, and is very efficient at transferring heat.

Above the critical point, we see transcritical fluid, which is a high-pressure fluid. Below the critical point, you get lower pressures. We don't see CO2 in our everyday air conditioners because it doesn't have the typical pressure-temperature relationship above the critical point (over ~88-degree ambient conditions). It is also more common in regions with colder ambient conditions like Canada.

We rarely encounter the triple point in other refrigerants, but it is crucial in CO2 refrigeration. The triple point is the temperature and pressure at which a substance can exist as a solid, liquid, and gas. The triple point of carbon dioxide is very high, so we can come across it in normal equipment operation. We don't want dry ice in the system, so we want to charge the CO2 system with our pressure well above the triple-point pressure.

Don and Bryan also discuss:

John Gorrie's original machine
Recovery (or lack thereof)
Sublimation of dry ice (solid to vapor CO2)
Risk of asphyxiation in confined spaces
Leak detection
Saturation and operation pressures of CO2 compared to HFCs
Liquid vs. gas tanks
Piping and fittings
CO2 grades and moisture content
Sales and distribution

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Building Performance QA with Sam Myers Oct 01, 2020

Sam Myers of Retrotec joins Bryan and Kaleb on the podcast to discuss building performance. He also answers some of our listeners' questions.

Checking airflow is important for building science as well as HVAC. However, "airflow" is vague and can refer to static pressure readings (which isn't actually "airflow" at all), air from whole-home ventilation systems, or CFM per ton. We can also look at total system airflow with flow hoods. Equipment settings also matter when it comes to measuring airflow as it relates to building performance.

Leakiness (of the ducts or structure) is a common building performance issue. Blower door tests can determine the building pressurization and are a great tool for determining leakiness. However, we usually only do comprehensive "airflow," duct leakage, and building envelope tests during renovations or other large-scale projects; we don't typically check "airflow" and duct leakage when we do small repairs like capacitor replacement.

When balancing airflow, we usually rely on room-by-room load calculations. However, Sam finds that finding a pressure differential between rooms can be a bit more reliable. The main drawback is that a pressure differential won't tell you if a room isn't getting enough air, but the opposite problem is far more common and can be addressed.

The duct system's location also has a lot to do with a building's ventilation or sealing strategy. If the attic is in an unconditioned space in a humid climate, it may be best to seal the area to control the dew point.

Sam, Bryan, and Kaleb also discuss:

Airflow measurement instruments
Total system airflow
Balancing and isolating rooms with comfort issues
Grilles, diffusers, and vents in zonal duct design
Using your senses during balancing
Ventilating vs. sealing the building envelope
Infiltration and air mixing
Split-level homes
Blower doors
Building performance in commercial HVAC

Learn more about Refrigeration Technologies HERE.

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What is Correct Airflow? Sep 28, 2020

The great Ed Janowiak (Jon-Oh-Wok) joins us to talk about what correct airflow really looks like. He also explains how to design for it appropriately.

The ACCA design series (Manuals J, S, and D) all go hand in hand to design HVAC systems properly for a given space. Correct airflow will depend on how a technician or designer uses the ACCA design series. When we say "correct airflow," we mean that the CFM per ton matches the sensible and latent load for a space while maximizing comfort for building occupants. In many cases, 400 CFM per ton is the rule-of-thumb baseline for many systems, but it's not a one-size-fits-all solution. The point of the ACCA manuals is to use math to determine solutions tailored to a specific space and avoid rules of thumb.

Many technicians prefer higher airflow in the field because it leads to fewer technical problems. However, the occupied space can suffer from reduced latent removal when you have higher airflow. Variable-speed technology helps a bit to allow longer runtimes to help with dehumidification, but consumers may not be in the market to purchase those solutions.

We can use airflow grids to determine the CFM on a running system. When those grids determine that the CFM per ton is below 300, that means the equipment is likely failing to match the required sensible BTUs. Airflow also affects pressurization, which you can measure with a manometer. Overall, you will want to track airflow trends and work to optimize the airflow.

Ed and Bryan also discuss:

Using software for calculations
Friction rate
Sensible heat ratio (SHR)
Equipment selection and code compliance
Relative humidity targets
Intermittent ventilation
Ancillary dehumidification
Duct sweating
Residential vs. commercial equipment design gap
Blower door testing
Testing delivered capacity and balancing
Zonal pressure testing
Extended performance data

Learn more about Refrigeration Technologies HERE.

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Digital Compressor Facts Sep 24, 2020

Have you ever heard a compressor that keeps changing in sound as it runs? Trevor with Emerson tells us more about what that is all about and how the digital compressor operates.

Small Refrigeration Talk Sep 21, 2020

Joe and Eric join us, and we have a general conversation about small self-contained refrigeration units, including residential and commercial. Small refrigeration includes self-contained reach-ins and small walk-ins. These units typically use capillary tube metering devices.

Some of the biggest failures that occur in small refrigeration systems happen because of dirty condensers and user error (leaving doors open, etc.). You'll also want to check that the fans are working, the compressor is running, the coil is free of ice, and that the airflow isn't blocked. Inspection is the key, and gauging up is typically a last resort.

Refrigeration temperature measuring strategies can vary wildly by application. For example, open cases measure discharge air temperature. Systems with enclosed boxes (like walk-ins) typically sense return or box temperature. Small reach-in systems also typically have dial cold controls in a challenging location: buried at the end of the evaporator. There are straight and curly cold controls, but new equipment has made a shift towards electronic controls.

On small refrigeration units, we don't usually see start capacitors or hard start kits; however, we do see PTC relays and thermal overloads.

Domestic refrigerators also count as small refrigeration. They have independent controls that move air from the freezer to the refrigerator section of a normal household fridge; there is usually no cooling apparatus in the refrigerator. In systems with defrost timers, a bimetal defrost thermostat would open when the element detects no more ice on the coil, and defrost would terminate.

Joe, Eric, and Bryan also discuss:

Capillary tubes vs. other fixed-orifice metering devices
Capillary tube restrictions and R-134A
Leaky systems
Vacuum
Box temperature vs. coil temperature controllers
Set point and customer expectations
Safety controls
Resistance in circuits
Defrost fan delay and failsafe
Hoarfrost

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Single Pole Contactors & Crankcase Heaters Sep 17, 2020

Kaleb, Joe, and Eric join us again to discuss some myths about single-pole contactors. We also cover some weird crankcase heater wiring configurations.

When you have a single-pole contactor on a unit with no other resistance crankcase heater attached, the contactor energizes the compressor but is NOT a source of crankcase heat. That myth about single-pole contactors likely stems from a misunderstanding of Ohm's law and resistance heat.

We care about crankcase heat because we want to prevent refrigerant from migrating into the compressor during the off cycle. A crankcase heater keeps the compressor shell warm and prevents vapor refrigerant from condensing in the compressor. Overall, crankcase heat helps prevent flooded starts and oil loss. Some crankcase heaters can be wrapped around the outside of the crankcase, and others can be inserted into the compressor.

The crankcase heater and compressor winding can connect across an open contact to form a series circuit. (If you hook across L1 and T1 so that the other side has constant potential when the contact is open, a path can go to the crankcase heater.) The resistance in the compressor winding can contribute to the crankcase heat strategy, but Joe and Eric argue that the resistance is insignificant.

Overall, we need to remember that resistive heat is resistive heat; in a resistive circuit, your wattage is your wattage, and you can convert that directly to BTUs.

Kaleb, Joe, Eric, and Bryan also discuss:

Two-pole and three-pole contactors
Resistive heat
Operating A/C and heat pumps in low-ambient conditions
Ohming compressors
Jumpering in place of a single-pole contactor
Wire sizing
Loud thumping when the unit shuts off
Trickle current during the compressor off cycle
Power factor, reactive power, and actual power
Low-resistance circuits
Capacitor purposes, wiring, and sizing
Small charge and flood back prevention
3/8" lines

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Electronic Expansion Valves Sep 14, 2020

Trevor Matthews with Emerson Canada comes on the podcast once again to talk about electronic expansion valves (also known as EEVs). He explains how they work, what they do, and how to diagnose them.

Trevor compares electronic expansion valves to TXVs on steroids; they accomplish similar tasks, but EEVs have faster response times, better accuracy, and can improve system efficiency. The valve operates on a controller, which is the "brain" of the EEV that tells it to open or close. EEVs can come in the on-off variety (pulse-width modulation) and stepper valves, which rely on a motor to control the mass flow through the metering device. Pulse-width modulators are less accurate than stepper valves because they only have two operation settings.

When installing EEVs or systems with EEVs, in many cases, the valve will point down. When brazing in stainless steel valves, you'll usually use a 30% (or higher) silver solder. It's also a good idea to wrap the valve and flow nitrogen while brazing. The bulbs of these valves MUST be insulated and strapped properly. The bulb and transducer need to be outside the refrigerated box in low-temperature conditions.

When troubleshooting EEVs, the best thing to do is start off by reading the manual; you want to understand the valve and controller. Then, check the parameters and determine where the pressure transducer and temperature probe are located.

Trevor and Bryan also discuss:

Balance of forces and superheat control
Solenoid valves
How stepper motors control the mass flow
Various refrigerants and EEVs
Setting parameters on EEV controls
Flux and flux-coated rods
Evaporator feeding
EXD-SH and EXD-U02 controllers
Connections, cabling, and wire splices
Expansion valve hunting
Objectional current and electrical issues with controllers
Battery backup vs. solenoids

Learn more about Refrigeration Technologies HERE.

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Introduction to CoreSense Sep 10, 2020

Trevor Matthews from Emerson Canada joins us on the HVAC School podcast again to talk about CoreSense by Emerson.

Each CoreSense module has the potential to protect compressors. The technology can detect issues like overheating, short cycling, locked rotor, missing phase, low oil, and more. In short, the goal is to notify the technician or mechanic that something happened; sometimes, the control can also shut the compressor off and lock it out. Overall, it wants to communicate with the technician; different flashing codes indicate different sets of issues.

If you have CoreSense software on a laptop, you can access compressor data while the system is running. The software is available for A/C and refrigeration applications, so you can use the technology in residential HVAC as well.

Modern compressors can take a lot of abuse but last a long time. However, they can be expensive and are a total nightmare to install. Technologies like Emerson's can help technicians diagnose and fix compressors before we need to go through the financial and physical hassle of installing a new compressor. When you think about it, buying several CoreSense modules for a rack will probably cost less than a single compressor replacement. While the up-front costs may seem a bit high, Emerson packs the value into their new technology and allows customers and technicians to invest in guided troubleshooting and failure prevention.

Trevor and Bryan also discuss:

LED light flashing codes
Tying CoreSense into Emerson controllers
Scrolls vs. semi-hermetic compressors
Compressor expenses
Residential product line accessories
Zero point
Performance Alert vs. phase monitors
Application Engineering bulletins (AE8-1367 [semi-hermetic] and AE8-1424 [scroll])
Outlier diagnostics

Refrigeration Software (CoreSense Protection, Diagnostics & Performance Alert) – https://climate.emerson.com/OPI/documents/clc/CoreSense_PC_Communication_Software.exe

Air Conditioning Software (CoreSense Communications) - https://climate.emerson.com/OPI/documents/clc/CoreSense_PC_Communication_Software_AC.exe

HVACR Fault Finder App:

(Android) - https://play.google.com/store/apps/details?id=Emerson.FaultFinder&hl=en_US

(Apple) - https://apps.apple.com/ph/app/hvacr-fault-finder/id465325739

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Get The Most From Online Education Sep 03, 2020

Alex Meaney from MiTek/Wrightsoft joins us again because he’s an awesome trainer and knows a thing or two about how to more out of online education for the trades.

During the COVID-19 pandemic, we've seen a dramatic shift from in-person to online education. The transition has been hard on students and educators alike, but there are still ways to make it work.

Preparation is the key. Before you enter a class, make sure you look at the agenda and required or suggested reading. It's also a good idea to make sure you have the correct devices to access and participate in your online class; don't wait until right before the class to see if you have the right software or technology. We also recommend familiarizing yourself with the vocabulary before attending a class.

One way to boost the effectiveness of online training is to make yourself responsible for another person's learning. When you tutor or teach others, you raise the stakes of your own education. It's also good to take a class with a buddy, as you can fill the gaps in each other's learning.

The learning environment is also important; put away all your distractions, have a clean work area, and close the door to get the most out of your online class. On that same note, make sure you're comfortable; have a snack and a drink during your online training. If you need to keep your hands busy, find a quiet way to get your hands moving; we suggest writing notes down with a pencil.

Alex and Bryan also discuss:

Wrightsoft education changes
Preparation tips for instructors
Education as an investment
Ineffectiveness of PowerPoint slides
Accountability in education
Forcing yourself to have the space to learn
Time management
Asking questions
Watching recorded material
Microphone and camera awareness

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Preventing and Troubleshooting Compressor Issues Aug 27, 2020

Our good friend Trevor Matthews from Emerson Canada joins us to talk about compressors, mostly preventing compressor failure and troubleshooting issues.

Whenever we're installing or servicing a compressor, we need to think about possible systemic issues right off the bat. The compressor is the heart of the system, but everything else in the system affects how the compressor runs. You'll want to know which type of compressor you're working with as well as the manufacturer. As always, you'll want to check the superheat, subcooling, amps, TD across the condenser, and (especially) discharge line temperature.

The compression ratio is also a telling sign of the system and compressor's health. You take the compression ratio by dividing the absolute suction pressure into the absolute discharge pressure. However, we must also consider the compressor's application; by design, refrigeration compressors can deal with higher head pressures than A/C compressors.

Anytime a compressor fails, you'll want to investigate why it failed. You can only see what happened inside a compressor if you cut it open and inspect it. During the inspection, look for signs of overheating and damaged components. Whether a burnout, flooded start, or thermal overload caused the failure, you will be able to see clues about the failure and can piece together the compressor's story. Once we finish troubleshooting and diagnosing a compressor, we can focus on preventing future compressor failure. We'll have a better idea of the operating conditions we need to avoid.

Trevor and Bryan also discuss:

Head pressure (discharge pressure vs. liquid line pressure)
Compressor types
Compressor overheating
Return gas temperature
Burnout
Line driers
The 80/20 rule
Flooded starts
Short cycling
Non-bleed TXVs
Recovery and evacuation
Thermal limit
Advanced temperature scroll protector (ATSP)

Emerson Flow Chart - https://www.hvacrschool.com/wp-content/uploads/2020/08/2004ECT-126_NOTRUNNING.pdf

Compressor Installation Guide -

https://hvacrschool.com/wp-content/uploads/2018/01/Compressor-Installation.pdf

Emerson System Cleanup Bulletin -

https://climate.emerson.com/CPID/GRAPHICS/Types/AEB/ae1105.pdf

Learn more about Refrigeration Technologies HERE.

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Suction Line Temperature - Short #100 Aug 25, 2020

In this short podcast episode, Bryan discusses the importance of suction line temperature and what it can tell you about an HVAC system.

There are two main places to take your suction temperature: at the evaporator outlet and right where the suction line goes into the condensing unit. When the former number is high, you could have a starved/underfed evaporator. When the latter number is high, you may have poor suction line insulation. If the refrigerant is too hot when it goes into the compressor, you can overheat the compressor over time.

Under normal operating conditions, you will see about a 10-degree swing. At a 75-degree indoor temperature, the evaporator temperature will probably have around a 35-degree TD. So, you run around a 40-degree evaporator coil under 75-degree indoor conditions. (That is true of all refrigerants.) If the refrigerant picks up 10 degrees of superheat in the evaporator, you'll have about a 50-degree suction line at the evaporator coil outlet (+/- 5 degrees or so). Then, when you measure the suction line before the compressor, the temperature can increase about 3-5 degrees more. Overall, you'll want your temperature to be below 65 degrees at the compressor inlet.

If you see a lower temperature, then you'll want to start looking at airflow. If you see a warmer suction line temperature, you'll want to make sure the suction line is insulated, that there are no restrictions, and that the system is not undercharged with refrigerant. We are fans of non-invasive testing; that way, you can measure the temperatures without hooking up gauges and getting the pressures. Measuring pressures is not always necessary, but we highly recommend checking the suction line temperature whenever possible to benchmark the system.

Learn more about Refrigeration Technologies HERE.

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Duct Installation Best Practices Aug 20, 2020

In this podcast episode, Neil Comparetto from Comparetto Comfort Solutions joins Bryan and Kaleb to discuss some duct installation best practices he has learned. You might be able to take away some of his duct installation tips and apply them in the field.

Neil used to focus a lot on making the ducts look good, but nowadays, he focuses a lot more on performance; the work of art is in the data, not the beauty of the building materials. The quality of the seal on the duct is more important than the duct's appearance. Neil focuses a lot on leakage, and he says it all starts by committing to low-leakage connections in your mindset. He does as much sealing as he can before hanging the ducts.

Flex duct is one of Neil's favorite materials even despite its poor durability. Flex duct is quiet, well-insulated, pretty cheap, normally leak-free, and quick to install. Of course, you must install it in straight lines and pull it tight for best results, but its performance is pretty close to that of normal sheet metal.

It can be difficult to separate the install from the design, so some design features are beyond the installer's control. However, if possible, it's best to keep the duct system as small as possible. Shorter ducts reduce the likelihood of leakage and the area available for thermal transfer, especially in unconditioned spaces.

Neil, Kaleb, and Bryan also discuss:

Design and preparation before installation
Squeegee, tape, insulation, and mastic
Brands that Neil likes
Splicing flex duct
Finding friction rate and balancing
Downsizing equipment
Building codes and inspections
Balancing supply and return
Return grille placement on homes with few large returns
Getting feedback
Equivalent lengths of straight vs. 90 boots
Duct vs. register velocity
Takeoffs
Dos and Don'ts of duct installation
Filters

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Compressor Overheating - Short #99 Aug 18, 2020

In this short podcast episode, Bryan explains what happens to a compressor when it's overheating. He also covers possible causes and troubleshooting strategies.

One of the Kalos techs came across an overheating compressor case that looked like a textbook TXV problem: the superheat was high at the condensing unit on the compressor side. However, the air handler superheat was appropriate, and the suction pressure was low. TXVs, however, respond to the superheat dropping and reduce the pressure even more. Overall, the mass flow rate and velocity drop, meaning that the refrigerant temperature can increase as it spends more time in the suction line.

We were missing a few key measurements to diagnosing compressor overheating. In those cases, we want to know the return gas temperature, discharge line temperature 6 inches out from the compressor, and the compression ratio (absolute discharge pressure / absolute suction pressure). You'll generally want to see a compression ratio between 2.6 and 3 on residential HVAC equipment; the lower the compression ratio, the better the efficiency. A compression ratio higher than 3 can lead to compressor overheating. A return gas temperature consistently above 65 degrees can also make a compressor run hot. The discharge line temperature should not exceed 225 degrees.

Then, you must determine if the charge is correct. (Are you starving the evaporator?) Check if you have restrictions and if your suction line is improperly insulated. Restrictions and heat transfer in the suction line can lead to compressor overheating.

It's bad for a compressor to run hot, but they can go their entire lives without tripping on the thermal limit. Compressors that run hot can have lubrication issues and will have shorter lifespans. The best thing you can do is try to reduce the compression ratio. (Clean the condenser, keep head pressure low, keep good indoor airflow, etc.)

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Troubleshooting & Commissioning Q&A Aug 13, 2020

In this podcast episode, Kaleb, Joe, Eric, and Bryan answer some troubleshooting and commissioning questions from Facebook.

Whether we're talking about troubleshooting, commissioning, or any other HVAC/R task, the best training is on-the-job training. Meetings, educational videos, and quizzes also help to a lesser extent, but bypassing training altogether is a mistake. Senior techs can also become better diagnosticians when they teach others. "The Diagnostic Game" is an especially useful tool to help teach newbies how to troubleshoot a system.

However, training is something that is ultimately what you make of it. When you consider external training, you must consider the value of that training. (For example, NOVAR training would be useless for a residential tech but critical for a grocery refrigeration tech.) You also want to make sure your training makes you a valuable job candidate and that you stay motivated throughout training.

When it comes to diagnosis, you can't truly diagnose the equipment until you know how it operates under normal conditions. Until you become familiar with normal equipment operation, you're essentially relying on trial-and-error. Getting the answer correct is only part of the equation; you also need to know why the answer is what it is when troubleshooting.

Kaleb, Joe, Eric, and Bryan also discuss:

Leaving subcooling just shy of the target value
Balancing the charge during a hot pull down
How much can we expect techs to do training on their own time?
Just-in-time education
The relationship between training and pay raises
"Understand before you do"
Replacing parts on a unit with a failed compressor
Megohmmeters and multimeters
The Kalos residential commissioning process
Troubleshooting no-cool calls
Inspecting customers' homes
Communicating with customers
Money-losers for residential companies
Classroom training vs. field experience
Fluid dynamics in ductwork

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Advanced Fresh Air w/ CERV2 Aug 06, 2020

In this podcast episode, Ty Newell from Build Equinox comes on to discuss the CERV2 and how it embodies "advanced fresh air." The CERV2 is the second-generation version of the CERV.

A basic ERV allows for discharge air leaving the home to pass the intake air. When the airstreams cross through a core, there is an exchange of sensible and latent energy. The ERV may promote dehumidification and cooling of the incoming air. The CERV is a form of ERV technology, but it addresses the issues that may arise from crossing the airstreams. For example, we don't always want to exchange energy, so sensors can examine the air content and determine when and when not to exchange energy.

The CERV, an advanced fresh air solution, went into development in 2008, and the first unit was built in 2010. The CERV has sensors for carbon dioxide and VOCs; either one of those may dominate the air quality in the home. The CERV also uses a heat pump to exchange energy and help heat or dehumidify fresh air coming in. The CERV also has higher CFM than most ventilation solutions, meaning that it can flush out pollutants effectively. So, the CERV acts as a supplementary heating/cooling source for maximum comfort and indoor air quality.

Build Equinox is a small company, and it has about 400 CERV/CERV2 units spread throughout North America. However, because the market is small, they can examine feedback very closely.

Ty and Bryan also discuss:

Potential downsides of bringing in outside air
Dehumidification for CERV
Recirculation mode
CERV unit controls
Using hydrocarbon refrigerants
Concerns with microchannel coils
Oil carry, miscibility, and foaming
Superheat control
Assessing indoor air quality
Sensitivity to IAQ threats
Latent-dominated, sealed residential constructions
Testing and choosing sensor technology

Check out more at buildequinox.com.

Learn more about Refrigeration Technologies HERE.

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Combustion Analyzer Facts and Mistakes Jul 30, 2020

Our main man, Bill Spohn, joins us again to talk specifically about combustion. He also explains how to select and properly utilize a combustion analyzer.

It's critical to do combustion analysis when you service equipment for the first time or just after installation. We need benchmarks, so that's when our combustion analyzers can come in handy. (Of course, you also want to use your senses to inspect the equipment.) Commissioning is another good time to bust out your combustion analyzer.

Combustion analyzers should properly measure oxygen, temperature, and CO. Oxygen and temperature sensors tell you the combustion efficiency, and the CO sensor tells you about the carbon monoxide content. However, the CO sensor should also have a NOx filter to prevent nitric oxides from showing up as CO. The goal is to have no CO present in the living space, and sensors that pick up NOx can raise a false alarm.

Some combustion analyzers also have pressure sensors, which can detect static pressure drops across heat exchangers or filters. You can use these for some building-performance tests, including zonal pressure diagnostics. You can also potentially measure ambient CO with your combustion analyzer.

Once you have your combustion analyzer, you need to calibrate it and maintain it. Temperature sensors rarely need recalibration, but your CO sensor needs occasional recalibration after repeated exposure to gas. NOx filters can also expire and may need replacement.

Overall, combustion analysis is a critical part of gas furnace inspection. However, it's best to use other inspection methods too, such as looking for heat exchanger leaks.

Bill and Bryan also discuss:

Flame displacement
Condensation buildup
Nitric oxides on CO sensors
Dilution of CO and base signals
CO alarms
How CO sensors work
How air enters the home
Induced-draft systems under negative pressure in the flue

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Advice on Starting an HVAC/R Career - Short #98 Jul 28, 2020

In this short podcast, Bryan shares some of his advice for people looking to get into the trades by starting an HVAC/R career.

When you step into the HVAC/R trade, you must remember that you'll acquire a mix of skills and talents that all work together. You must reflect on yourself and see if you'll be a good fit for the trade. Do you enjoy working with your mind and your hands? Do you enjoy working to some degree? If you don't like pressure or dislike working with your mind or hands, then the HVAC/R trade isn't for you.

When starting an HVAC/R career, you don't want to rely on a system or process to provide you with everything you need. Trade schools won't provide the full scope of field education, so you can't rely on them for everything. Instead, join social media groups where professionals discuss equipment and answer questions. Watching reliable YouTube channels helps a lot, too.

Self-motivation is the key to success in this career. Don't go into an HVAC/R career if you aren't motivated to jump into new tasks or subjects. The best way you'll learn in the trade is by practicing with your own hands. Brazing and soldering are more advanced skills that your senior techs probably won't let you do on customers' equipment. However, you can read plenty of guides and practice on your own once you feel confident. You can also study for and take EPA tests on your own.

There are several points of entry to the trade: apprenticeships, trade schools, and entry-level positions with companies. The one you choose will largely depend on the availability and quality of each in your area. You want to spend a lot of time working with your hands, no matter which path you choose.

Learn more about Refrigeration Technologies HERE.

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Air Flow Hood Considerations w/ Dwyer Jul 23, 2020

Jaden Lane joins us to discuss some best practices when using an air flow hood. She also explains how the Dwyer Smart is innovating in the hood space.

An air flow hood is an excellent tool, but we can't just assume that it'll work correctly in any system. Various vents and diffusers can cause different flow patterns to reach the hood, so you can get an incorrect reading if the flow hood is not aware of the flow pattern. Unless we give the hood background on what's going on in the duct, there's no way the hood will know the correction factor to give you the correct reading for the conditions in the duct. You can adjust smart flow hoods to compensate for inaccuracy factors.

Hoods are like big canvas skirts that you place over a vent, and there's a flow grid at the bottom. As air moves through the hood, the grid takes airflow readings. There are pitot arrays that act as traverse points on a duct traverse; these arrays take multiple measurements and give you an average. These devices work better when the air is a bit turbulent. If you doubt your measurement, you can also try the hood in different 90-degree orientations (but keep it centered).

Dwyer does a lot more than just make test instruments. They have a rigorous testing process for their products; their products can also work as permanent installations within buildings, not just tools for technicians.

Jaden and Bryan also discuss:

Dwyer products, including the Magnehelic
Vent vs. grille vs. register vs. diffuser
Computational fluid dynamic analysis and other test methods
Calibration vs. zeroing
Predictive balancing
Choke and backpressure
Vane and hot-wire anemometers

Check out Dwyer at dwyer-inst.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

3D Duct Modeling For Residential Jul 16, 2020

Russ King joins us to discuss simplifying duct design for residential contractors. We focus on using 3D software for duct modeling.

While computers are great tools for duct design, you must be careful with them. Computer technology doesn't correct your mistakes; it allows you to make mistakes more quickly. Russ made 3D software specifically for duct modeling, and its goal is to help technicians/contractors with duct designs and equipment sizing. The software is good for quick duct design, can determine flex duct design, and is ideal for broad usage in residential HVAC.

Russ has noticed that existing energy modeling and load calculation software ask for extremely specific inputs, which can confuse technicians. He was frustrated with the process and wanted to make software that could help technicians solve the problems that mattered in a way that made sense. With the help of his son, Russ came up with Kwik Model (of Coded Energy). They developed software that allows users to design ducts and adjust parameters easily. The goal is for Coded Energy to be a simple, straightforward duct design software that addresses the hardest duct design issue: making the ducts fit.

Coded Energy is written in Unity, which is used for video games and architecture/automotive design. The user essentially imports a floor plan, scales it, places boxes, and stretches the boxes to meet the design conditions. Once the user has built the house, the software can calculate the surface area automatically. Then, the user can use EnergyGauge for load calculations and equipment selection. The user can then draw ducts and have the software size the ducts for them.

Russ and Bryan also discuss:

Equipment selection for latent removal capacity
Oversizing issues
Designing ducts for building plans
Comfort diagnostics
2D vs 3D modeling
Getting feedback in the field post-design

Visit kwikmodel.com to learn more.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Effectively Choose and Use Test Instruments Jul 09, 2020

Bill Spohn with TruTech Tools joins us to talk about why being “approximately correct” is better than being “exactly wrong” when it comes to test instruments.

When you see a number, that doesn't necessarily mean that you're dealing with a number you're supposed to see. For example, nitric oxide can present as "false CO" to a carbon monoxide sensor. Test instruments that mistake nitric oxide as carbon monoxide will give a different reading than ones that don't pick up nitric oxide as CO, but that doesn't necessarily make either of them wrong. So, some instruments can give you false positives based on exactly what they measure.

On the other hand, false negatives may have to do with poor sensitivity. A common case happens with leak detectors; on occasion, a leak detector won't be sensitive enough to pick up a leak.

You can't just say that a set of numbers on an instrument absolves you of responsibility for errors; you must understand the instrument, what it measures, and its sensitivity to use it appropriately. Being rigid in terms of specifications is also a mistake when communicating with customers; customer satisfaction is the goal, and it's okay if their comfort needs deviate from the specifications a bit. Overall, accommodation and mental/financial investment in your tools are the keys; for the sake of the customer, we need to make acceptable compromises, and that's something you must factor into your measurements.

Bill and Bryan also discuss:

NOx filtration
Bacharach PGM-IR
Personal protective CO detectors and overloading
Laboratory-grade instruments vs. normal test instruments
Getting valid wet-bulb readings and using sling psychrometers
Analog gauge variables and inaccuracy
Lab testing and controlled conditions
Ductwork in conditioned spaces
Flow hoods
Using our senses
Olfactory fatigue

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Going Deep on IAQ Sensors and Instruments Jul 02, 2020

Bernadette Shahin of Aeroqual joins Bryan and Kaleb as they all dig very deep into indoor air quality (IAQ) sensors and instruments. They also cover the certainty and uncertainty of measurements.

Reference method instruments generally have to operate within a set of parameters, notably a temperature range. Gas laws make the gases act differently, so you want the temperatures and pressures to stay within a range that allows you to measure the air conditions effectively.

While we can use reference methods for full-scale instruments, there are no reference methods for IAQ sensors. The only way to make something close to a reference method on IAQ sensors is to use the near reference method. We measure humidity and temperature, and we do an atmospheric chamber and calibration. You have to pair sensors within an instrument to have a product that properly senses conditions.

Measuring indoor air quality is important because we spend 90% of our time breathing indoor air with very little fresh air. Air pollutants build up in indoor spaces, and you could spend time in environments with harmful VOCs, allergens, and bacteria. Most people don't have the means of using HEPA filters or fresh air mixing in their homes; so, we need to focus on other solutions to control indoor air quality.

Those solutions include air purifiers, but they also include sensors that monitor the air quality. One such sensor is the photoionization detection (PID) VOC monitor. With sensors, we must also think about sensitivity; we want the sensor to measure what it's supposed to measure in the amounts it's supposed to measure.

Bernadette, Bryan, and Kaleb also discuss:

Barometric pressure instrument calibration
Algorithmic adjustments
Sick building syndrome
Formaldehyde off-gassing, ozone, and CO
Aeroqual's solutions for BTEX
Automatic baseline correction
R2 factor
AQI
Automating IAQ strategies
Pricing

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

VRF and VRV Piping and Installation Overview Jun 25, 2020

Jordan Cummings is back to discuss some of the most important points in the proper installation of VRF and VRV systems. We especially cover piping best practices.

When it comes to piping, the biggest concerns on VRF and VRV systems are making sure the piping can handle the refrigerant velocity and ensuring proper oil return. Most VRF systems use PVE oil, but you still want to be cognizant of oil type, as not all manufacturers use PVE. You must consider fittings, length, and elevation changes when you pipe a VRF or VRV system.

In our suction line, we want minimal pressure drop because too much suction drop reduces the mass flow rate through the compressor. You also need to think about avoiding too much of a pressure drop on the dual pressure line when it sends refrigerant to the compressor.

You want your piping to be below the connections on the outdoor unit. The piping should be pitched up towards the unit when the outdoor unit is elevated on a stand. Of course, you'll also want to be mindful of where you place the outdoor units; the units should avoid the elements and be mindful of any awnings above.

VRF/VRV systems come together at a variety of joints, including REFNETs and wyes (multi-chassis kits). Indoor units use REFNETs, which are basically engineered, balanced wyes. Outdoor units use typical wyes. Positioning these joints also makes a huge difference when it comes to proper feeding.

Jordan and Bryan also discuss:

Pipe sizing with software
Dual pressure line
PVE vs. POE oil
Miscibility and oil carry
Air-cooled vs. water-cooled condensers
Condensate drains and trapping
Reduced pumping/flow on water-cooled condensers
External static pressure
Alarms
Piping limitations
Cross piping on the branch selector box
Expansion valve staying shut
Pipe expansion
550 PSI, 24-hour pressure test
Testing as you go

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Time Management for HVAC Techs Jun 18, 2020

Bryan and Eric Mele have a relaxed conversation on time management on the job. They also explain how to manage time in life as a whole.

Some people are naturally fast because they cut corners in the name of time management. Instead, something Eric has learned to do is optimize his processes. He gets his work done a lot more quickly because he knows how to get the most out of the trips to his truck. Eric is also familiar with the tasks to perform them confidently, and he knows which diagnostic tools he'll probably need. Overall, repetition leads to efficiency.

There are also plenty of ways to streamline evacuation and recovery. For example, Eric recovered refrigerant by piercing the liquid line from the air handler. His setup consisted of two charging hoses, a line dryer, and a recovery machine; it was an economic way to save his tools and recover refrigerant in the rain.

Eric has done a lot of installs with people of varying experience levels. If there's one thing he learned, it's that you can streamline the process by starting at the outdoor unit, getting the old unit out, and getting the new unit set. The entire time, only one person should be working on the one-person jobs while the other gets supplies and makes preparations as needed. When it's time to work on the new unit, one person can work outdoors while the other works indoors.

Eric and Bryan also discuss:

Diagnostic tools to keep close or go without
Dealing with paperwork
Scavenging and saving small parts
Cleaning the drain pan
Pulling a vacuum through difficult fittings
Working with people of diverse experience levels
Using tin snips
Efficiency and payment
Work-life balance
Prioritizing parts of your life
Working with cranes

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Suction Line Traps - Short #97 Jun 16, 2020

In this short podcast episode, Bryan explains what suction line traps and inverted traps are. He also covers the purposes they serve.

It's a bit hard to find literature on suction line traps, so it's always best to read the manual and follow the manufacturer's guidelines. We traditionally use P-traps on suction lines to hold oil and let it go up the walls of the refrigerant piping. You need enough velocity to lift oil (mineral or alkylbenzene) up the riser. We know that POE carries much easier with refrigerants than mineral oil; it is very miscible with common refrigerants. That's why it's especially important to get all of the mineral oil out of retrofit systems.

In refrigeration, we have lower temperatures, pressures, and densities; that combination adversely impacts oil carry. Oil logging is a bigger concern even with POE oil. So, P-trapping with POE oil is a more common practice in refrigeration than it is in air conditioning.

In air conditioning, we can make a case for the inverted trap: in an air handler that's higher than the condenser, we want the suction line to go above the air handler and then go down into the evaporator coil. When the system goes off, there is still refrigerant in the evaporator coil, so refrigerant will condense into a liquid. We don't want that liquid to rush down the suction line and into the compressor upon startup, so we use an inverted trap to prevent flooded starts from happening. However, we can use hard shutoff TXVs and other strategies to prevent liquid refrigerant migration. Unfortunately, inverted traps can also keep mineral oil stuck in the evaporator coil.

Learn more about Refrigeration Technologies HERE.

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Preventing and Overcoming Price Objections - Short #96 Jun 09, 2020

In this short podcast episode, Bryan explains how you can prevent and overcome price objections in your HVAC business.

You can prevent price objections by avoiding the "budget" reputation. If your company establishes itself as a "budget" or "cheap" company, you will attract coupon-clipper customers. Coupon-clippers can be difficult to work with because of how cost-conscious they are. Customers who aren't looking for a deal will be less likely to object to pricing. You also don't want to shy away from money conversations with friends or family members.

Once you get your business model and clientele established, you need to overcome pricing objections in yourself. "Expensive" isn't the issue; value is. If you set a price, then you need to be confident in it; pricing is a business decision, not a moral imperative, and you won't please everybody. If you're not comfortable with the prices, your discomfort can show in your body language and turn the customer away. Another tip is never to talk down your own value or make your work seem like it should be cheap; don't be afraid to explain labor or warranty costs if the customer asks.

You can also prevent price objections by avoiding dramatic language. Instead of saying, "This will be expensive," or, "I've got bad news," you can just give the facts and the quote. If the customer gets emotional, you can empathize with them and give them a positive outlook on the situation. It also helps if you can keep money conversations as comfortable, clear, and fact-based as possible. Make sure you get customer approval and allow your customer to decline new procedures every step of the way. Bundle in extra value if you can.

Oh, and remember to be empathetic and do a good job.

Learn more about Refrigeration Technologies HERE.

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Disappearing Latent Capacity - Short #95 May 26, 2020

In this short podcast, Bryan explains why latent capacity is prone to disappearing. He also explains what actually happens when the latent capacity drops.

When you measure enthalpy split across the coil, you'll learn that the equipment design makes it perform to AHRI design conditions. Those design conditions are 95-degree outdoor temperature and 80-degree indoor temperature at 50% indoor relative humidity. So, the A/C system must remove a lot of moisture. However, we don't usually run A/C units for 80-degree indoor temperatures; we usually aim for a 75-degree indoor temperature. When we have 80 degrees, the sensible AND latent heat loads are higher. Things get tricky when we encounter disappearing latent capacity, which is when you remove less moisture.

If we have equipment with a sensible heat ratio (SHR) of 0.75 at design conditions, we'll likely have a higher SHR with our typical conditions. When the dew point is lower, water condenses on the evaporator coil at a lower temperature; water holds up the surface temperature of the evaporator coil and optimizes heat removal, suction pressure, and compression ratio. When heat transfers to the water on the coil, the sensible heat in the air decreases via a latent process.

When we don't have moisture on the coil, all of the heat going from the air into the refrigerant is making it in via conduction through the metal coil walls. Unless the coil gets below the dew point, it won't remove any moisture; we can still remove sensible heat, but you don't have the advantage of the moisture "holding up" the surface temperature.

In very dry climates, we increase the airflow because we don't want to remove moisture from the air, but we still want heat to be available to the evaporator coil. However, we have to be careful about the bypass factor.

Learn more about Refrigeration Technologies HERE.

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Demand Cooling in Low Temp R22 w/ Jeremy Smith May 21, 2020

In this podcast, Jeremy Smith joins us to discuss demand cooling in low-temperature applications that use R-22 refrigerant.

R-22 is NOT an ideal low-temperature refrigerant because it leads to high compression ratios. The discharge gas also gets really hot and can burn up the oil in the system. (The head of the compressor is even hotter than the discharge line, so if the temperature is high enough to cause oil breakdown in the discharge line, it's almost surely worse inside the compressor). However, R-22 is starting to go away in rack refrigeration.

Demand cooling injects saturated refrigerant into the compressor to help mitigate the high discharge temperature and oil damage. It may seem like demand cooling intentionally slugs the compressor. However, the saturated refrigerant should boil off almost immediately, and it should not make it to the head of the compressor under typical conditions.

On the diagnostic and repair side, demand cooling is usually pretty straightforward; if a sensor fails, then it's likely a thermistor issue. In the case of thermistor problems, you can diagnose those issues with the information given in the application engineering bulletin. Loose connections and valve restrictions can happen, but those are also pretty easy to diagnose and repair. Perhaps the most complicated issue occurs when rack systems have low liquid levels. The injector valves can't get a solid column of liquid, but many other components will work fine.

Demand cooling solutions are usually brand-specific; each manufacturer has a slightly different setup. To learn more about the Copeland Discus compressors with demand cooling, check out the AE4-1287 bulletin.

Jeremy and Bryan also discuss:

Outdoor air and head pressure
DTC valves
Desuperheaters and hot gas bypass
Tube-in-tube heat exchangers as "subcoolers"
Seasonal changes in discharge temperature
Why should we pay more attention to discharge line temperature?

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Low Voltage Electrical Basics May 14, 2020

Bryan and Kaleb cover the basics of low-voltage electrical applications. They focus on the practical stuff, not just the theory that confuses techs.

Many techs have a hard time with low-voltage electrical concepts and components because it's not easy to visualize what happens; we only see wiring diagrams, not metaphors that help us understand what's going on.

The low-voltage control circuit starts with the transformer. The transformer has a primary side (where the high voltage comes in) and a secondary side (where the lower voltage comes out). The secondary is only connected to the primary via electromagnetism; it helps to think of the secondary as an independent electrical circuit.

Color coding is a simple concept, but it has changed over the years and can confuse techs. You can only truly understand the wires by doing a complete visual inspection and tracing the wiring. (Though generally, blue will be common/C, and red will be hot/R.) We also typically use yellow for Y1, but Y is a confusing concept. Y ISN'T the compressor or cooling! Y pulls in the contactor coil; it is really the high-stage contactor. Y2 is a higher staging, and Y1 is a lower staging. On heat pumps, the white wire is usually for heating, and the orange wire is usually for the reversing valve. G is for the indoor fan and often has a green wire.

Kaleb and Bryan also discuss:

Tapping transformers
W and O calls on heat pumps
G calls
DH on 24v controls
Communicating controls
Float switch configurations and issues
Breaking Y or R with the float switch
Wire routing: air handler and condenser
Preventing conductor corrosion
NASA or lineman splice
Stranded shielded wire vs. solid wire

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Impacts of Compression Changes - Short #94 May 12, 2020

In this short podcast, Bryan talks about the impacts of compression and airflow changes. He also discusses some of the ramifications of those changes.

In order for us to energize the second stage of a compressor, we need to energize both Y1 AND Y2. On stage 2, we're running that compressor at full speed (350-450 CFM per ton). The compressor will also perform at rated capacity. When you stage down to stage 1, your blower should ramp down, and the compressor should produce less capacity (move less refrigerant). When moving less refrigerant, the compressor should use less current but still be cooled properly.

Naturally, the suction pressure goes up while the head pressure goes down when we ramp down the compressor. However, when you reduce the blower speed at the same time, your evaporator coil picks up less heat. In that case, the suction pressure would drop. You normally don't want the suction pressure to go up in the low stage from the high stage.

The impacts of compression changes are multifaceted, and there are several moving parts to think about when it comes to capacity. When the compressor slows down, it moves less refrigerant over the same period of time; your compression ratio goes down if your airflow over the evaporator coil remains the same. However, if the airflow drops proportionally, then your suction pressure should stay close to the same. If the compressor pumps the same amount of refrigerant, the suction pressure will drop. If the compressor pumps less refrigerant proportionally to the airflow, then the suction pressure should remain the same theoretically, but it usually increases.

An increase in suction pressure results in a lower compression ratio, which is good for efficiency.

Bryan also discusses:

Floating the evaporator temperature
Broken valves on reciprocating compressors
Improperly seated scrolls
Improper tonnage ratings across components
Oversized coils

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Superheat and Subcooling Basics May 07, 2020

In this podcast episode, we ONCE AGAIN talk about superheat and subcooling. This episode is a recap to help people who struggle with the concept.

You get superheat when you have 100% vapor, and you have subcooling when you have 100% liquid; any liquid-vapor mixtures are in a saturated state.

We usually measure superheat outside at the suction or vapor line. It's best to take the superheat reading as close to the port as possible. Anything in the saturated state is boiling; you can only get the mixture at the boiling point of a refrigerant. Anything above the boiling point is all vapor, and it's superheated. Very high superheat indicates that the refrigerant boiled off very early in the evaporator, meaning that the system could be low on charge. On fixed-orifice systems, you charge a system via superheat. Zero superheat indicates that you have liquid in the suction line. When you have liquid in the suction line, you can cause compressor slugging, which leads to failure.

You will usually only measure subcooling at the liquid line, usually right at the outlet of the condenser. When you read a higher level of subcooling, that means the system has more liquid stacked in the condenser. Any refrigerant below the condensing temperature is subcooled. In many heavy commercial/refrigeration equipment, you will have a sight glass instead of taking subcooling readings. Excess subcooling indicates that too much refrigerant has stacked up in the condenser, so you will likely also see an undesirable rise in head pressure.

Bryan and Kaleb also discuss:

Superman and submarine analogies
Problems with the pot of water boiling analogy
What really is steam?
Sensible vs. latent heat
Metering devices
Superheat and subcooling targets vs. measured superheat/subcooling
Adjusting charge
Condenser as a desuperheating component
Evaporative effect on the condenser

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Psychrometric Basics Apr 30, 2020

In this psychrometric basics podcast, Bryan and Kaleb talk about the properties of air. They also discuss dry-bulb, wet-bulb, dew point, and relative humidity. Psychrometrics is the study of the relationship between air and its properties.

The psychrometric chart can be a bit intimidating, but you can use it in a variety of ways. A technician should care about this chart because it helps with whole-home diagnosis. You can't see the whole picture of someone's comfort unless you know the properties of the air. The left side of the chart is centered on wet-bulb and enthalpy, and the right side is centered on the absolute moisture content; the chart provides a comprehensive comfort profile if you use it correctly.

Dry-bulb temperature is the basic sensible temperature of the air and gives you a one-dimensional heat measurement. Wet-bulb temperature directly relates to the evaporative properties of water in the air; the wet-bulb temperature changes based on the moisture content even if the sensible heat stays the same. So, wet-bulb temperature gives us a better picture of the enthalpy, which is the total heat content (latent AND sensible). The wet-bulb temperature will usually be lower than the dry-bulb temperature, and the difference is called wet-bulb depression.

The only time when wet-bulb and dry-bulb temperatures will be the same is at 100% relative humidity, also called the dew point. At the dew point, the air can no longer hold any more moisture, so any additional water vapor in the air has no choice but to condense.

Bryan and Kaleb also discuss:

Radiant gains and dry-bulb measurements
"Cold air is dry air"
Relative vs. absolute humidity
What really is temperature?
Sling psychrometers vs. digital probes
Load calculations
Supply air and relative humidity
Insulation and humidity

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

A Huge Pricing Mistake - Short #93 Apr 28, 2020

Many contractors make a huge pricing mistake: confusing markup with margin. The distinction between those two things can be the difference between being profitable and losing it all.

If you want to mark up something that costs $10 by 50%, you multiply it by 1.5 to get $15. So, did we make a 50% gross margin? No; we only made $5 on a $10 transaction; if we take 10/15, we get o.66. So, we really only made a 33% gross margin.

When we factor overhead in, 33% is normally nowhere near enough. Not everything in the business will make money, and those costs become overhead costs. Businesses need to buy vehicles, pay for utilities, and save for emergencies, so you need a net profit from your sales to get enough money to pay or save money for those things. A good business makes 10+% net profit. If you don't do the math properly, you probably won't make that amount of money.

If you use a 40% markup in cases where you have 30% overhead, you won't make enough money. If we have $70,000 in revenue and multiply it by 1.3, you won't get $100,000. Instead, you take the cost of goods sold and divide the number you're charging for by the cost of goods sold. 70,000/0.7 will get you $100,000, which accounts for what you need to earn to break even with 30% overhead. So, for a 10% profit, you'd divide 70,000 by 0.6 (30% overhead and 10% profit).

So, using markup to set prices is a huge pricing mistake. The margins are where you really need to look. ("Margin" also sounds a bit better than "markup.")

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

A Frank UV discussion w/ Ron Saunders from Fresh-Aire UV Apr 23, 2020

In this podcast, Ron Saunders from Fresh-Aire UV comes on and answers questions about UVC. He clears up misconceptions and pulls no punches. Fresh-Aire UV (Triatomic Environmental) used to manufacture and sell ozone solutions, but the business evolved to sell UV and carbon-based IAQ solutions.

UV lights exist on a spectrum of varying wavelengths. Some UV lights at the higher end of the spectrum produce ozone, but UVC light does not. UVC's frequency (~250 nanometers) is outside the range of light that produces ozone (shorter than 185 nanometers).

Like any other IAQ product, UVC lights have advantages and disadvantages. To kill microorganisms, you need a mix of time, intensity, and proximity to the light. Since UVC effectiveness is so multifactorial, studies can be a bit misleading and can make the products look more effective than they really are by letting time and proximity make up for some slack in intensity. Visual light also doesn't necessarily reflect the light's intensity; you must be diligent about replacing them according to manufacturers' specs.

UVC lights can kill all microbes, including viruses like COVID-19. However, light intensity and air velocity are both factors that determine how effectively UVC lights can kill viruses. Viruses don't propagate on coils like mold, though, so you don't have to worry about viral "growth" on coils in the same way you'd deal with fungi or bacteria.

Ron and Bryan also discuss:

Benefits and drawbacks of ozone solutions and oxidizers
Time vs. intensity
"Airstream kill rate"
Viruses vs. fungi and bacteria
How to answer customer questions about COVID-19
UV lights and component damage
Handheld UV applications
Hydroxyl radicals vs. ozone
Scarce independent testing in PCO technologies
UV light and skin/eye disorders
Best COVID-19 product
Using UV lights in ducts
Measuring and detecting chemicals
Stray light and VOCs

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Q&A with Richard, Ross, and Evan Trethewey Apr 19, 2020

In this free-flowing conversation, the Trethewey family talks about growing up with This Old House, what the show is like behind the scenes, what Rich misses about the past, what the future holds for the trade, and some nerdy specifics between Bryan and Ross.

The show business is a collaborative effort between the producers and talent (even though they're real people, not actors), and the Trethewey boys find the end result almost cathartic. This Old House was never scripted; there were beats and predictions about the content, but the content is all authentic.

As the trade moves forward, Richard worries about weakening connections and producing leaks in the race to improve technology. He's glad that we work with far fewer deadly chemicals and materials nowadays, though. Many technicians are artisans at heart, and the future is bright because of techs who make ethical choices and do good, aesthetically pleasing work. (However, we can expect controls and ventilation to become increasingly important in coming years.)

Bryan and Ross also brainstorm some innovative solutions for residential applications by looking at commercial equipment. Bryan enjoys thinking about using R-290 chillers and buffer tanks for residential applications. Ross anticipates a future focus on CO2 as a residential refrigerant; he thinks the future "magic box" solution is a CO2 split system for heating and cooling.

Richard, Ross, Evan, and Bryan also discuss:

Exposure to media
Propane refrigerant
Heat pumps vs. natural gas
Hydronics
Staying organized
Pit corrosion on copper pipes
What it means to be an "expert" at something and how it feels
Core traits of successful skilled tradespeople
Passive makeup air solutions
New control strategies
Getting new people into the trades

Thanks to Richard, Ross & Evan for making this happen. Check out the This Old House podcast “ClearStory” on your favorite podcast player. You can also learn more about the Trethewey boys' work at TE2 Engineering and RST Thermal.

Learn more about Refrigeration Technologies HERE.

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TE2 Engineering

RST Thermal

Blower Doors ACH50 vs. Natural Infiltration Apr 16, 2020

Two of the great air and infiltration expert minds of our time, Gary Nelson and Steve Rogers from TEC (The Energy Conservatory), come on the podcast to talk about blower doors. They also discuss blower door testing and how it compares to real-life infiltration.

A blower door has a fan to measure the air flowing through it, and you generally install it in a doorframe. Blower doors hook up to manometers to measure the pressure differential between the inside of a building and the outside. Generally, you need to adjust the fan speed to bring the pressure differential down 50 Pascals. Then, you measure the airflow through the blower. That is how you determine how leaky a building is; all the leakage comes out through the blower door due to the pressure differential. We use blower door data and mathematical models to estimate the natural infiltration rate.

ACH50 is a means of expressing the leakage (air changes per hour at 50 Pascals). You take the CFM50 and multiply that by 60 to get the cubic feet per hour. Then, you divide that product by the cubic feet of the building to get your ACH50. You can apply a similar process to the surface area of a building instead of volume (though that's more common in commercial buildings).

During natural infiltration, the leaks can move inside or outside the envelope, so it's difficult to use the blower door test to measure infiltration accurately. Wind and extreme temperatures also affect natural infiltration, and testing can't account for those.

Gary, Steve, and Bryan also discuss:

Testing pressure variations
Analogies for measuring infiltration at 50 Pascals
PSIG vs. PSIA
Stack effect
CO2 and infiltration
Predicting infiltration rates with models
Infiltration in cold climates
How infiltration affects the latent load
Duct leakage and building pressure
Transfer grilles
Balancing with precision manometers

Check out The Energy Conservatory at energyconservatory.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Keeping your Scruples when Selling IAQ - Short #92 Apr 14, 2020

In this short podcast episode, Bryan explains how to keep your humanity and make moral decisions when selling IAQ products.

As the COVID-19 pandemic has started to grab hold of the world, we've seen an uptick in IAQ interest. When you have greater consumer interest, there are opportunities to hoodwink customers. While some IAQ products are indeed not very effective against viruses, there are some good products that you can sell to customers to benefit their health.

Pretty much every product has an appropriate application, but sales and marketing can lead to inappropriate, ineffective usage. Some techs sell IAQ products for inappropriate applications just to make a buck, but many others simply don't know any better. For example, UV and PCO technologies can work very well for certain applications, but they are not the fix-all that some people market them as.

When selling IAQ products honestly, you'll want to understand the efficacy data in the exact application you're selling it for. If you don't have the data for the application, don't make claims about efficacy. When it comes to oxidizers, you must also be transparent about safety concerns. Sure, you can explain how particles combine, but you also have to explain safety issues with the particles' behavior. Independent testing is also important. Paid studies can be manipulated to make a product look favorable. Ask if the product does what it's supposed to do.

Then, you have to ask if the product is safe. Cold plasma and oxidizing products are a bit less effective than other PCO technologies, but they are a bit safer. The goal is to educate yourselves and the customer so that you can both make the best decision for the customer's health.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Real Indoor Air Quality w/ Nikki from UltraAire Apr 09, 2020

Nikki Krueger joins us to talk about how humidity impacts indoor health and some ways to make our indoor air quality better (for real).

Indoor air quality is all about manipulating the air in our homes to reduce pollutants and keep our air quality high. From air dilution to running bath fans to air purifiers, there is a lot more we can do to make our homes healthier. We can't entirely isolate ourselves from viruses, bacteria, and fungi. However, there are many other things inside our homes that can suppress our immune systems, and we can address some of those things with IAQ.

To incorporate humidity control into our plans, we must look at the dew point. Dew point will change across the country and throughout the seasons, so we must work with varying conditions to keep RH in the 30-60% range. You can run kitchen and bathroom exhaust fans to manage moisture and VOCs. However, we also have to make sure the air we draw in is high-quality and won't upset people's allergies. So, ventilating dehumidifiers are an attractive option to replace exhausted air with high-quality fresh air.

Temperature is mostly about comfort instead of health, but filtration, ventilation, and humidity directly impact the healthiness of our indoor environments. When we can control those three things, we can create indoor environments that are truly healthy. Ultra-Aire dehumidifiers can tackle all three of those, but education and holistic thinking are the real solutions to healthier homes.

Nikki and Bryan also discuss:

Air dilution
Long-term payoffs
The tricky IAQ puzzle in multi-family buildings
Building design and IAQ
Talking to customers about ALL options
The "dehumidifier graveyard"
What makes Santa Fe Ultra-Aire unique

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Manometers - Short #91 Apr 07, 2020

In this short podcast episode, Sal Hamidi of ProductsByPros joins Bryan to discuss what manometers are and how they measure pressure.

Manometers measure pressure at a much higher scale than a micron gauge but lower than that of a pressure gauge; they measure pressure differentials by comparing static pressure to another source of pressure as a reference. Across all segments of the industry, we use manometers to measure static pressure. Static pressure is the pressure of air against the duct, not the actual air velocity. (Static pressure can give you an idea of the airflow, but you need pitot tubes or flow hoods to measure the actual airflow.) We can also use Magnehelics to measure static pressure, but it's just a specialized type of manometer.

We can also use manometers in conjunction with blower doors to perform zonal pressure diagnostic tests. Blower door tests require the technician to pull the house pressure down to -50 Pascals. Then, the technician uses a very precise manometer to help determine the air changes per hour (ACH). Manometers are also invaluable tools in markets with lots of gas furnaces, as they measure gas pressure. You measure gas pressure on the inlet AND outlet side of the gas valve to make sure the pressures are correct.

Every tech should have a regular manometer for everyday use to measure static or gas pressure. Techs on the building science side of the industry should have a precision manometer, which is an expensive but very precise instrument.

Sal and Bryan also discuss:

Pressure scales (in wc., PSI, Pascals, etc.)
Absolute vs. relative scales
Accuracy, precision, and resolution

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Is The Future of Air Conditioning Self-Contained Propane Chillers? Apr 02, 2020

Michael Housh and Jim Bergmann join Bryan to look into the crystal ball to see the future of air conditioning and design the PERFECT residential system.

Self-contained propane heat recovery chillers are futuristic devices that do simultaneous heating and cooling. While they may not be suitable for all climates, they can switch between heating and cooling modes, like heat pumps. They may also be able to service domestic hot water centrally as well. Although propane heat recovery chillers are impractical for residential use right now, they could hold the key to the future of air conditioning.

Geothermal systems sound like a great energy source in theory, but the cost of installation may not be worth the investment for many homeowners. You only get payback on geothermal when it's time to replace the unit, so it takes a long time to recoup your initial expenses. While these systems may work well in northern climates, you won't see many geothermal systems in the South.

Even though some customers have personal convictions about saving energy and efficiency, cost, effectiveness, and maintenance are going to be the most important factors to most homeowners.

One of the challenges to adopting new technology is the lack of knowledge of new technologies. We expect a lot out of technicians when it comes to knowing how components work and what they do. When we introduce technology-heavy new systems, it can take a long time for technicians to become proficient with those technologies.

Michael, Jim, and Bryan also discuss:

Pool heating
Equipment ROI
Solving the flammability problem of R-290
Radiant heating and cooling
Heat exchangers and piping resistance
Pre-conditioning outdoor air
Niches in the industry
Ice banks
New flammable refrigerants

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Filter + Fan = IAQ Revolution Apr 01, 2020

Thomas Talhelm, the founder of Smart Air, joins Bryan on the podcast to talk about how a filter and a fan in China sparked an IAQ revolution. The simple device changed his thinking about air purification.

As a graduate student in China, Thomas witnessed the Beijing "Air-pocalypse" firsthand. That was when he became aware of the issue of air pollution and the potential health issues it can cause. So, he dove into the world of air purification. The most popular air purifier on the market was about $1,000, but Thomas felt that the price tag was way too high for protecting human health.

Instead, Thomas decided to make his own air purifier with just a filter and a fan. He bought a laser particle counter to test his DIY air purifier and began publishing his data to make his health and safety data accessible and make cleaner air available to everyone. So, the goal of Smart Air is to lead an IAQ revolution by educating others about air pollution, sharing data about IAQ products, and improving health. The goal is NOT to earn lots of money.

Thomas also uses his own experiments and data to answer tough but practical questions. For example, he has done studies to discover if indoor or outdoor air is cleaner. (Of course, the answer depends on location, but it's still a question that we've needed to ask for the sake of consumer health.) However, educating consumers and being transparent about the data requires a delicate balance of marketing and communication.

Thomas and Bryan also discuss:

Social enterprises vs. non-governmental organizations (NGOs)
Smart Air in international markets
COVID-19 and masks
Being a researcher/professor
Organizing data
Sharing data in workshops
The future for Smart Air

Check out Smart Air at smartairfilters.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Inverter Voltage Problem - Short #90 Mar 31, 2020

In this short podcast episode, Bryan talks about the steady-state voltage problem that can take out inverter boards and what to do about it. Inverter-driven equipment refers to a variable-frequency drive with ECM compressors and fans.

We're talking about modern split-phase equipment rated for 208v or 230v power. However, the split-phase power will yield 240v. Most motors and components for 240v equipment have ratings for 230v AC power. L1 and L2 power can also be significantly higher than 240v, sometimes going as high as 250v.

Inverter boards have a widespread failing problem in locations with high steady-state voltage. Surge protectors only work for spikes in voltage, such as lightning strikes; they don't protect equipment from steady-state high voltage. Inverter boards are rated for 10% voltage over 230v and 5% lower than 208v. The operating range is 197-253v, but consistent overvoltage that doesn't quite reach 253v can still lead to failure.

We attempted to fix the problem by using the ICM493. These protectors have single-phase monitoring and have a NEMA 3R rating (suitable for outdoor usage). You can set the high and low voltage limits and get the benefits of thermally protected MOV surge protection. Although the inverters stopped failing, they started shutting off when they weren't supposed to. We discovered that the power companies were allowed to run up to 252v, which was right on the limit! Power companies may also run voltages 1-2v higher than 252v, so that explained the failures and shutoffs.

If you decide to use the ICM493, you need to calibrate the voltage based on measured voltage (such as from a voltmeter). Then, you set it for 230v +/-10%. If you experience recurring problems with overvoltage, the power company probably won't be much help. In that case, you can use a buck-boost transformer.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Testing A/C Vitals w/ Jim Bergmann Mar 26, 2020

Jim Bergmann and Michael Housh join Bryan to talk about testing A/C vitals. They discuss the new vitals mode in MeasureQuick and how it works. As with many of MeasureQuick's other functions, vitals mode is an invaluable tool for green and experienced HVAC techs alike.

The new vitals mode helps us with charging, airflow, and other staples of A/C testing and commissioning. Vitals mode allows the user to give MeasureQuick some information about the system; when they provide that information, MeasureQuick can instruct them to use the most appropriate charging method.

When you add enough refrigerant to create a liquid seal, you will begin to see a temperature drop across the evaporator. At that point, MeasureQuick would inform the user to stop charging and raise the airflow. MeasureQuick's vitals mode guides the user through the commissioning process by focusing on the main drivers: airflow and charging. The app also focuses on secondary drivers, including low-pressure, high-pressure, superheat, and approach.

You can get to vitals mode by hitting the "trending" button twice. At the bottom, you can start with the quick charge; you then choose your refrigerant and the charging method.

Vitals mode can help several new techs during the cooling season. The weigh-in feature helps prevent overcharging, which is a problem that's all too common. MeasureQuick has been working to fill the gaps in training by helping technicians do jobs correctly and avoid the confusion of listening to many different senior techs or trainers.

Jim, Michael, and Bryan also discuss:

Subcooling and line length
Approach
Sensible capacity vs. latent capacity
Target temperature split
Superheat
Trade school vs. field training for charging
Increasing the quality of HVAC instruction

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #89 - Liquid Line Temperature Mar 24, 2020

In this short podcast episode, Bryan explains how to use liquid line temperature as a quick diagnostic indicator on split A/C systems.

Liquid line temperature is one of the first things to check when you approach a system. Checking that temperature is also a great way to get into non-invasive testing. The temperature should be between 4 and 15 degrees warmer than the outdoor temperature (unless it is wet). If the liquid line is cooler than the environment, then there could be a restriction. If there is a restriction, you could have a clogged liquid line drier or a partially closed service valve.

When you have a larger condenser coil in relation to your capacity, your liquid line will be closer to the ambient temperature; the refrigerant must be at a higher temperature than the outdoor air to give off heat. You should also not see a pressure drop across the liquid line.

An important value is the condensing temperature over ambient (CTOA). On a normally operating piece of equipment, the condensing temperature will be 15-30 degrees above the outdoor temperature. The CTOA is a design feature that sets the differential between the saturation temperature and the ambient temperature. So, before the refrigerant subcools, it will be 15-30 degrees above the outdoor ambient temperature.

Subcooling goes below the CTOA. If we have a 30-degree CTOA and subtract 10 degrees of subcooling, then our liquid line will be about 20 degrees above the ambient temperature. If you add up all the numbers and find that the liquid line is warm, then you likely have an airflow restriction (dirty condenser, etc.). You shouldn't see a temperature differential across the liquid line; if you see one, then you likely have a restriction in the liquid line or lines that are too long.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Viruses, Bacteria, and Fungus #LIVE Mar 16, 2020

In this live podcast episode, we discuss viruses, bacteria, and fungi. We also explain how they interact with HVAC equipment, their effects on indoor air quality, and how businesses can protect their customers and employees.

Since we work with the public, we can minimize the risk of viral transmission by keeping our distance between others and avoid handshakes and other forms of contact. However, we also have to respect the feelings of the customers we're serving.

Many people confuse viruses, bacteria, and fungi (mold). All particles are small and would typically pass right through a MERV-8 filter; you typically need MERV-11 or better to catch all three. While our equipment can harbor those particles, the equipment can't create them. While bacteria and fungi can propagate on their own, viruses need a host to propagate. Viruses can go airborne, but they only grow and propagate inside our bodies. So, we don't need to worry about minimizing growth on surfaces or inside HVAC equipment.

We make it harder for bacteria, fungi, and viruses to survive by keeping the relative humidity between 30% and 55%. That is part of the reason why certain viruses become prominent seasonally, though our own immune systems are also a factor.

Probiotic cleaners also exist to attack biofilm on surfaces. To achieve that goal, probiotic cleaners promote good bacterial growth to fight the bad growth we want to eliminate. We may expect probiotic technologies to improve even more in the future. However, those won't affect viruses strongly because viruses don't GROW in equipment.

We also discuss:

Virus transmission
Masks and gloves
Mobile air scrubbers
HVAC technicians as essential workers
Microns
Legionella
COVID-19 vs. influenza
HEPA and activated-carbon filtration
Photocatalytic oxidation (PCO), bi-polar ionization, and UV lighting
Is oxidization effective?
Good vs. bad bacteria and probiotic cleaning

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #88 - Science vs. What Works Mar 10, 2020

In this short podcast episode, Bryan talks about science and how to balance practice and experience with the “why” behind what we do. He also explains how either one can cause an error if you aren’t careful.

Science is not just about reading nerdy theories in books; it's all about understanding why the processes in our world. In that sense, many of us field technicians are scientists. When we use problem-solving skills in the field, we try to understand what is going on and why our proposed solutions might fix the issue. We partake in experimentation all the time when we look for solutions, too; we formulate hypotheses about what will happen when we apply a fix, and we test our hypotheses by seeing what happens.

However, there has also been a rise in pseudoscience, which uses observation to come to a conclusion WITHOUT the due diligence of experimentation. We see this quite often in brazing; some old-timer technicians use poor brazing practices but still manage to get leak-free joints. While those brazing practices may work on the low side of the system, you can't expect the results to be the same when brazing in a compressor. The methods may "work" in some cases, but they're not backed by scientific understanding, so they can't produce good results under higher-pressure conditions.

Science is not perfect and can go wrong, though. When we don't understand the application and the "why" behind the work, we can't expect products and tools to work as they're meant to work. That's when errors pop up. To avoid those errors, investigate the "why" and test out your hypotheses.

Bryan also discusses:

Multiple ways to do things
Thomas Edison vs. Nikola Tesla
Poor brazing practices
Not pulling a deep vacuum
Ozone generators and deodorizers
"Hack" work

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

New Business Processes #LIVE Mar 06, 2020

We discuss some of the new, possibly strange-sounding business processes we've decided to implement at Kalos in 2020.

First of all, we are going to add terms and conditions that our customers must agree to. These terms and conditions include a "hold harmless" disclaimer regarding viruses, fungi, and bacteria. Florida forbids us from discussing mold, so a "hold harmless" disclaimer protects us from liability for something we aren't even allowed to discuss.

We also have to reinforce automobile safety to protect ourselves and our employees. Small fender-benders can spiral into serious legal problems when we lack proper evidence, so we decided to use GPS technology and dashcams in company vehicles. That way, we can collect more data on incidents to see who is really at fault in an accident. We've also clarified safety practices in our employee handbook.

New business processes also include changing how we pay people per diem. In our construction and refrigeration divisions, our employees eat and sleep out of town, so they need compensation. We've put new processes in place to reimburse employees for those expenses without taxing that money. We also set rules based on the time of year, zip code, and average food/lodging rates.

Overall, most of our new business practices are going into place to make Kalos a safer workplace with more efficient administrative processes

We also discuss:

Warranties on certain products
"Assumption of privacy"
Company credit cards vs. gas cards
Dispatch/service software
IRS "proof of transactions"
Nurse triage and dealing with injuries
Worker's compensation rates
OSHA training and SDS
Document signage and subcontractor agreements
SambaSafety
Slack vs. ServiceTitan
Keeping track of parts, inventory losses, and supply house plans
"Kaizen"

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

A Groundbreaking Motor Technology Mar 05, 2020

Ben with Infinitum Electric comes on to tell us more about his super-innovative, groundbreaking PCB (printed circuit board) motor technology that we saw at AHR 2020.

The Infinitum motor is a relatively simple permanent magnet motor that can also work as a generator. Infinitum got its start with generators, and the groundbreaking new motor technology works quite similarly to generators. These motors can also work with variable frequency drive technology.

In this groundbreaking motor, the traditional stator has all of the iron and copper taken out, and copper is etched into the circuit board. When you take the iron out of the equation, you eliminate core losses and get a much more efficient stator. Instead, electromagnetic waves travel through the air via flux transfer over the air gap, which rotates the motor. The machine has low inductance overall.

Energy efficiency is the core of Infinitum's philosophy. The original idea for Infinitum's motor came from optimizing performance in specific applications; Infinitum increased the efficiency while keeping the motors small and quiet. After that, the motor outgrew its application and opened the doors to innovation. There is great promise for Infinitum motors in the aerospace industry because they are lightweight, quiet, and highly efficient. However, Infinitum is also interested in short-term applications, including fans, pumps, and compressors in the HVAC/R industry.

Ben and Bryan also discuss:

Generator vs. motor technology
VFD system integration
How to operate motors with low inductance
Investors and why they choose to invest
Development of major automotive and aerospace technology
Serviceability of the motors
Using printed circuit boards as stators
Starting conversations with OEMs

Check out more about Infinitum and its new motor technologies at infinitumelectric.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Refrigerant Management Strategies w/ Rick Roland Feb 27, 2020

Rick from Certified Refrigerant Services joins us to talk about recovery and refrigerant management. He also explains what to look for and do to get the most from your program.

A refrigerant management program offers recovery services, reclamation, and other options for processing refrigerants. Rick's company also buys and sells refrigerants. With his line of work, there are also plenty of opportunities to educate contractors. The goal is to reduce refrigerant mixing and keep high-quality refrigerant in circulation.

Mixing refrigerants kills their value, though it is sometimes inevitable. On the contractor's side, you can take steps to prevent mixing by diligently using tags and weighing the charge each time. When we commit to careful recovery practices, we can keep high-quality, discontinued refrigerants available for people who have those systems. Contractors can also do injustice to their customers when they recover into dirty tanks, though it can be difficult to understand those tanks' histories. As contractors, we have a lot of difficult decisions to make, but we must always act ethically in terms of EPA guidelines and put the customers' needs first.

It's a bad idea (and illegal) to give customers unprocessed recovered refrigerant charges. You can't possibly know if the system has bad refrigerant (such as from a system that burned out) or other issues, so you're probably not helping anyone by giving them unprocessed recovered refrigerant. Quality is the key to the refrigerant management industry, and contractors can both contribute to the cause and benefit from it.

Rick and Bryan also discuss:

Refrigerant A/C vs. commercial chiller systems and mixing
Recycling R-22
EPA refrigerant disposal reports
Service vs. recovery cylinders
Being proud of being in the HVAC/R trades
How much should we really fill our tanks?
Life cycle of air conditioners
Refrigerant pricing
R-410A recovery

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

New Refrigerants from Honeywell Feb 26, 2020

Chris LaPietra, vice president and general manager of Honeywell Stationary Refrigerants, joins us to talk about some new releases from Honeywell. He also covers refrigerants in general.

As our industry reduces its reliance on R-22 (and eventually R-410A), we have turned to more flammable solutions. There is a tradeoff in safety for the lower GWP, though. However, along with some slightly less flammable A2L refrigerants, Honeywell is releasing two new A1 refrigerants: R-466A and R-515B (N-15). These are non-toxic, don't catch fire, and have a lower environmental impact than R-410A and R-22.

The Montreal Protocol was a groundbreaking initiative to phase out ozone-depleting substances to help slow down climate change. As a result, R-22 has undergone a phase-out. The Kigali Amendment is the next step, which addresses global warming potential and targets substances with high GWP for a phase-down. So, as R-410A will go in a similar direction to R-22, manufacturers have come on the scene; they are developing alternative refrigerants that address the global climate initiative. Instead of creating new HFCs, manufacturers are inventing new blends and HFOs to replace HFCs.

Honeywell wants to avoid creating undue risk in the marketplace. So, they take feedback from their customers and make sure technicians feel comfortable working with their refrigerants. They also keep the best practices pretty similar to those of working with R-410A.

Chris and Bryan also discuss:

Residential HVAC vs. commercial refrigeration solutions
The ZE product line
ASHRAE terms and definitions
How R-32 is made (and A2L refrigerant blends)
Global warming potential (GWP) vs. ozone-depleting potential (ODP)
How Honeywell develops new refrigerants
Trading off efficiency for lower GWP
E-cooling and the potential of the electronics market

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

EPA Myths and recovery Best Practices #LIVE Feb 21, 2020

Eric Kaiser comes on the live podcast to talk through some commonly repeated EPA myths. We also discuss how to get the most from your recovery machine and tanks. The EPA exists to interpret broad laws into specific standards, such as by translating climate initiatives into venting guidelines.

One of the most common EPA myths is that you cannot charge a leaking system. If you can repair the leak and get the leak rate below the specified percentage, then you can recharge the system. Not every country allows this procedure.

On the subject of refrigerant losses to leaks, making leaks is also NOT a valid excuse to vent refrigerant; the EPA tries to get us to minimize losses as much as possible. De minimis exemptions exist to allow for us to service a system properly, not to give us loopholes for venting. Overall, it's best to use probes to take your readings, not manifolds.

R-22 is another controversial subject that gives rise to some EPA myths. R-22 is NOT illegal, but it is no longer being produced or imported. There are limitations based on the amount of charge as well, but recharging a system with R-22 is NOT a crime.

When recovering with a recovery machine, you want to prevent junk from getting inside of it (such as from the recovery tank). To protect your recovery machine, it's good practice to run the refrigerant through a filter-drier when returning it to a system, though that won't fully clean the refrigerant.

Eric and Bryan also discuss:

The ins and outs of new R-22 guidelines
Pulling down into a vacuum
Low-loss fittings and refrigerant trapped in hoses
Whose responsibility is it to keep records?
Drop-in refrigerants, mixing refrigerants, and topping off
Recovery tank safety basics and cleanliness
How recovery machines work
Recovering in the liquid phase
Heat transfer in recovery
PPE

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

News from NATE w/ Gurminder Feb 20, 2020

Gurminder Sidhu joins us from NATE to talk about what NATE is all about and bring us some news about the new changes and improvements.

NATE was created for the industry by the industry; the organization arose from a need to promote education and standardize HVAC qualifications. Today, NATE continues to address the industry's needs by offering education and certification for technicians. NATE also understands the need of explaining the "why" behind our daily work.

The people at NATE also believe in continuing education and offer learning materials to techs of all levels, as well as study guides for their exams. People from all sectors of the industry contribute to the study guide content. These people also review it to ensure that everything in the guide is relevant and accurate. The study guides take what technicians have learned in the field and put them into a form that helps them prepare for quizzes. These guides also have practice questions, a glossary, and formulas.

Technicians must take a core and specialty exam before the big NATE exam. When it is time for you or one of your employees to take the NATE exam, you can arrange a date and time to take the test at a local testing organization.

NATE is currently working on an alternate pathway to certification for those who are new to the industry. This pathway has a series of five smaller exams that people can take in any order. You can take the alternative tests either traditionally or remotely with an online proctor.

Gurminder and Bryan also discuss:

Four levels of NATE certification
The study guide creation process
How employers benefit from employing a NATE-certified technician
New NATE user interface

Get started or keep up with news from NATE at natex.org.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

HVAC Design Mythbusting #LIVE Feb 17, 2020

Alex Meaney from MiTek/Wrightsoft joins us at AHR 2020 to talk about some HVAC design myths and how to bust them in your mind. It was a really fun talk with a great guy.

One common HVAC design myth worth busting is that we can use a set friction rate with a Ductulator to make duct systems work. The friction rate only applies per 100 feet, and it has different degrees of impact based on duct sizing and fan speeds. We CANNOT guarantee that a system will work if we subtract losses to filters, coils, and grilles until we reach a set friction rate (usually 0.1 or 0.8). We experience most of our pressure losses at the fittings, which the friction rate doesn't account for.

To prevent some of these myths, we can move away from manual math and start using more software. However, we have to know what our numbers exactly are and what the performance conditions are. For example, filters can show a static pressure drop rating of 0.1, but that WILL change depending on the CFM.

Velocity is a confusing area for techs because we have face velocity and duct velocity. Face velocity refers to the speed of air at the register whereas duct velocity refers to the air speed within the duct. These can get a bit complicated when you throw dampers in, but duct velocity doesn't have that much of an impact on the face velocity; the register has a much greater effect on face velocity than a damper in the middle of a duct.

Alex and Bryan also discuss:

Starting off by learning the wrong thing
12,000 BTUs per ton
Radial duct systems
What really is "static pressure?"
Oversizing ductwork
Creating vs. relieving friction
Manual D
Ideal velocity
Variable-speed technology
Efficiency vs. moisture removal
Sensible heat ratio (SHR) and Manual S
Latent loads

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Mentors and Role Models w/ Andrew Greaves Feb 14, 2020

Andrew Greaves joins us again from AHR 2020. This time, he discusses what mentors and role models do in our trade and why they're important.

Mentors are not just the grouchy senior techs who throw hammers at apprentices. Mentors have an active role in others' professional development; they spend a lot of time with their mentees and actively aid their growth. Not everyone is cut out to be a mentor, as the role comes with a lot of responsibility (and possibly stress). Role models indirectly influence others by doing good work and inspiring others to do the highest quality work; we should all strive to be role models.

However, the mentees need to put in a lot of work and must have emotional intelligence. Both mentor and mentee need to ask questions about the work and each other. The relationship is all about involvement and intentionality.

Mentors also have to care about their mentees as people, not just as students or technicians. They respect their mentees' values and acknowledge where their own shortcomings are when communicating with their mentees. However, mentors also know when to question and challenge their mentees when necessary. Mentees are entitled to clarity, and a good mentor understands that there has to be mutual understanding and trust in the relationship.

Relationships take time, and mentors usually need to give their mentees a chance to prove their work ethic before they commit to the mentorship. As a mentor, you must understand that your mentee doesn't have your perspective, and that's where empathy and expectation management are required.

Andrew and Bryan also discuss:

Individual learning styles
Formalization of mentorship
Investment in training vs. mentorship
"Multimedia" and internet mentorship
Dave Barefoot stories
How to start a mentor-mentee relationship
Filtering through unsuitable mentees
Setting expectations before goals

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

AHR 2020 Roundup from the Floor Feb 12, 2020

In this podcast, HVAC School team members Kaleb and Leilani walk the floor and talk to various people about their products and companies at AHR 2020. Bryan also has a quick conversation with Frank from HVAC Outlawz.

The newest RectorSeal surge protection (RSH-50 with the 60A disconnect) uses MOVs and gas discharge tubes, which work together to fight off power surges. The effectiveness of the product has allowed RectorSeal to give customers a lifetime warranty on their product. RectorSeal also has a new drain cleaner, Nu Line. Nu Line eliminates the biofilm in drains AND protects the drain from growth after cleaning.

One of Bryan's AHR 2020 highlights was speaking with Frank of HVAC Outlawz. Frank wants to push the limits of what we know so that we can perform the best work possible. In his 15 years, he has worked with a wide range of equipment. His experience led him to start creating content on Facebook and Instagram (also with inspiration from Andrew Greaves). He also involves himself in local trades education, which is the key to making our trade accessible to young people.

Emerson is also an HVAC titan that participates in events like AHR 2020. Emerson is at the forefront of new HVAC technology and always focuses on doing the right thing for contractors, wholesalers, and industry partners.

We also explore:

Gas discharge tube technology
Various applications for Line Sets Inc. products
Measuring duct pressures and velocities with Dwyer
Refrigeration Technologies Venom Packs
Maintaining building envelope integrity with Friedrich A/C
Recovery units with NAVAC
Emerson's Sensi Predict and Multiple Thermostat Manager
Fieldpiece vacuum pumps and Job Link probes
Ultra-Aire dehumidifiers
RGF Environmental Group REME Halo LED
Women in HVACR
Ultravation Synergy

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Building Performance Round Table Feb 10, 2020

In this live recording from the AHR Expo, Kaleb Saleeby, Nate Adams, Michael Housh, and Steve Rogers discuss building performance.

The building science world is an exciting place; we're all excited about improvements to reheat dehumidification, which is when we use waste heat to take care of humidity without cooling. As equipment becomes more efficient, we also look forward to tackling new challenges that make us think more broadly. New people are also stepping up, using new tools, accessing more knowledge, and doing better work.

Building performance is becoming more important in HVAC via HVAC 2.0, which focuses on design efficiency. However, the biggest challenge right now is making HVAC 2.0 sustainable and profitable. We must simplify and scale building performance; when we make it accessible, we can work it into the HVAC industry and do more thorough work.

One of the challenges to widespread adoption is the lack of experience with building performance. The average technician simply doesn't have the needed exposure to building science concepts and practices. Perhaps the best way to bring people into the building science side of the business is to work on the techs' own homes. We need to bring the personal part of building performance to the technicians and their families if we want to see widespread adoption of HVAC 2.0.

We also need to make building performance solutions accessible to the consumers. Although the solutions may be too expensive for many customers right now, the goal is to start holistic comfort conversations.

Kaleb, Nate, Michael, Steve, and Bryan also discuss:

Tapping into the engineering mindset
Economic sustainability
Psychrometric charts vs. app-based learning
Math vs. software
Working with techs and the CSRs
The Gulf of Disappointment
Contractor relationships
Economic and environmental impacts
Fossil fuels
Upgrading the electrical grid
Propane

Learn more about Refrigeration Technologies HERE.

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Live w/ Mike from Refrigeration Technologies Feb 08, 2020

Mike from Refrigeration Technologies talks to us about his journey in business, some new and old products, and how well the business is growing.

Refrigeration Technologies tries to make products that do the job correctly the first time and are safe for techs to use. The products are odorless, don't burn skin, and are safe around food. John and Mike Pastorello are passionate about using chemistry to make quality products that make techs' lives easier. Mike joined his father's business full-time when he was 23; he performed a lot of the menial tasks while his father developed the products.

Nylog is perhaps one of the most popular yet controversial products. The product is made of refrigeration oil, which is inside the system anyway. While many people may be suspicious of additives to avoid warranty complications, nothing inside Nylog will harm the system. It also won't clog the lines when used properly.

Lately, Mike and John have made highly concentrated cleaners that have taken all the excess water out of coil cleaners. These Venom Packs are pure concentrate, meaning that they are very strong but maintain their original cleaners' non-toxic properties. They are also easier to store and come in brightener, all-purpose, evaporator, and condenser varieties. Refrigeration Technologies cleaners also work on tough bacterial zoogloea, a common plague in humid climates like Florida.

The Pan & Drain Treatment also works very well to clean out and treat drains. The spray is also tough on odors.

Refrigeration Technologies has experienced a lot of growth recently. Most of the company growth happens in John's lab, as the products are constantly getting better. The goal is to improve the quality without raising prices, and improvements to packaging are crucial to that element of growth. The company is also very active on social media and actively takes feedback.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Richard w/ This Old House Shares His Story Feb 06, 2020

Richard Trethewey from This Old House joins Bryan on the podcast and tells his incredible story and shares some encouragement and laughs.

Richard works with his sons, Ross and Evan. He has always worked in a family business and then left it to start his own with his sons. Family businesses truly are the backbone of this industry, as our business attracts lots of family-oriented business owners. Richard's sons volunteered to join the business early on.

This Old House started off with a phone call from PBS about a home-renovation show idea; Richard had to start the show from scratch with no money, but his father agreed to do the show. The first years of the show were difficult because that was before Home Depot and the internet became popular, so DIY home renovation was still pretty new and unknown; Richard worried about "selling the secrets" of the trade. However, his main concern was with doing good work and setting a positive example for others whenever they watched him.

If Richard had to give one piece of advice to young people, it would be to join the skilled trades. Many high-profile jobs have an ebb and flow of good workers, but the skilled trades ALWAYS need good workers. Regardless of where people are or what the market looks like, people will need comfort. One of the most rewarding things about being in the skilled trades is being able to inspire others to obtain the skills to provide for themselves.

Nowadays, Richard spends time learning about new technologies and feels excited by the prospect of making American technology even better. He looks to Western European HVAC technologies as an example of what we can do. Richard also looks forward to empowering and inspiring the new generation and getting them to a point where they have pride in their work.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Micron Gauges - Products by Pros Feb 03, 2020

This podcast is by Sal at Products by Pros, featuring Bryan Orr of HVAC School. In this episode, Sal asks Bryan all about micron gauges.

Products by Pros

Guest: Bryan Orr

What should technicians look at when deciding on a micron gauge?

You should look for superior accuracy and resolution, especially if you'll be doing decay testing. You need to see what the trends are in clear detail. (The Bluvac app makes that easy.)

Why should a tech even use a micron gauge?

You use a micron gauge to verify that you have pulled a proper vacuum.

What role does fear or pain play in the use of micron gauges?

People respond primarily to pain; most technicians in the field know what they can get away with to avoid the pain of punishment for bad practices.

What type of technician doesn’t care about proper vacuum or micron gauges?

They typically come from companies that don't care about having clear startup and commissioning practices.

What is the cost of adoption for high-end tools?

Technicians think in terms of the tyranny of the urgent. They have to take time to learn it, and many of them don't have that time.

What are the pressures techs deal with?

Scheduling pressures are already immense, and field techs are also under constant pressure to get work done and do their jobs even better.

How can techs save time and relieve pressures?

Learn how to do things right and become proficient with newer, better tools.

How do you pull a proper vacuum?

Don't use leaky manifold gauges during evacuation; just use good-quality vacuum-rated hoses. Use core remover tools and keep your micron gauge as far away from your pump as you can get it during evacuation.

What are the incentives for techs to do things properly?

A common thread among many techs is that they want to avoid blame; if we focus on reducing blame, then techs might feel more encouraged to learn and do things correctly. (There will always be sticks in the mud, though.)

What role does integrity play when it comes to business owners doing things properly?

Integrity comes in when we show techs how to do procedures right. When you teach techs how to do things right, the work will speak for itself, and your company will earn a positive reputation.

What micron gauge from AccuTools would you suggest for technicians?

I recommend the Pro for new techs or installers, the LTE for intermediate technicians, and the Micro for pros.

Why do you consider AccuTools micron gauges reliable?

I consider those products reliable because they work consistently with the typical wear-and-tear that's expected in the field. Except in cases of extreme abuse, they seem to maintain their sensing abilities very well.

Looking to learn more? Go check out hvacrschool.com/evac or the AccuTools YouTube channel HERE.

Want to have your local suppliers carry AccuTools? Reach out to sal@productsbypros.com

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Connecting STEM and HVAC w/ Rachel Kaiser Jan 23, 2020

Rachel and Eric Kaiser join us to talk about connecting STEM concepts to the trades. They also explain how to teach STEM in a way that sticks.

STEM refers to science, technology, engineering, and math. In traditional classroom settings, teachers usually tout these subjects as the ones that lead to the most promising careers. However, STEM concepts are not limited to their respective subjects; we use many of those scientific and mathematic concepts in the trades as well.

Rachel believes that undergraduate programs would be more effective if they focused more on teaching critical thinking and less on making students meet requirements for degrees. Eric believes that traditional education needs to be more holistic; right now, trades education fixates on details; that approach may help for teaching specific tasks, but it doesn't broaden the students' knowledge.

We can start talking about STEM more broadly when we start eliminating stigmas around STEM topics. For example, many students dislike math, but many of those people still use math effectively in several real-world applications without knowing it. We can break down that stigma against math to start having productive discussions and connecting STEM to the trades and other careers. The next step is to spark interest in others so that they seek out new STEM knowledge.

The HVAC trade has many scientific concepts in play, even though we focus on diagnostics and field techniques at work. Most of our diagnostic skills are informed by the principles of heat transfer and phase changes.

Rachel, Eric, and Bryan also discuss:

HVACR Training Symposium
Undergraduate vs. graduate programs
University research and funding
Principles of algebra in real life
Gas laws and galvanic corrosion as chemistry concepts in HVAC
Theoretical vs. diagnostic vs. instructional applications
Continued learning vs. degree programs
Applications and limitations
Hands-on BEFORE theoretical
Choosing to learn
Improving safety and productivity through education

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #87 - Our Install Reminders Jan 21, 2020

This short episode is a review of a list of installation reminders made by Kalos manager Jeff Crable. Kalos is doing a bunch of these installs for a commercial customer. Hopefully, the business leaders can take a few things from our checklist and help out their installers.

Whenever we do an install for our large commercial customers, we give our installers a long checklist of reminders; that way, they can do the best install possible.

Some of those install reminders include:

Don't rush the details.
Ensure the drain line is clean, pitched correctly, trapped, ventilated, and insulated.
Install float switches in the unit and auxiliary pan. Wire in series and test.
Replace the auxiliary drain pan or ensure that it's in good condition and has proper sizing.
Hang the auxiliary drain pan WITH Unistrut; don't hang with wire.
Install a new thermostat.
Attach and hang the ductwork properly; silver-tape will NOT support duct board plenums.
Replace incorrectly sized breakers (for licensed electrical contractors only).
Replace old and faulty disconnects (for licensed electrical contractors only).
Ensure that the outside conduit is watertight or replaced.
Anchor condensers properly with isolators if the pad is attached to the building foundation.
Mark the unit with the correct number using paint and stencils or vinyl stickers.
Post pictures of the units and data tag in the appropriate location in our communication software; make detailed notes.
Address vertical air handlers and take them as they come.
If a unit is in a difficult area, try moving to a more accessible place if you can.
Pour gallons of water into the drain pan and observe draining. Listen for noises of concern.
All work will be checked by lead techs or managers. Get everything right the first time if you want a full bonus.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Reversing Valve Diagnosis & Replacement w/ Kaleb Jan 16, 2020

In this face-to-face discussion, Bryan and Kaleb share some tips for diagnosing and replacing the reversing valve on a heat pump. These valves may also be known as four-way valves.

Kaleb and a trainee recently had to diagnose a heat pump with a scroll compressor. The motor was also over-amping due to a failed capacitor, and the compressor was making a metallic grinding noise. Because reversing valves are pilot-activated, they need a pressure differential to shift, so the scroll plate can sometimes pop up and make noise during bypass. Another possibility was that the compressor could have been running backward, but that wasn't the case.

There are some cases when techs misdiagnose a compressor problem as a reversing valve failure; however, in Kaleb's case, there was a problem with the reversing valve that then caused compressor failure.

To determine if a system has a reversing valve issue, you should look at the temperature difference across the valve (more than 3 degrees). Another thing to look for is an abnormally low compression ratio (high suction, low head pressure). You also want to watch the compressor amperage, as it will likely be lower than normal. When doing more advanced tests, such as delivered capacity tests, use Bluetooth tools to make your life a lot easier; that way, you can clamp your probes on.

When Kaleb replaces a reversing valve, he cuts them out wherever possible. If he can't cut them out, he sweats them out and sweats the new one in. Sometimes, it's also easier to remove the entire condenser coil during replacement.

Kaleb and Bryan also discuss:

Common suction port
Causes of compressor damage
Unreasonably hot discharge lines
Compressor amperage drop
Common suction, common discharge lines
Kaleb's compressor replacement
Cutting out suction dryers
Sweating out reversing valves in Trane units
Purging with nitrogen before a pressure test
Deburring properly

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #86 - Hoodwinked Jan 14, 2020

In this short podcast episode, Bryan talks about the times he has been hoodwinked in his career. It's time to name and shame.

One time at a trade show, Bryan came across a product called KVAR. KVAR is already an electrical term for kilovolt-amps reactive; those are volt-amps that show up and generate heat but don't do anything useful, just like foam in a beer mug. So, the product supposedly balanced out the power factor to save energy. However, power companies don't charge based on VA; they charge based on wattage, which already accounts for the power factor. So, the KVAR products made no actual difference; the KVAR motor was simple and very inefficient, which did little to improve energy savings.

Bryan was hoodwinked because he didn't ask the right questions. He should have asked about the difference between volt-amps and watts, and he should have asked to see hard data about energy savings.

Hoodwinking happens quite often in our industry; the only way we can prevent it from happening to us is to learn more and ask the right questions. So, how do we avoid hoodwinking? The best thing we can do is ask to see the data. Don't accept platitudes, graphs, or name-dropping; ask about the test methodology and specific details.

Indoor air quality (IAQ) is an area that has a high potential for hoodwinking. Unfortunately, the IAQ products' data is often incomplete and only tests for a few contaminants. While the products have the potential to do a lot of good, there is potential for deceptive marketing and lazy science.

Something to remember, however, is that not everybody who hoodwinks you has bad intentions. They sometimes don't understand what they're doing or are more familiar with marketing than science.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Pool Heater Talk #LIVE Jan 12, 2020

This live podcast episode is all about pool heater talk. We cover gas pool heaters and pool heat pumps, explaining how they work and common issues.

Pool heat pumps work a lot like air conditioners, but they have heat exchangers that help transfer their heat to the water. Instead of having a typical condenser, a pool heater has a unit that works like a heat pump's outdoor coil in heat mode. There is usually an option to cool the water, but there are almost no cases where someone would want to use that mode.

The heat exchanger is the core component of a pool heater, and this part has evolved a lot to improve efficiency and reduce the effects of water chemistry. The old designs were cupronickel tube-in-tube heat exchangers where the refrigerant and water flow in opposite directions. Unfortunately, these corroded and failed easily. Titanium coaxial heat exchangers replaced those, though they can still fail. If heat exchangers fail, water can get into the refrigerant circuit; when that happens, the whole heat pump will fail prematurely. Actuators are also components that commonly cause issues.

Gas pool heaters work similarly to gas furnaces, so they tend to work better than heat pumps in low-ambient conditions. However, they have their own set of challenges. They have very short lifespans in Florida and corrode easily because steel, heat, chlorine, and water all interact in the same area. Inducer fans especially tend to rust out easily.

We also discuss:

Manufacturer quality control
Hooking up gauges
Water level and flow
Low ambient conditions
BTUs
Float switches
Internal thermal overload
Heat and water pressure losses
Temperature sensor issues on pool heat pumps
Pool vs. spa mode
Special considerations for indoor pools
Flame rollout
Cleanliness issues
Double-lugging
Circuit breaker failure
Piping configuration and valves

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

R290 Facts and Service w/ True Refrigeration Jan 09, 2020

Alejandro Rios from True Refrigeration comes on to talk about self-contained R290. He explains what it is, why to love it, and how to service the sealed system.

R290 is pure propane, and it has recently made a name for itself as an emerging refrigerant. It is an A3 refrigerant, meaning that it is non-toxic and highly flammable. As we move away from HFCs and other refrigerants with high global warming potential (GWP), we will encounter more flammable refrigerants, usually A2L and A3 refrigerants. R290 is a natural refrigerant and has a GWP of only 3, making it more attractive than 400-series blends and some A2L refrigerants. You can also vent R290 because it has such a low GWP and an ozone-depleting potential (ODP) of 0.

Self-contained systems that use R290 have a relatively small charge. However, they effectively run colder coils. Due to the colder coils, these systems have a net refrigeration effect (NRE) about 30% better than previous equipment models with other refrigerants. R290 is also versatile and can work in medium and low-temp refrigeration.

Many of the service procedures are quite similar to other refrigeration systems. However, you have to be EXTRA diligent to check for flammable gas leaks; you must use a combustible gas meter for leak detection, NOT your typical electronic leak detector. Like most self-contained equipment, True's equipment is factory-sealed, and you must braze in your own service ports. However, as long as you vent the refrigerant in open areas and purge the line with nitrogen, you normally don't need to worry about anything catching fire.

Alejandro and Bryan also discuss:

Regulations for self-contained systems
Terminal venting
High-efficiency R410A systems
Small charges
Residual refrigerant and evacuation
Adding service ports and sealing them
Refrigerant recovery with SHORT hoses
POE oil
Energy savings

Check out True's YouTube channel HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #85 - Low Voltage, Low Voltage Jan 07, 2020

In this short podcast episode, Bryan explains what happens when your low-voltage circuit puts out a lower voltage than it should.

Bryan recently received an email asking about the low voltage on a 20-ton split system with a long control wire; the voltage coming back to the condenser is only 19 volts, so there was some contactor chattering. First, in a case like that, you'll want to figure out why the voltage isn't as high as it should be. The control wire and line sets could be longer than the design specs, which may contribute to the problem. If the distance between components is the main issue, then you can use a relay to mitigate voltage drop and amp draw.

You'll also want to check that you've tapped the transformer correctly. Since most transformers are single-phase, they'll probably start off tapped to 240v; when you're dealing with three-phase equipment, you must ensure that the transformer is tapped to 208v.

One of the obvious issues to check is the voltage drop. If 26 volts are coming out of the transformer but you're only measuring 19, then you're clearly losing volts and have some resistance. Think about ALL of the conductors; is the drop the same across all of them? If so, then you've likely got a length and wire sizing problem. You can correct that issue with proper wire sizing; you can't always control the length, but if you can, then it's a good issue to address. If there's an issue with only one conductor, then the switch could have a problem, or there might be some wire splices.

If the load is drawing higher current than it should, then something could be impeding the motion on the solenoid, contactor, or another electrical component.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Codes and Failed Inspections #LIVE Jan 02, 2020

In this live podcast from the Castbox app, we talk about codes and common causes for failed inspections. We talk about these topics both broadly and with some specifics.

Many of the places where we fail to meet codes are on the electrical side. Electrical components have fire and electrical shock hazards, and codes are stringent for arc and ground fault protection. Leaking current to ground can shock someone, and arcs can cause damage to property and human life. We commonly see failed inspections due to improper marking on the air handler.

In the HVAC industry, we have specific wire and breaker-sizing codes for our trade (440 in the NEC). Inspection failures are common in this area, as it's easy to leave the incorrect breaker in place. You also must have a disconnect or easily accessible circuit breaker that can function as a disconnect. In our market, we must also insulate drains and show proper attention to strapping, pitch, float switches, and cleanouts; otherwise, the drains may fail inspection (though it's rare).

Clearances also come up quite often and are especially relevant to safety in our industry, as we don't want condensers blocking panels. Obstructed rooms or lack of egress are also common code violations related to safety. Anchorage is another safety-related code category, and there are special requirements in locations that are prone to high winds (like Florida) or earthquakes (California). You can't assume that units installed on rooftops have been anchored correctly, so be sure to check the anchorage.

We also discuss:

Pulling permits
CO detectors
PVC primer on condensate drains
National Electrical Code (NEC) vs. AHJ
Catwalks in attics
Duct sealing and mastic vs. metal tape
Florida Energy Conservation, Mechanical, and Building Codes
Customer complaints
Furnace venting and GAMA tables
Smoke detectors
Locking caps
Wire protection
Sealing boots

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

FURNACE TALK #LIVE Dec 20, 2019

In this live podcast episode from the Castbox app, we have four techs join us to talk about common furnace issues and best practices.

Those of us in heat-pump-dominant markets rarely have to worry about common furnace issues related to gas pressure and flow. In that same vein, we also don't have to worry about clocking the gas meter, which is a common practice on gas furnaces. Checking input and performing combustion analysis is critical to the diagnostic process AND can give you an idea of the unit's safety. There is no reason NOT to do combustion analysis when commissioning a furnace.

Furnaces also have electrical components with flashing error codes. You must be careful when interpreting those codes, as multiple issues could show up under one code. (Compare it to going out on high pressure; that error doesn't necessarily indicate a pressure switch issue and could entail other problems.) Common codes deal with the flame sensor, but flame sensor failure is rare; the issue could come down to simple maintenance. When cleaning parts, the most important thing to do is make sure the carbon and debris come off; you don't have to overthink the cleaning material.

Cracked heat exchangers are common issues that can present unsafe conditions, though they won't always have CO problems. If there is an issue with a cracked heat exchanger, the technician usually CANNOT turn off the system at the gas. (We usually CAN shut off the power at the switch, though.) Only the gas company can typically shut off the gas.

We also discuss:

Restrictions at ports
Adjustments for altitude
Carbon monoxide poisoning
Proper drain line
Clocking the gas meter in commercial settings
Gas pool heater problems
Parts that commonly need cleaning
Steel wool vs. sand cloth
High limit codes
Clogged burner wings
CO-monitoring
Venting issues and negative pressurization
Intake/exhaust pipe issues
Power passing vs. consuming

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Mixed Air Temperature w/ David Richardson Dec 19, 2019

David Richardson with NCI, author of Duct Dynasty, joins us on the podcast to talk about mixed air temperature and more topics of interest.

When you bring outside air into the home, you introduce positive pressure into the home. That way, you can offset air lost via mechanical ventilation or through cracks, improving air quality. We often assume that the building will "breathe," but tighter constructions make it difficult for the home to bring in enough fresh air to offset harmful chemicals and VOCs.

We need to measure two different kinds of airflow: fan airflow and outside air. When we have these numbers, we must figure out how much air is coming through the outside air intake. The fan airflow represents 100% of the air content after mixing has taken place. You can perform a duct traverse to get the airflow measurement; when you plot the fan airflow, subtract the two to know how much return air you're getting BEFORE mixing with the outside air.

Once you have your airflow measurements, you must break those into percentages. You must determine the percentage that matches up with the temperature you want to use for the mixed air. Subtract the outside air from the fan airflow to get the CFM from your baseline. You could get 95% of your airflow from the return and 5% from the outside. Once you know the outside air temperature and the percentage of outside air, you will know how much the outdoor temperature will affect the return air and space temperatures.

David and Bryan also discuss:

How David got into writing
Blown-in cellulose insulation
Designed and undesigned leakage
Duct traverse tools and procedure
Dry-bulb vs. wet-bulb measurement applications
SEER vs. AFUE
Duct leakage

Learn more about NCI at nationalcomfortinstitute.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #84 - Power Passing vs. Consuming Dec 17, 2019

In this short podcast, Bryan briefly explains why we use a voltmeter to measure “voltage drop” across loads and switches. He also covers some of the differences between passing and consuming power.

Many of us are naturals at using voltmeters already. Voltmeters have two leads, and those exist to measure the difference or potential between them. Voltage is a reference to what is going on between the leads; whenever resistance exists, we have a voltage drop. Resistance can sometimes be designed or undesigned.

When we think about power passing and consuming, we should note that "consuming" refers to turning energy from a usable form to an unusable one. Stored energy becomes potential energy when it needs to do work. Power consuming results in work; a coil in a contactor or a filament in a lightbulb is a load (the load has resistance). On the other hand, power-passing components do not have resistance, and the charges merely move. We must keep the intended resistance in mind whenever we measure the voltage of energized components; resistance will impact the voltage drop.

If you have a high-limit furnace safety, you will want to measure the voltage drop across the limit. There should NOT be a voltage drop across it because it is a power-passing component; there should be no resistance. Of course, you must determine if there is an energy potential present in the first place. Conversely, you SHOULD see a voltage drop when measuring the potential across a heater or fan motor.

Overall, wires and switches are power passing components that should not have voltage drops across them. Heaters, compressors, and fan motors are all loads that "consume" power.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Impactful HVAC/R Instruction Dec 12, 2019

Ty Branaman from NTI comes on the podcast to share his passion for teaching. He also discusses his approach to impactful HVAC/R instruction.

It can be difficult for instructors to create an appropriate balance between teaching theory and practical knowledge. Students and trainees need to have technical skills in the field, but they also need a solid foundation. Impactful HVAC/R instruction requires a balance of the nerdy stuff and physical skills; good instructors put the theoretical parts simply and give students the opportunity to apply theory to hands-on skills.

Engagement is another important part of HVAC/R education. If students are sitting down for 15 minutes, that's too long; the students need to be moving and active with the learning material to stay engaged and help the topics stick. Ty emphasizes the importance of spending time in the lab instead of staying in the classroom the entire time.

Unfortunately, many trade schools nowadays don't prepare students for fieldwork because there is not enough emphasis on working with equipment in education programs. The best teachers are those who love teaching AND working in the field, and trade schools need more people who are passionate about BOTH. Passionate technicians need to get involved in education by offering to be a substitute or guest speaker or by joining an education advisory board.

Ty and Bryan also discuss:

Teaching the refrigeration cycle
What the current generation values and needs in education
Dealing with distractions in the classroom
Using mobile apps to supplement learning
Teaching newbies effectively
Creating an HVAC/R instruction program on a budget
Old equipment
Getting involved in education
How to guide young people in their careers
"Thinking outside the box"

Check out Ty's YouTube Channel HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #83 - Practical Safety Improvements Dec 10, 2019

In this short podcast, we take a quick look at Bryan’s take on practical safety improvements. He also discusses the safety year in review at Kalos.

Kalos had a great year in terms of safety. As the managers look back on the year, they attribute their success to having a practical approach to safety. To make practical safety improvements, we must be safety-conscious without obsessing over the risks of our job. Our jobs always have an element of danger, and our goal should be to minimize those and abide by OSHA standards.

As an industry, we can do a better job of wearing our eye protection on almost every job. Ear protection is also an area we tend to neglect, especially in motor rooms and industrial environments. Ladders also provide a clear source of danger; we need to make sure our ladders are secure (tied off, set on level ground, etc.) and place some responsibility on our customers to give us a safe work environment.

Electrical safety is also critical. Especially on commercial jobs, we should use proper lockout-tagout procedures when we can't monitor the power source while we work on equipment. We must also verify that no power is present after we shut off the disconnects.

We also experience some fire safety threats, especially while brazing. Eye protection and gloves are critical if you want to keep yourself safe while brazing. (Gloves are also important when cutting sheet metal.) You should also know where fire extinguishers are anytime there is a fire risk on the job.

Perhaps our most dangerous work environment is the road. We must avoid texting while driving, drunk driving, and other unsafe practices. We must also drive defensively to avoid accidents with other commuters who partake in unsafe driving practices.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Descaling Large Equipment Dec 05, 2019

Tim Fregeau from Goodway joins us to talk about descaling large equipment. He also discusses best practices and why they matter to you.

Scale refers to mineral deposits that build up in any water source. Water can be brackish, rusty, muddy, or otherwise high in mineral content, and those minerals begin to accumulate on heat-transfer surfaces on large equipment. Scale can cause metallic components to weaken and leak, and it can block microchannel coils. The large equipment can't reject the heat efficiently or function as it should when it has scale buildup, so that's where descaling comes in.

When it comes to chillers, you can either brush or chemically clean the tubes to remove scale. There will be times when you physically cannot brush the tubes, so you must rely on chemicals to descale the equipment. When you use chemicals, you pump the chemical solution into a low point of the condenser and make it come out of a high point. Factors that influence success are the chemical makeup, flow rate, and pump size. Boilers are quite similar to chillers, but the higher water temperatures come into play.

Various chemical agents have different functions. Acids dissolve calcium, and inhibitors protect the base metals. Wetting agents reduce the surface tension and allow the chemicals to spread out. Penetrating agents allow the chemicals to get deeper into the mineral deposit to dissolve calcium and free up the rest of the deposit.

Tim and Bryan also discuss:

Plate heat exchangers
Separating open loops from chillers
Goodway clean-in-place systems
Chemical selection and dilution
Circulation time
Why track oil levels and approach temperatures?
Compression ratio and system efficiency
Common cleaning challenges and mistakes to avoid
Water pH
Calcium spot tests
Goodway products
Legionella

Check out Goodway's site HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #82 - Brazing Temperature Dec 03, 2019

In this short podcast episode, Bryan talks a bit about brazing temperature. He also covers how to heat your copper to the proper temperature. You can use torches with oxyacetylene or air-acetylene tips.

Joining two metals with an alloy above 840 degrees classifies as brazing; anything that uses an alloy to join two metals below 840 degrees is technically soldering. When you join two similar metals by melting the base material (not using an alloy), that's welding.

Another temperature of interest is 500 degrees; oxygen rapidly bonds to copper at temperatures above 500 degrees, so we will want to flow nitrogen while brazing to prevent cupric oxide (black scale) from forming on the copper. (We always recommend flowing nitrogen even if you are soldering below 500 degrees.)

When brazing with a 15% silver alloy (with a phosphorus fluxing agent), you will want to reach a temperature of 1100-1200 degrees. Solidus is when the rod gets a putty-like consistency. However, we want liquidus, which is when the alloy can flow freely into the joint. The color of the copper will be either dark or medium cherry. To be clear, you DO want to see redness when brazing; the color shouldn't be very bright red or orange, but a dark or medium red is ideal. The brazing indicators hold true for copper-to-steel and copper-to-grass brazing as well.

Aluminum brazing should stay below 1200 degrees; aluminum also doesn't have the same color indicators as copper, steel, and brass. Steel is complicated because it has a lower melting temperature, but it has much lower thermal conductivity than steel, so it will take longer to heat up and may heat unevenly.

You also CANNOT use an alloy with a phosphorus fluxing agent when brazing steel or brass; you need a silver alloy with a separate flux.

Learn more about Refrigeration Technologies HERE.

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Heat Pumps, Charging & Defrost #LIVE Dec 01, 2019

In this live episode, we talk about heat pumps, why Bryan likes them, why other people don’t, charging and diagnosing them, and defrost.

Even though heat pumps work best in warmer climates, they can theoretically work as long as the temperature is above absolute zero (-460 degrees F). Viewers across the USA install heat pumps in their markets, even in places with cold winters like Wisconsin. Ideally, the discharge line should be around 100 degrees above the outdoor temperature in heat mode. Although this rule of thumb appears to work in many different climates, it is only really applicable on single-stage equipment.

When charging heat pumps from scratch, check the manufacturer data in heat mode. Airflow for comfort or efficiency is something else to account for when you're commissioning a heat pump; the CFM should be higher if you want the system to be efficient, but the building will be more comfortable if you have a lower CFM per ton. Airflow is especially important to control in heat mode, as small changes can noticeably affect head pressure.

When it comes to defrost, heat pumps typically use a time and temperature strategy. Defrost cycles usually run at a certain temperature for a fixed time period. Heat pump defrost boards usually look a lot more complicated than they really are; when you come across them, stay calm and remember that they're just like any other board.

We also discuss:

Absolute zero
Climate zones
“Vapor line”
Discharge superheat vs. over ambient
W calls
Supplementary heat and dehumidification
Confirming airflow on a heat pump in heat mode
Controlling mean radiant temperature (MRT) vs. blowing hot air
Using in-duct psychrometers and manufacturer charts to assess system performance
How reversing valves may fail or get stuck
Thermal imaging applications
Copeland compressors and mobile app
Testing defrost boards
Carrier vs. Trane & Rheem defrost strategies
Demand defrost
Suction pressure and compression ratio under frost buildup

Learn more about Refrigeration Technologies HERE.

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IT DOESN'T VOID THE WARRANTY #RANTCAST Nov 28, 2019

In this crossover episode (rantcast), Bryan talks with Gary from HVAC Know It All. They vent about some of the phrases that techs throw around that are often false.

Technicians often throw around the phrase, "[X] will void your warranty." However, the truth is that manufacturers can't really void a warranty. Some modifications may go beyond the scope of the warranty, but you don't simply make modifications that "void" the warranty. Techs may say that something voids the warranty to shut down the conversation or to create a selling point (preventive maintenance).

In many (but not all) cases, the manufacturer won't even check the installation in the case of a parts warranty; all they want is the returned part, and they will often honor the warranty. Since many manufacturers want to keep their customers, voiding warranties left and right would be a bad business decision; the customer base would opt to work with new manufacturers.

However, if there is evidence that the customer, installer, or technician damaged the product, then the manufacturer has a reason to void the warranty. In several cases, the proof must be substantial, and the proof often isn't substantial when using natural additives like Nylog properly. Keep in mind that using additives comes with a calculated risk; you must rely on research and your own judgment to make the best decision for the customer.

In this rantcast, Gary and Bryan also discuss:

R-22 is not illegal
Heat exchanger warranties
Lightning and other "acts of God"
The Nylog question
Why use thread sealants on well-made flares
Relationships with manufacturers and suppliers
Warranties and original homeowners
Putting the customer's needs above the manufacturer's
Who really is a hack?
How everyone in the distribution chain can take responsibility
Complaining respectfully online

Learn more about Refrigeration Technologies HERE.

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Short #81 - Air vs. Nitrogen vs. Oxygen Nov 26, 2019

In this short podcast, Bryan discusses the differences between air, nitrogen, and oxygen. He also explains why we should only use nitrogen for purging, flowing, and pressurization.

You DON'T want to pressurize line sets with air because air contains water vapor and oxygen. Water acts as an oxidizer, and moisture can turn POE oil acidic via hydrolysis. You cannot dry out POE oil, and the acid can lead to compressor burnout.

Nitrogen is non-reactive (unlike oxygen) and does not contain water vapor (unlike air). It also does a good job of chasing water vapor out of the lines. Because nitrogen won't react with anything we put in the line sets, it is an ideal medium for purging, flowing, and pressurization. Nitrogen DOES, however, change pressure with temperature; it obeys the gas laws, and you can see it in action when the pressure changes at different parts of the day (with varying temperatures).

Oxidation can occur when oxygen reacts with copper to create a black scale called cupric (copper) oxide. It is similar to rust on iron; it is an undesirable form of corrosion. When the black scale comes off, it can get into screens on filter-driers and clog the system.

You purge nitrogen to chase all of the air out before brazing. When you've finished purging, you use a flow regulator to reduce the nitrogen pressure (2-5 SCFH) to flow it during brazing. When we pull the vacuum, we only want nitrogen to be in the system; exposure to air should be very short, and any air in the system should be temporary.

So, again, it's not a good idea to use air to pressurize the lines.

Learn more about Refrigeration Technologies HERE.

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Inverter Driven Systems & Over-Voltage #LIVE Nov 24, 2019

In this LIVE episode, we talk about diagnosing inverter-driven systems. We also discuss some of the issues and solutions for over-voltage.

Inverter-driven systems, also called variable frequency drive equipment, provide comfort control across multiple zones in a building. Some systems may have multiple branch boxes that control various units throughout a building. These systems require a lot of patience; the diagnostic process can last a long time because you must test all of the terminals. Since these systems are very electrical-component-heavy, you may also encounter issues presented by lightning, power outages, or continuous high voltage. Installation errors are also common and can cause performance issues, such as incorrectly torqued-down terminals, nicked wires, and improper wire types.

When these systems are on, line voltage runs into a bridge rectifier. So, the equipment takes alternating current (AC) and turns it into a form of direct current (DC). Capacitors smooth out the sine waves before running that current into the inverter, which switches the power into three separate phases, but the power doesn't look like typical three-phase AC power.

Many power companies are familiar with single-phase AC equipment, so inverter-driven systems present a challenge. These challenges become clear in equipment near the initial power distribution source; inverter-driven equipment near the beginning of the power line is prone to excessive voltage and failure.

We also discuss:

Power surges and electrical damage
ICM493
Loose connections
Grounding
Shielded conductor usage
Pulse-width modulation (PWM)
230v-rated equipment
Multi-stage equipment and airflow
Bernoulli's principle
Carrier Infinity equipment and locking out stages
Ductwork and diffuser sizing
Controlling radiant heat loads with multi-stage equipment
Ventilation vs. dehumidification vs. heating and cooling
R-22 retrofit refrigerants
Metal oxide varistors (MOVs)

Learn more about Refrigeration Technologies HERE.

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High Efficiency Gas Furnaces, Common Issues w/ Jim Bergmann Nov 21, 2019

Jim Bergmann is back on the podcast. This time, he talks about common faults with high-efficiency 90+ condensing gas furnaces and their installation.

Like A/C units, 90+ furnaces often suffer from clogged drain lines. Other common problems stem from issues with inputs, temperature rise across the appliance, trapping, and venting. On high-efficiency gas furnaces, procedures like clocking the gas meter are much more important than on an 80% gas furnace; you must clock the gas meter to get the proper inputs. To get the furnaces to condense properly, you need to make sure you control excess air and get the temperature rise in the correct range.

During the adjustment process, combustion analysis remains important as ever on 90+ gas furnaces. CO poisoning is always a deadly possibility on any sort of gas appliance work, and too many things can go wrong. You must use a combustion analyzer every step of the way.

In high-efficiency gas furnaces, you essentially condense water out of the fuel-air mixture. (Think about water dripping out of your car's exhaust pipe in the winter.) Many furnaces counterflow, meaning that the flue gas gets pulled down instead of wandering upward. We need cold return air to meet with cool flue gases for optimal condensate production.

Two-stage 90+ furnaces also use two-speed induced draft fans, which normally require an exhaust accelerator. Issues pop up in retrofit systems when we don't update the venting system to prevent the recirculation of flue gases. Two-stage furnaces tend to be very efficient, but they may not be as comfortable as single-stage furnaces.

Jim and Bryan also discuss:

Chemical causes of premature failure
Orifices, fuel pressure, and impingement
Heat exchangers
Order of operations for checking condensate drainage
CO poisoning
Byproducts of combustion
Energy savings of 90+ furnaces over 80% furnaces
Interlocked systems
Filtration

Learn more about Refrigeration Technologies HERE.

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Short #80 - 3 Differences Between Followers and Leaders Nov 19, 2019

Bryan explains the core differences between followers and leaders. There is nothing wrong with being a follower, but if you are ready to move into leadership roles, here are his tips.

Leaders primarily leverage the work of other people. Conversely, followers have limits to their abilities and their earning potential; the leaders are the ones who set those limits. Good leaders create opportunities for others.

Followers who attempt to be leaders are more likely to wait rather than move, complain rather than change, and assume rather than ask. Leaders actively seek out opportunities and tend to act rather than wait and assume that opportunities will come their way. Followers also accept but complain about the status quo, whereas leaders work to change their circumstances.

Communication is a major area of difference between followers and leaders. Leaders ask questions, communicate, and propose ideas or solutions; followers typically hesitate to initiate communication and expect others to give them answers and opportunities.

Followers also tend to think in terms of what they would do, not what they can actually do; they don't realize their abilities to make a difference and would prefer that the changes happen from the outside. On the other side, leaders seize opportunities to initiate change and create opportunities for other people (even if those are opportunities to fail safely). Moreover, the mark of a good leader is the number of followers who agree with their vision; leaders are also willing to make sacrifices for their followers and manage their resources well.

True leaders also know how to listen to others, think broadly, and be kind but truthful; they don't take pride in being "brutally honest" or "knowing it all."

Learn more about Refrigeration Technologies HERE.

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Ductless and VRF - Good, Bad & Ugly #LIVE Nov 16, 2019

Some great live guests join the podcast to discuss the advantages, disadvantages, and challenges of ductless and VRF equipment.

We started off working on ductless equipment with Mitsubishi, especially installing them in lanais. Sunrooms have large amounts of radiant heat coming in, and the heat load often warrants getting an A/C system just for the sunroom/lanai. We even began oversizing them a bit (which was a lesson learned). We also learned that mini-split ductless systems tend to have filthy blower wheels because moisture tends to build up on them. However, bib kits make cleaning the blower wheel in place an easy process.

High-wall ductless systems also work in houses, not just sunrooms. However, they may have issues dehumidifying effectively. To remove more latent heat, you have to ramp down your blower and ramp up your compressor to get your coil colder. Overall, Bryan is not a large fan of using multi-zone ductless units in residential applications UNLESS they are replacing window units.

VRF systems are typically used in commercial applications. The systems typically use cassette-type units or low-static fan coils, unlike high-wall ductless units. Although VRF and high-wall ductless units tend to have different sets of advantages and disadvantages, both of them struggle a bit with humidity and may need supplemental dehumidification.

Overall, while VRF and ductless systems are desirable because they can control sensible capacity, those modulation capabilities can also lead to serious problems in wet climates.

We also discuss:

Condensate pumps
Blower wheel set screw issues
Ductless and VRF filtration
Sensible heat ratio (SHR)
VRF serviceability
Dehumidification vs. efficiency
Regional VRF manufacturing practices
EER vs. SEER
Daikin dry mode
What should HVAC systems really control?
Engineering commercial buildings
VRF refrigerant loss
ICM493 controls

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Floating Head w/ Jamie Kitchen Nov 14, 2019

Jamie is back on the podcast. This time, he talks about the merits and pitfalls of floating head pressure and why you might care.

There is a relationship between floating head and floating suction, though the latter is easier to understand. You can stage fans to come on at certain temperatures, but you'll always be running fans above a certain temperature. When temperatures are below that temperature, you can save energy by not running the fans. However, you still have to worry about feeding the evaporator coil sufficiently. Floating head pressure refers to dropping the pressure differential across the metering device while letting it feed the evaporator coil properly.

Allowing the head pressure and temperature to float is beneficial in applications that use large amounts of electricity and have low profit margins, such as grocery refrigeration. This practice is also great for energy savings in mild climates that stay below 80 degrees for most of the year.

To use floating head, you first have to look at your metering device capacity. The metering device must have enough capacity to feed the evaporator coil and compressor adequately for the load conditions. Then, you must look at your other components' capacity balance, namely your evaporator and compressor. Sometimes, you also have to use floating suction to combat dehumidification issues that may result when you use floating head pressure.

Jamie and Bryan also discuss:

Energy efficiency benefits of floating the head pressure
Compression ratio
Fan staging and variable-speed fans
Metering device sizing for load demands
Electronic expansion valves (EEVs) vs. TXVs
Evaporator and compressor sizing in relation to each other
Evaporator pressure controls
Oversized condensing units
Temporary fixes to save product vs. permanent fixes
Ease of locating and purchasing replacement parts

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #79 - Circuit Breaker Facts Nov 12, 2019

In this short podcast episode, Bryan talks about circuit breaker facts. He also explains why they trip, what they do, and some different types and considerations.

Circuit breakers break the circuit during an overcurrent situation. These do NOT handle all overloads, such as locked rotor amps (LRA); these handle significant overloads, such as shorts (when current takes undesigned paths). In air conditioning, we can size our fuses and circuit breakers a bit larger than usual, which prevents tripping from small spikes instead of truly dangerous or prolonged overload conditions.

There are thermal and inductive circuit breakers. A thermal circuit breaker uses heat to determine when to trip; these are common breakers but are prone to nuisance trips from poor connections or on days with high ambient temperature. Inductive trip breakers are magnetic and trip at a certain point of inductance; these are not easily affected by ambient temperature but can be expensive.

A breaker's temperature can tell you a bit about its condition. Hotter breakers may be closer to tripping. However, arc fault breakers, a type of thermal breaker, can also run hot but work fine, which may confuse technicians. You can use thermal imaging cameras or infrared thermometers to compare breaker temperature.

Dielectric grease is a good tool but requires plenty of attention. You need to have the right connectors before you even reach for the grease. The dielectric grease protects the connectors from corrosion (from the outside), and it should NOT go directly on the connectors. Some people also use anti-seize grease; no matter which grease you use, you must be careful and avoid adding resistance.

Bryan also discusses:

Proper torque settings
Measuring voltage drop across the device
Using breakers as switches
Double-lugging
Arc fault vs. GFCI

Learn more about Refrigeration Technologies HERE.

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The Lost Art of Steam - Revisited Nov 07, 2019

In this episode from the archives, Dan Holohan joins us on the podcast and talks about his vast experience in the lost art of steam learned from long-dead men.

Steam heating is a "lost art" nowadays; it has become increasingly uncommon and has been disappearing since the Vietnam War. Many people who understood steam heating either retired or died after the Vietnam War. Many elements of steam heating are difficult to understand or surprising. (For example, steam pressure has a surprising relationship with velocity: low-pressure steam moves through piping much more quickly than high-pressure steam.) So, Dan Holohan is on a mission to revive that knowledge and teach the newer generations about the lost art.

There are many older steam heating systems still operating today, especially in the older large buildings in New York. Dan learned a lot about steam heating when working on these old systems and optimizing them. Most of the time, he optimized those systems by removing unnecessary accessories, not adding components like steam traps.

Many old boilers used coal as a heat source. Nowadays, many old boilers have been fitted with conversion oil burners with thermostats, but they are still piped for coal. Some systems now have multiple risers or massive vents on the main riser to prevent the thermostats from getting too hot too early and satisfying the thermostat too early. We call that master venting, reducing pressure and allowing steam to move very quickly and efficiently.

Dan also discusses:

The 2-PSI standard
Transportation metaphors for BTUs in steam
Harmful renovations for old boilers
Replacement vs. restoration mindsets
Gaps in steam boiler education
Monopolizing the market if you HAVE the education
Boiler piping and venting
Two-pipe vs one-pipe steam

Find out more about Dan and hydronic heating at HeatingHelp.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

What Makes a White Shirt Tech #LIVE Nov 04, 2019

In this honest—maybe overly honest—live podcast, we talk about the dark side of white shirt techs. We also discuss ways the industry can make money while doing the fundamentals well.

The term "white shirt" refers to a sales technician who prioritizes selling equipment over fieldwork; these technicians don't necessarily sell expensive products, but they lack technical expertise. The surefire way to tell if someone is a "white shirt" is to see if they can solve problems with their hands or if they just pull solutions from a menu of new products.

However, "white shirts" do have some skills we can learn from. They are usually great communicators, which is an excellent characteristic in our trade. Honesty is also important, though, and great communication can only be a good thing if it's backed up by honesty. "White shirts" lie, and they make excuses for their lies.

Unfortunately, many of us want to do good work and make less than "white shirts." The problem may not be with the white shirt technicians; we contribute to the problem by undervaluing our expertise and quality work.

Strangely enough, we rarely ever see white shirt technicians in commercial HVAC. That's because commercial HVAC is a far more expensive, less sales-oriented part of the industry. There is less of a need to push products onto the customer to make money.

We also cover:

The fine art of setting prices
Sales tactics
Made-up simplified product names ("heat rejector")
Honest, straightforward, non-emotional communication
Vetting technicians
Deceptive training by salespeople
What drives people to sell extra accessories
"White shirt" profit margins
Labor rates, diagnostic fees, and maintenance prices
Hard start kits and potential misunderstandings
Bad intentions vs. ignorance
Billable time in residential vs. commercial HVAC
Buyer's remorse
Consulting vs. sales
Surge protection

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Callback Prevention Principles Oct 31, 2019

In this podcast episode, Bert joins Bryan to talk about what he has learned to help prevent the dreaded callback on the job.

Callbacks are bad news for customer service, time, and profit. However, the highest cost is the inconvenience caused to the customer. To reduce callbacks, Bert recommends communicating your expectations to your customer clearly; explain what the expected performance should be and how a customer should use their system. We need to do better at having conversations with the customer where we listen to them; we should not explain everything through the paperwork and walk away.

Customers become less of a callback risk when technicians stay with them until they are no longer a risk. The technician must run the equipment to ensure that it's working and set expectations before they leave. This tip can be a bit tricky, as many of us have to move from one emergency to the next, but the extra time and effort will almost surely help prevent a callback. The goal is to get a system to last as long as possible without having a problem.

Overall, hard skills are less important than soft skills when it comes to callback prevention. Many techs have the technical knowledge; far fewer take the time to listen to the customer and get the whole picture of the problem. When it comes to hard skills, callback prevention requires more attentiveness and skill application than the technical skills themselves.

With all that in mind, the ultimate key to preventing callbacks is to take responsibility for ALL of your work: testing, setup, communication, and fixes.

Bert and Bryan also discuss:

"White-shirt" techs
"Callback risk" customers
Reducing loads by adding insulation
How rain and temperature affect performance
Recognizing a customer's budget
Checking for wire rub-outs and loose/poor connections
Visual observation

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HER

Short #78 - 7 Tips for Newbies Oct 29, 2019

This short podcast is for the newbies out there. For HVAC trade newbies, Bryan recommends applying 7 tips to help you win.

When you start off in the trades, you'll want to check your mindset. Successful HVAC technicians are usually humble; recognize that you don't know everything. The truth is that nobody knows everything, and every other person has wisdom and knowledge to offer you. (However, don't mistake humility for a lack of confidence.) You'll also want to hang out with good people; you are the sum of the five people you spend the most time with, so you don't want your friends to drag you down intellectually or get you into trouble. (And make good use of your time!)

Stay hydrated on the job! Water is the very best thing you can have on the job, especially during hot summers. To take care of your body, you will also want to wear safety glasses on the job and gloves when appropriate.

Curiosity is also an incredibly important trait of successful techs. Push further to understand your work fully, and you will be much more successful in your career. If you are curious, you will bring more ideas to the table and have a better grasp on the work you do, which will hopefully help you get raises and promotions. Another extension of curiosity is to test what you know. Pursue a possibility and find all of its weaknesses; don't accept a solution as the truth without further investigation.

Perhaps one of the most useful tips for newbies is to learn to be okay with failure. You sometimes won't have everything you need, whether that's a lack of tools or knowledge. Making difficult situations work is part of the job, and the fear of making mistakes should not hold you back.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Why is a Power Quality Meter Useful? w/ Jim Bergmann Oct 24, 2019

Jim Bergmann returns to the podcast to talk about the power quality meter. He also discusses what it is good for and how to use one.

A power quality meter accounts for the power factor in its measurements, and it measures true power in watts. We can notice failing capacitors and other issues that can cause a device to draw higher wattage. In inductive loads, the power factor will be less than 1. However, we can measure the power factor because the capacitor counteracts the inductive reactance and gets the power closer to unity; the current and voltage should be in phase with each other, so the circuit should be balanced.

The main difference between watts and volt-amps (VA) is the power factor. Volt-amps represent the entire quantity of energy, watts represent power, and volt-amps reactive represent useless energy. So, the power factor is the difference between what makes watts useful and VA reactive unuseful. (Think about a pint of beer, which is VA: you can't drink the foam, which represents VA reactive, and the actual liquid beer is the watts. Unity would represent a pint of beer with no foam.)

When looking at EER and SEER, the power quality meter helps you get a more accurate wattage reading, which allows technicians to determine efficiency more easily. You MUST know your power factor to measure wattage properly. Since consumers are billed on wattage, an accurate measurement is critical to make sure they're paying an appropriate price for energy.

Jim and Bryan also discuss:

Supco Redfish iDVM550
Matching capacitors to inductive loads
Fan efficacy and PSC vs. ECM motors
Back EMF
Considerations for measuring frequency
VFDs
BTU capacity, amp draw, and efficiency
Commissioning and benchmarking with power quality meters
Single-phase vs. three-phase power factor tools

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #77 - What Causes Capacitors to Fail Oct 22, 2019

In this short podcast, Bryan talks through (once again) what REALLY causes capacitors to fail and what we can do about it.

High temperatures and overvoltage (NOT undervoltage) are what cause capacitors to fail. (There are also some poor manufacturing practices out there. Remember: they should be just foil and oil.) Capacitors create a phase shift to assist split-phase induction motors. Normally, a three-phase motor can start and run just fine because the sine waves are all angled. That is not the case for split-phase motors. Start capacitors help startup, which is difficult for the motor.

The capacitor stores and discharges each time there is a cycle change (usually 60 times per second). That rapid storing and discharging helps create a lag that gets the motor get moving. However, capacitors are limited by their design: their charge capacity (current) is dictated by size (microfarads), voltage, and frequency. If you measure amps on the start winding, you will notice that the amps are lower than on the run windings; the capacitor acts as a limiting factor.

When the run capacitor fails, you have no current on the start winding. The motor does NOT cause the capacitor to fail; there is a slim-to-none chance that a motor's back EMF can cause capacitor failure. Excess temperature or voltage is what really causes capacitors to fail, and THAT can negatively affect the motor. The hotter a capacitor runs, the shorter its life will be. Locations with high temperatures year-round and lots of thunderstorms will have more capacitor failures than places with more temperate climates.

Capacitor oil also plays a role in longevity. Oil exists for heat dissipation and should be mounted with the terminals up. Condenser cleanliness and temperature can also help or hinder the oil's efforts.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Commercial PM Best Practices #LIVE Oct 20, 2019

Eric Mele, Eric Kaiser, and John Oaks come on the podcast to talk about commercial PM best practices and what matters most.

Drain cleaning is a critical part of the standard commercial PM. You must assess the drainage situation (pitch, length, location, etc.) to plan your cleaning strategy and arrive at the best result: the entire drain gets cleaned. If you use chemicals, you need to be very careful not to let them back up into other units.

Condenser coil cleaning is another important PM procedure in both residential and commercial HVAC. However, you don't always need to clean the condenser coils. When you actually need to clean the coils, some best practices include splitting multi-row coils (on VERY dirty systems) and washing the coil against the airflow (usually from the inside out).

Lots of commercial equipment use belts, so HVAC technicians should know how to work on them. Unfortunately, many HVAC technicians aren't great at aligning and tensioning belts. Bryan is of the school of thought that many belts that are adjusted should just be replaced.

When working on gas equipment on rooftops, you can perform very accurate combustion analysis because the flue is in an ideal location for testing. Grilles are also very important in commercial HVAC, and the best practice is to check them for restrictions.

As always, you cannot underestimate the importance of visual inspection, "do no harm," and making sure the equipment is running when you leave.

The Erics, John, and Bryan also discuss:

Drain pan cleaning tips
Neutralizing algae in drains
Clearing drains with nitrogen or shop vacs
Transfer pumps
Paperwork and documentation
Environmental reasons NOT to clean coils needlessly
Microchannel coils
Quoting specific procedures
Belt longevity
Browning tools and literature
Checking for phase imbalance
Benchmarking equipment
Maintenance people vs. technicians
Communication

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Skills Gap and Training #LIVE Oct 17, 2019

In this live podcast from CASTBOX, we discuss the skills gap and how we are going to get more people into and trained in the HVAC/R trade.

Instead of gaining skills early in life and then looking for a job, many of us in the HVAC/R trade started our careers and gained skills along the way. The most successful technicians (and Bryan's favorite job candidates) have the "growth" mindset and care about their work, not just connecting a paycheck. Many people have experience working with their hands (or working any job), but they don't go into the HVAC industry with trade experience under their belt. Work ethic and care for one's work are more indicative of success than prior skills.

From a contractor standpoint, Bryan thinks that we must teach and force the application of skills. The basics are important, and being a "hands-on learner" is not an excuse for a technician not to learn the basics. Repetition and muscle memory are a major part of learning in our trade; however, they are undervalued in the classroom. It's all about striking a balance.

As a society, we don't see as many people involving their family members in the trades. As a result, our trade currently has a hiring and skills gap. It's up to us to get people excited about the trade and help them get involved. We must make it clear that HVAC/R careers ARE good careers where you CAN make a nice living.

We also discuss:

Hiring out of desperation
Self-control and maturity regardless of age
Successful techs from other industries and hard times
The Diagnosis Game
Company culture
Successful communication
Formal vs. informal performance reviews
Interpreting hiring exams, interviews, and phone calls
Proficiency timeline and career evolution
Learning without an internal training program
Competitive starting wages
Better high-school programs
Socratic method
Getting younger people involved in the trades and job-shadowing
Being safety-conscious
Apprenticeship programs
HVAC/R teachers
Being intentional about training

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Who is Responsible for Proper Sizing? Oct 17, 2019

In this episode, Nate Adams and Michael Housh give the HVAC 2.0 rebuttal to the idea of standard load calculations. They take a different, possibly more radical approach to proper sizing.

Michael and Nate believe in doing real-world load calculations, not just relying on models for load calculations. They are on the side of replacing equipment like-for-like unless the customer will pay for the proper load calculation; customers should have the option to get a free quote for a like-for-like or slightly smaller replacement or a full consultation, but they will often opt to choose the free quote for a similar or slightly smaller unit. The full consultation includes blower door tests and load calculations, which are keys to proper equipment sizing.

Even once we do all the typical tests for consultation (blower door, duct leakage, load calculation), there is still some room for ambiguity. The tests are not all-telling, but they exist to help the contractor and homeowner decide what the next step should be. No matter what, there will be some degree of guesswork, but there will be far less guesswork if you perform all the tests and look at utility usage.

Some problems can be "HVAC'd away," but excessive leakage may require work on the actual shell of the home to address cracks and infiltration points. To "HVAC problems away," proper equipment sizing will play a major role in promoting comfort.

Nate, Michael, and Bryan also discuss:

Like-for-like tonnage
Building customer relationships through consultation
Windows and radiant heat loads
Natural pressurization vs. blower door testing
Sizing increments and room for error
Air changes per hour (ACH)
Assessing leakage rates
Moisture problems and dehumidification
Load calculation theater
The consumer-oriented mindset
Diagnostic pyramid
Natural leakage
Communicating testing practices to your sales team

Learn more about Nathan's work, go to energysmartohio.com or natethehousewhisperer.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #76 - The Freon Sniffer (A True Story) Oct 15, 2019

In this true story from Bryan's teen years, you learn about the "Freon Sniffer:" what inspired him to become an HVAC/R technician (maybe).

When Bryan was working with his uncle at age 14, he was an electrical apprentice who worked in grocery stores. He installed "pink lights," which were lights that hung on aircraft cable over produce displays. (The aircraft cable came from Bryan's grandfather's aircraft junkyard.)

The pink lights were difficult to install, and many people were unwilling to do the installation. However, Bryan and his family were willing to install that difficult equipment. Bryan primarily assembled the lights and didn't do any particularly dangerous work. Bryan and his family traveled around the state, staying at hotels and working at grocery stores across the state.

In a remote Florida town, Bryan's uncle and a coworker discussed something about checking a "Freon sniffer." They promised to show Bryan what that was. All they said was that "Freon sniffers" just existed to check for refrigerant leaks in the refrigeration piping.

What really was it? They tricked Bryan into pressing down the disconnect fitting for the produce sprayer, which sprayed Bryan's face. It was all just an elaborate prank to humiliate him!

If nothing else, the situation inspired Bryan to learn more about HVAC/R equipment. Maybe in the future, he wouldn't have the wool pulled over his eyes.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Use a Combustion Analyzer w/ Jim Bergmann Oct 10, 2019

In this podcast, Jim explains how to use a combustion analyzer. He also talks through the process of combustion analysis using Accutools BluFlame.

The beauty of BluFlame is that it can do CAZ testing, help you set the inches of water column in your furnace, and measure static pressure drop. BluFlame is a tool you can use year-round, not just when you need to measure stack gas.

To learn how to use a combustion analyzer on a typical gas furnace, you have to understand why you're doing it. Combustion analysis is necessary to monitor the health of a furnace system; it's like a doctor measuring your blood pressure at each appointment. You must test for carbon monoxide to protect the homeowners from a potentially deadly situation; combustion analysis can save lives.

First, we have to test for ambient CO, which can be high in cities with lots of cars and air pollution. Then, we start deploying our tools and set them up to check our pressures. After that, we can start the furnace up to collect our readings all at once, which is easy with MeasureQuick. From there, we can use the readings to help us adjust the input settings. After that, we put our analyzer in the stack about 12-16 inches away from the draft inducer motor.

Jim and Bryan also discuss:

Jim's involvement in BluFlame
Testo probes that do and don't work with BluFlame
Clocking the meter and checking input
Manometer locations
Drilling and sealing holes for testing
CO air-free and excess air dilution
Overexposing the analyzer to CO
Oxygen (O2) content
Vacuum in gas furnaces
Draft direction
Running gas furnaces with other gas appliances (stoves, fireplaces, pool heaters, etc.)
Electronic gas leak detectors
BluFlame on 80+ vs 90+ furnaces
Other gas appliances that require testing

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #75 - Stop Duct & Unit Sweating Oct 08, 2019

Duct and air handler (unit) sweating is a common issue in humid climates. Bryan talks about what causes it and what to do about it.

Many people try to keep their ducts and equipment either very cool or very warm to prevent sweating. Despite the good intentions, neither of those methods is great for sweat prevention. If a ceiling grille is sweating, people try to insulate the top of the boot to stop the sweating. The real reason why the grille continues to sweat is that those sweating areas have hit the dew point.

If anything reaches the dew point or lower, you WILL see condensation. Another potential cause is that air with a higher dew point is going into the lower-dew-point space. In the latter case, sealing the ducts and cracks near the boot should help that higher-dew-point air from infiltrating; insulation does very little to address leakage, so air sealing is the real solution. Attics often have air with a higher dew point than the conditioned space.

Equipment sizing is also important. Oversized equipment leads to shorter run times, meaning that the evaporator coil can't get cold enough to remove moisture. When you have a low latent capacity, you won't have proper moisture removal in the home.

We will almost surely encounter sweating when we have air handlers and ducts in unconditioned spaces. To address duct and unit sweating, some technicians increase the air velocity to prevent ducts from sweating, as the higher temperature should prevent the duct jacket from being below the dew point. However, as with oversized equipment, excessive airflow will negatively impact the latent capacity. So, you will have less moisture removal. The best solution is to decrease the attic dew point or increase duct insulation. Reheat solutions are also worth considering on some systems.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Stop Designing Ducts Backwards w/ Alex Meaney Oct 03, 2019

Alex from Wrightsoft is back to discuss duct design. He also explains a common mistake made when designing ducts using a Ductulator.

The Ductulator is a common entry point for technicians who get into duct design, so it sticks with technicians despite its flaws. It makes more sense to reverse the process by picking a friction rate and pressure drop as the first step when designing ducts. Figuring out how to overcome restriction is the key to commercial duct design, but it can also work well in residential duct design.

However, we can't pull our desired friction rate out of thin air. We have to consider the sources that contribute to the friction rate. We must also consider both velocity pressure (moving forward) and static pressure (pushing against the duct walls). The less restricted the air is, the more energy there will be to go forward; low static generally indicates greater velocity (more airflow). The best designers understand these principles, so many of the best designers come from the HVAC service industry.

You can adjust the airflow by balancing duct sizing and restriction, such as from filters. Equipment sizing and Manual S are surely important, but airflow and velocity have a lot more to do with duct design and how fan speed, duct size, restrictions, and air mixing work together to establish comfort. Poor duct design can produce results that resemble those of oversized equipment.

Alex and Bryan also discuss:

Figuring out desired friction rate and static pressure
Changing tonnage and its effects on duct design
Load calculations
ACCA Manual T
Emergency/backup heat
Manufacturer coils and pressure drop
Rules of thumb
Principles at work in HVAC service

Use the offer code POD2019 for a great discount on Wrightsoft products at Wrightsoft.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #74 - So You Wanna Start a Business Eh? Oct 01, 2019

In this short podcast episode, Bryan explains what you need and the things you need to consider if you want to start a business in HVAC/R.

When you start a business, you need to have a healthy reserve of money already. Kalos started with $100,000, and that money went towards vans and tools needed for a GC and HVAC business. Even if you start a business with just one person and a truck, it's best to have at least $50,000 available at the start.

In the business world, you MUST care about money. Otherwise, you'll go out of business. Profit margin is important, but you must also have a healthy amount of cash readily available at all times. You must have enough cash on hand to weather a storm, and you would be wise to avoid credit card debt at all costs. At the same time, you must separate personal and business funds. You also need to have control of your pricing and know the difference between gross margin and markup.

Starting a business is also a commitment that will come with suffering. So, your spouse, kids, and mentors should be willing to help you every step of the way; a support system is extremely important. You may need to pay off the home and car debt, you may work late nights, and you may be frustrated with work at times, so the important people in your life need to be willing to support you.

Although hard independent work is necessary for HVAC work, having the right relationships is key. Knowing the right people is better than marketing in your business's early days. Be active in your community and provide excellent, friendly customer service.

Discipline, treating people well, hard work, and financial literacy are the keys to starting a business.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Dangers of Like-for-Like Tonnage Sep 26, 2019

Alex Meaney from Wrightsoft joins us to talk about Manual J and S. He also discusses how load calculations and equipment selection apply to real-world situations where contractors are tempted to replace “like-for-like.”

Load calculations have been a staple of new installations, but they are becoming important in retrofits as well. We consult Manual J when we do load calculations for residential HVAC designs. We determine where the heat loads are coming from to see how equipment can address those heat loads; in heating, we want to replace heat losses. The technicians who do load calculations also tend to get more customers and have better outcomes because they show additional care and can educate customers.

We must also be diligent and check our mistakes in calculations AFTER we work on them. In general, most load calculations will NOT determine that upsizing is the right solution.

Then, we use our Manual J calculations to use Manual S for equipment selection. When we propose solutions for retrofit installations, we should quote the customer for our recommended solution and like-for-like tonnage. You could also talk with the customers about ways to adjust the heat load; just don't tell them they're wrong, even if they are. It also helps to be straightforward about the health and dehumidification benefits of the best solution versus the like-for-like retrofit option.

Alex and Bryan also discuss:

When customers are comfortable with oversized systems
S.W.A.G. in system design
Looking at math AND customer demands
Uneducated homeowners and what they do know
Don't put thermostats in the hallway
Moisture issues, latent capacity, and dehumidification
Commissioning
"One trip, close" sales
Talking to customers about sales and quotes
"It's not time wasted; it's time invested"
Making time for load calculations and consultation

Use the offer code POD2019 for a great discount on Wrightsoft products at Wrightsoft.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Gauges, Probes & NIST #LIVE Sep 24, 2019

In this live podcast from the Castbox app, we talk about analog vs. digital, digital vs. probes, and probe vs. non-invasive testing of A/C and refrigeration. We also talk about apps and various Bluetooth tools.

Although analog gauges are old, reliable tools, digital gauges tend to be a bit more accurate than analog ones. However, the jury is still out on which one has the durability edge. Digital gauges also have batteries to worry about, whereas analog ones don't. Ultimately, the only reason to use analog gauges over digital ones is a personal preference. Probes work well with hoses, tees, and core depressors.

We still use manifolds to this day because they have charging tees and are easy to use, though you can modify probes to make them more user-friendly. Refrigerant can be left over in the hoses, and refrigerant mixing is a possibility. Probes minimize the losses of manifolds. However, non-invasive testing is another manifold-free route. The key to using non-invasive testing effectively is to become a master of the obvious and not to put too much focus on the readings alone. While it is important to know the measurements, it is even more important to use your senses to look for clear problems.

When you use tools that connect to electronics via Bluetooth, we recommend using a separate device, not your personal phone. For example, Bryan uses an iPad with a data plan.

We also discuss:

Five Pillars of HVAC Diagnosis
Favorite temperature clamps
K-type thermocouples
Mandating vs. recommending tools
Scales
Fieldpiece probes for A/C
Sporlan probes for refrigeration
Advantages and disadvantages of Testo probes
Core depressors
Checking light commercial systems with probes
Rub-outs
When readings are overrated
Best practices
"Negative" superheat and subcooling

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #73 - Ambient CO Sep 24, 2019

In this short podcast episode, Bryan talks about ambient CO. He also explains why it matters and what you do to check for it.

CO, carbon monoxide, is a colorless, odorless, and toxic gas that can result in death. It should not be confused with CO2, carbon dioxide. Although our bodies inhale oxygen and not carbon dioxide, the latter isn't toxic if it gets into our bloodstream. CO, on the other hand, displaces oxygen, which proves deadly. Carbon monoxide can also build up in your bloodstream over time, so you want to avoid repeated exposure.

In some locations, you can expect some degree of ambient CO. For example, lots of car exhaust in busy cities can lead to a low amount of carbon monoxide in the air (a few parts per million). Most CO monitors detect much higher concentrations of carbon monoxide (around 100 parts per million).

When working in a place where carbon monoxide is a concern, such as in a home with gas appliances, be sure to use your instrumentation to measure CO in an occupied space. Also, check for carbon monoxide spilling out of the unit. Don't confuse ambient CO with the carbon monoxide found in combustion analysis; they are NOT the same. Ambient CO indicates a bigger problem like backdrafting.

Unlike standard CO monitors, you will want to use a personal ambient CO monitor that can measure down to 1 part per million for YOUR safety. Again, do NOT use combustion analyzers for personal protection! You can also offer higher-quality CO monitor/alarm suggestions to your customers.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Geothermal System Considerations w/ Michael Housh Sep 19, 2019

In this podcast, Michael Housh joins us to discuss his years of experience with geothermal heat pumps and their special considerations.

"Geothermal" is a rather generic term, similar to how people say "Freon" to refer to any kind of refrigerant. Those heat pumps don't necessarily have to be underground; you can have water-source heat pumps in ponds or wells, and there are also ground-source heat pumps. The ground provides a steady temperature under many conditions, which helps heat pumps work effectively in cold climates. Like other heat pump systems, geothermal pumps come in split or package types. The pump may be either integrated with the equipment or separated from it. When the equipment is separate, multiple units can use the same loop (for example, a 10-ton loop can have five 2-ton units attached).

Michael designs geothermal systems. He uses software to design systems, particularly closed-loop systems, and load calculations play an important part in informing his designs. Many contractors use rules of thumb to help size the loops, but the only way to know what you're doing is to take load calculations, especially on water-source pumps. Undersizing loops can severely reduce the system capacity and make it hard to maintain temperature.

To keep performance up, we also need to flush heat exchangers as part of regular maintenance. However, restrictions and contamination tend to be relatively uncommon except in pump-and-dump systems. As with any type of equipment, be sure to follow the manufacturer's recommendations.

Michael and Bryan also discuss:

Patience and caring about outcomes of jobs
Water temperature and quality effects on system operation
Environmental concerns
Maximizing efficiency in geothermal systems
Geothermal sales and economic trends
Return configuration
Sharing loops
Figuring out gallons per minute and delta T
Pump-and-dump configuration
Clogged heat exchanger symptoms
Identifying problem areas
Loop temperature variations

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #72 - Vapor Diffusion Sep 17, 2019

In this short podcast episode, Bryan explains what water vapor diffusion is. He also explains why it matters to the everyday HVAC technician.

Vapor diffusion is the transfer and distribution of water vapor through a solid surface. New constructions sometimes have vapor barriers on the outside of buildings in hot, humid climates or on the inside of buildings in cold, dry climates. (Even so, vapor barriers are not 100% effective.) We are NOT referring to water or mist wicking through the buildings via capillary action; we are referring to water vapor.

Drywall, a common building material, is quite permeable and allows moist air to diffuse through it. The vapor diffuses through the drywall from the unconditioned attic to the conditioned living space. Of course, we have to focus on air sealing before anything else, but we also may need a vapor inhibitor or a means of controlling the attic dew point to prevent water vapor from moving through.

The driver that causes moisture to move into the space is surprisingly NOT relative humidity. Instead, we need to focus on the actual moisture content as a driver, and it would help us more to look at the dew point. Dew point is the key to controlling vapor diffusion. If the dew point in the unconditioned space is higher than that of the conditioned space, then you will get vapor diffusion into the conditioned space. However, if the dew points are the same in the conditioned and unconditioned spaces, then there won't be a differential that would cause vapor to move.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Difficult Customers #LIVE Sep 15, 2019

In this live conversation, we discuss some real-life situations with difficult customers. We also cover some helpful tips we learned along the way.

When Bryan started Kalos, there was one situation where a customer blamed him for lying about a customer diagnosis. So, that was how Bryan fired his first customer. However, many of us want to fire several customers, and that's when we have to look in the mirror and evaluate ourselves. When the problem truly isn't with us, we have to make a choice to say, "Sorry you feel that way," and walk away after we've tried our best.

Sometimes, customers will demand that certain procedures are done or certain systems installed. Even if we were to give in to their demands, difficult customers would still be inclined to blame us, so it's up to us to assert our boundaries and do the job correctly. We also need to stop saying that our work is "easy." When we say that work is "easy," it appears to cheapen our work in the customer's eyes.

We may encounter customers who are a bit neurotic or who want to take advantage of us. In those situations, the best thing we can do is take the customer seriously and take full responsibility for our work: carry out tests, answer questions, and solve the issue. The manufacturer may do very little to help a situation, so we must be prepared and knowledgeable.

We also discuss:

Bryan's Christmas pool heater meltdown
Commercial HVAC/R finger-pointing
Being "good with money" and how that translates to doing good business
Valuing our work
Working for family members and charging them
A ductless disaster with a nervous customer
"Calm down"
Listening productively
Setting expectations
Pricing and making a profit
Moving on from failing customer relationships
Buyer's remorse

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Refrigeraton Case Controllers w/ Sporlan Sep 12, 2019

In this podcast episode, Henry Papa from Sporlan joins us in person to talk about refrigeration case controllers on systems with common compressors. We focus on the Sporlan S3C case controller, but some of the information applies to other case controllers.

Case controllers control the conditions at each separate evaporator and are responsible for controlling defrost, discharge air temperature, and superheat. They can also monitor conditions at the evaporator, especially discharge air. In grocery, we tend to look at discharge air temperature instead of box temperature. Traditionally, we use EPRs to control a fixed evaporator pressure to control the discharge air temperature. With the S3C refrigeration case controllers, we can assess the discharge air temperature directly.

The greatest advantage of the S3C controller is that it is NOT a single centralized control. Those standalone case controllers communicate with each other but work independently. So, if one rack goes down, the rest can keep running. On traditional controls, all of the racks could go down if one goes down.

The S3C controller is also quite serviceable and connects to Bluetooth. So, you can sync the case controller display's data to your mobile device for convenient viewing. You can also control a few different functions from your device. However, you must take some time to understand the parameters, inputs, and outputs, as with any other controller. The goal is to read the manual and get comfortable with the details before working with the controllers.

Henry and Bryan also discuss:

Sporlan's podcast and training resources
Parker-Sporlan relationship
Demand defrost
Alarm systems on refrigeration case controllers
Dual-temp control
Electronic EPRs vs. traditional EPRs
Becoming "masters of the obvious"

Check out Sporlan's Chill Skills online training HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #71 - Brazing, Is Patching OK? Sep 10, 2019

In this short podcast episode, Bryan talks about brazing and soldering. He also weighs in on patching and if it is an allowable repair.

Brazing is when you use a dissimilar metal to join metals at a temperature above 842°F, and soldering occurs at temperatures below that. (Welding occurs when you use the same metal as a joining metal.) In our trade, we generally use soldering on copper plumbing and brazing on line sets. We also often call brazing alloys "solders," such as silver solder.

When making a joint, you want to have a sufficient (but not oversized) gap between the male and female surfaces of the joint. That's because the joint needs a large surface area where the solder or alloy can flow in via capillary action. Temperature is critical, as it needs to be high enough to draw the alloy into the joint, but it can't be too high.

Patching is a controversial practice, but you CAN do it. If you are going to patch a system, it's best to do it on the low side of the system at a low temperature and with minimal vibration to minimize the risk of damage. Unlike traditional brazing, patching is when you use an alloy to seal up a small crack or leak; you don't want to draw the alloy into the joint. If you decide to patch, one of the best alloys you can use is 15% silver solder. You also risk blocking the tube. If you can cut the leaking section out and patch it with a coupling, that's an even better practice.

We DON'T recommend patching on the discharge line at all.

Learn more about Refrigeration Technologies HERE.

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Grocery Refrigeration Talk #LIVE Sep 06, 2019

n this live podcast episode, we have a fun conversation talking with Nathan Orr and Kevin Compass about grocery refrigeration.

The most common types of calls are those where the machine is "not making temp." Usually, the cases can't maintain temperature due to frozen evaporator coils or backed-up drains. On low-temperature/freezer applications, we must rely on electrical or hot gas defrost to mitigate frozen coils.

Hot gas defrost is a complicated but quintessential part of low-temperature grocery refrigeration because the coils easily freeze. The discharge gas has to go to the evaporator coil and merge back into the liquid line; that gas CANNOT make its way to the suction line without causing damage, so the liquid line pressure needs to remain lower than the discharge line pressure. Kevin sometimes recommends running the fans all the time in open cases because the fans aid in the defrosting process, especially when it comes to warming the drain pan.

Another common issue that refrigeration techs encounter is starved coils. Clogged TXV screens often cause starved coils, but we don't usually replace the entire TXV in grocery refrigeration. Instead, we only replace the part that needs replacing (the screen). The same practice applies to other TXV components; we replace only the powerhead if the powerhead has an issue.

Most grocery refrigeration systems use refrigerants that are quite different from residential HVAC refrigerants. Some of the most common refrigerants are propane and carbon dioxide. However, propane is flammable, and CO2 doesn't work very well in hot climates.

Nathan, Kevin, and Bryan also discuss:

Electric vs. hot gas defrost
Walk-in boxes
Bunker cases/coffin cases
Hoarfrost
Water heaters
Defrost termination
Offsets and thermistors
Underground line sets
Charging refrigeration systems for a wide range of ambient conditions
Ammonia refrigerant

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Manual J Battle with Ed and Nathan Sep 05, 2019

Nathan Rothenberg and Ed Janowiak join Bryan to talk about the good, the bad, and the uncomfortable of ACCA Manual J, D, and S.

Manual J load calculations exist to make the BTU inputs and outputs predictable. Then, Manual S comes in to assist with equipment selection to meet the load calculations and the customer's comfort needs. Manual D is a collection of mathematical formulas that exist to help you calculate your friction rate, which is important for comfort in terms of noise in the ducts (from excessive air velocity).

Ed believes that the best way to learn Manual J is from the physical manual; several instructors will teach the calculations straight out of the book, not on computer software. The difficulty of learning Manual J is one of the manual's shortcomings. Also, while Manual D is often required by code, Manual J is not often required, meaning that technicians can get away with poor designs. A common argument against Manual J is that comfort needs also tend to vary with each customer; therefore, standardized calculations and targets may not help individual customers meet their preferences.

The typical temperature and humidity targets are 75°F at 50% relative humidity. Under those conditions, the dew point is 55°F (meeting the 20°F delta T rule of thumb), meaning that the air should remain well above the dew point. When the air remains above the dew point, the risk of a moisture problem greatly decreases, even at the expense of comfort.

Nathan, Ed, and Bryan also discuss:

Bad square-footage rules of thumb
ACCA Manual T (register placement)
Temperature and humidity effects on comfort
Oversizing equipment
Single-stage vs. two-stage equipment
Ductwork in unconditioned spaces

Check out the ACCA website at acca.org.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #70 - Is Testing Capacitors Under Load Better? Sep 03, 2019

In this short podcast episode, Bryan compares under load vs. bench capacitor testing to find out which testing method is better.

When we test the system while the motor is running, we call that testing under load. Testing under load is fairly easy; you take the voltage across the capacitor (V), amperage off the capacitor's start winding (A), and then you use the following math problem:

(A x 2652) / V

(You can also punch those numbers into the calculator on the HVAC School app.)

While you can test under load on an off system, the test will provide a more accurate picture of the operating capacitance if you perform the test while the system is running.

On a bench test, you disconnect the leads, discharge the capacitor, and test it with a capacitor tester. The tester will charge and discharge the capacitor; then, it will measure the amount of current going into and leaving the capacitor. The voltage will be lower than on a test under load.

If either of those tests yields vastly different results, then it's likely that one of your readings is incorrect; it's unlikely that the performance differs that much under load or on the bench. For example, some ammeters can read higher or lower than the true amperage value, which affects the total capacitance in the math equation.

Capacitors merely have foil plating and oil to make them work. The attraction between those forces creates a charge. Normally, these shouldn't "overheat." The plate-to-plate surface area can break down over time, leading to poor capacitance. Capacitor testing gives us a picture of the capacitance, and the state of the compressor materials could provide an explanation for the test results.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

ECM Motors A-Z w/ Eric Kaiser Aug 29, 2019

Eric Kaiser joins the podcast again, and this time, we are talking ECM motors. We discuss types, history, diagnosis, and failure prevention.

An ECM motor has a permanent magnet rotor, which means that the magnetism never deactivates. The variable frequency-driven motor is typically an induction motor, and the rotor only becomes magnetized by the stator's field. Eric describes ECM motors as three-phase AC motors, but we can control the AC pulses, resulting in oddly shaped sine waves. Those motors essentially convert the AC power to DC power and then to controlled AC power with the help of a microprocessor that measures back EMF.

ECM motors have been in the industry since the 1980s. General Electric designed them to put out a constant volume of air against a wide range of static pressures. As time has gone by, manufacturers have developed those motors to overcome a wider range of duct challenges. and to communicate with controls and display components. One of the most significant developments in ECM motor manufacturing was the constant torque motor, also known as the X13 motor. There are also constant speed and constant airflow ECM motors.

When diagnosing ECM motors, you will want to be aware of the signals. The 24v signals work similarly on constant speed and constant torque motors but differently on constant airflow motors. Sometimes, only the module has an issue, which can be separated from the motor and individually replaced quite easily.

Eric and Bryan also discuss:

Modified or pulsed sine waves
RPM as feedback
PSC vs. ECM motor efficiency
Temperature's effect on a motor's lifespan
Achieving rated static pressure
How moisture can impact motors
Overvoltage events and motor failure
Programmable speed taps
Informational resources on ECM motors

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Refrigerants to Replace R22 #Live Aug 29, 2019

In this lively discussion, representatives from Chemours and Bluon Energy join the podcast. They talk about retrofit refrigerants and what to look for in a good retrofit.

The R22 phaseout has been on the agenda for a long time due to its ozone-depleting potential. However, R-410A is also due for a phase-down in the future due to its global warming potential. While neither refrigerant will be outright banned, we will have to consider alternative retrofit refrigerants in the future, especially if reclamation rates stay low.

Almost all of the replacement options are refrigerant blends. When we deal with refrigerant blends, we have to think about temperature glide and oil return. Many of the R22 retrofit replacements are compatible with mineral oil, and that's because manufacturers add hydrocarbons, which are chemically similar to mineral oil. We try to avoid toxic (B) and flammable (2-3) refrigerants on the ASHRAE classification system, but the hydrocarbons add just a little bit of flammability to the blends (2L).

Retrofit refrigerants also behave differently in the way that they transfer heat, as refrigerants with glide may be colder in the evaporator. They may run with exceptionally cold evaporator coils, which could be an issue in climates with a high latent load. At that rate, some airflow reduction may be necessary to prevent the coil from freezing.

The Chemours and Bluon representatives, Eric Kaiser, and Bryan also discuss:

Net refrigeration effect (NRE)
Offsetting hydrocarbons
Mineral oil return and velocity issues
POE oil as a lubricant
Latent heat of vaporization
Retrofit refrigerants' heat transfer in the evaporator coil
R22 pricing expectations post-phaseout
Education and training for flammable refrigerants and blends
Benchmarking equipment
Manufacturing R22 replacements
Off-grid refrigeration

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #69 - Trap & Vent Aug 27, 2019

In this short podcast episode, Bryan discusses the importance of the trap and vent in condensate drains. He also describes some trapping and venting best practices.

Anytime you have long runs of horizontal drains, you run the risk of having a double-trap. A double-trap creates a water seal, which traps air between the two traps and prevents a system from draining properly. To avoid the complications of double-traps, you can create a proper trap at the air handler. When making a P-trap, make sure the outlet is lower than the inlet; traps need some fall. Then, you would vent it.

When creating a vent, make sure it has enough height to be higher than the pan. That way, it should take longer for the drain to overflow if it backs up. If the system has a float switch, that should be tripped before condensate can overflow from the vent. On RTUs, the cleanout is close to the unit, and the vent will go after that; RTU units can have shorter vents. Do NOT cap the vents.

Some best practices to avoid double-traps include strapping the drain properly. PVC can be especially challenging because it tends to bow and bend over time. Location can also present challenges, as we run drains underground due to the building structures and geology in Florida, which can cause backups. However, in the end, the main goal is to create a drain line that prevents air from blocking up the drain and doesn't cause property damage when it backs up.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Home IAQ w/ Jim Bergmann #Live Aug 22, 2019

In this live podcast episode, Bryan talks through real home IAQ solutions with Jim Bergmann and others. They also answer audience questions. Indoor air quality is a place where the HVAC and building science industries intersect, so it is an important topic for occupant health and comfort.

Home IAQ is much more holistic than UV lighting or ionization solutions. For example, duct leakage is one of the fundamental challenges of indoor air quality in the vein of controlled ventilation. However, some more advanced IAQ devices include particulate counters, which focus on tracking pollutants in the air and understanding how those pollutants work with relative humidity.

Some common pollutants include pollen, dust, VOCs, dander, carbon dioxide, and carbon monoxide. While most of those are bothersome and may cause comfort or minor health issues, carbon monoxide is potentially deadly. Homes that use gas appliances must have appropriate venting (and proper combustion) to keep CO out of the home.

VOCs and carbon dioxide are two IAQ villains that require ventilation to dilute them. When lots of occupants are in a space, the carbon dioxide load can get very high, and furniture, paints, and other household objects can off-gas VOCs. Ventilation also helps us control energy usage in a home.

Relative humidity is another important IAQ factor, especially when it comes to sealing ducts and controlling ventilation. Sweating is undesirable in the home, and we don't want to drive indoor temperatures below the outdoor dew point.

Bryan and Jim also discuss:

MeasureQuick duct leakage test
Return vs. supply leaks
Aeroseal
CO poisoning and testing
Building pressurization and balanced ventilation
How to use mechanical ventilation properly
CO2 sensors
Determining practical and impractical IAQ practices
Carrier Infinity controls
Reheat electricity and dehumidification
Ozone
Oversized air filters
Discussing IAQ product maintenance costs with customers

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Charge an AC Aug 22, 2019

Craig of AC Service Tech on YouTube joins Bryan on the podcast to explain how to charge an A/C unit. He also discusses his excellent new book.

Before you start charging a unit, you must know about superheat, subcooling, and other means of determining how much charge is already in the system. You must also know how the refrigeration cycle works so that you can tell if the system is operating properly. Other must-understand concepts are saturation and the pressure-temperature relationship.

To start off, you'll want to pull the disconnect on the outdoor unit. Then, get information from the homeowner and check the airflow; check the filter and examine the ductwork before turning the equipment on and using an anemometer to check airflow. When you actually begin to charge the equipment, you want to screw on your hoses clockwise and read your pressures. After you read the pressures, push the disconnect back in.

Monitor the low-side gauge and keep the saturated temperature in mind. Verify the metering device and refrigerant type. Your metering device will determine the charging method; you would use the total superheat method on fixed-orifice systems and the subcooling method on TXV systems. You use those values and compare them to the target values to determine if you are low on refrigerant or overcharged. Then, you add or remove the refrigerant accordingly to reach those targets.

Craig and Bryan also discuss:

Well-roundedness
Sliding calculators
Saturated temperature
Service valves
Superheat vs. total superheat
Frozen evaporator coils
Adding refrigerant at different points of the system
Line set length
Breaking the vacuum with refrigerant
Refrigerant Charging and Service Procedures

Check out Craig's YouTube channel HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #68 - Electromagnetism & The Aether Aug 20, 2019

In this short and nerdy science podcast, Bryan discusses how electromagnetism impacts every part of our lives. Electromagnetism refers to the movement of electrically charged particles.

From transformers to the visible light that helps us see, the movement of electrons is a critical part of our lives. For example, light is an electromagnetic wave within the visible part of the spectrum. On the more complicated side, AC motors generate a rotating magnetic field, which generates electricity. Transformers can also step down or step up voltage via two electrical coils that transfer energy via magnetism; electricity moves on the other side.

Electromagnetism deals in waves. The distance between these waves varies, and the space between each wave is called the frequency. Many radio stations nowadays rely on frequency for listeners to tune in, and you can fir several stations just between the values 88 and 108. With TV, you wouldn't even get a single channel in that range (88-108 is somewhere between channels 6 and 7 on the old VHF analog system). Frequency rates also dictate many properties of a wave.

Radio waves and microwaves are on the low-frequency side of the electromagnetic spectrum, whereas ultraviolet and gamma rays are on the high-frequency side of the spectrum. Visible light is right in the middle, and frequency helps us determine which color we see. Waves move through a vacuum and can self-propagate, but old scientists believed that waves moved through a substance called the aether.

Bryan also discusses:

Hertz scale
Electromagnetic vs. sound waves
Electrons in chemistry and physics
Atomic structure

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Moisture & Humidity Problems #Live Aug 19, 2019

In this first live podcast episode, Bryan responds to audience questions and discusses moisture and humidity issues in HVAC.

Moisture leads to other problems, including fungal growth. We often see moisture problems where the surface temperature meets the air dew point, not where hot meets cold. When the customer drives the temperature down too low, many surfaces in the home can meet the dew point and begin sweating, especially ductwork in unconditioned spaces and air handlers.

When you increase airflow, you derate the HVAC system's dehumidification. That's because the evaporator coil can't get cold enough for moisture to condensate on top of it, meaning that the moisture stays in the air. If there isn't enough dehumidification, we may end up seeing a moisture problem. These problems are especially prominent on wood and finished surfaces and can damage those severely.

When assessing a home, you also have to think about internal moisture gains, including from cooking, showering, and doing laundry. However, external moisture gains are a major concern from infiltration. Drawing poor-quality, unconditioned air from attics and the outdoors through cracks will increase those gains. You must also keep in mind that the dew point can be different throughout the house. Dew point will also be different on the ceiling compared to the floor. Some stratification occurs with height, so that can complicate matters and must be accounted for.

Bryan also covers:

Multi-stage compressors
Dew point vs. relative humidity
Infiltration, leakiness, and negative pressure
The problem with bath fans
Water in slab structures
Boot sweating
R-value and insulation in the attic
Commercial buildings with fresh air requirements
Condensate blowoff in horizontal installations
Dealing with wet insulation

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Non-Condensibles Aug 15, 2019

Eric Mele and Joe Shearer join Bryan to discuss the challenging issue of diagnosing and rectifying non-condensibles in the circuit.

Non-condensibles are gases that don't condense, including nitrogen. These are NOT moisture or contaminants, and they can be tricky to diagnose; the pressure readings will likely be normal, but the charge will actually be quite low (around 60-75% of the usual charge). These gases also don't just enter the system suddenly in significant amounts; non-condensibles typically enter the system when lots of technicians work on it, or the gases have been there all along.

One of the most telling symptoms of non-condensibles in the system is elevated head pressure and subcooling WITH flashing. (You can usually hear the flashing at the metering device if you listen.) Otherwise, the symptoms often mimic those of a metering device restriction, which is a much more common issue. The only real way to tell if you have non-condensibles is to weigh out the charge; you may recover the charge or pump down the system.

When you come across a system with non-condensibles, the customer may merely notice decreased cooling performance for an extended period. However, when a system is allowed to run with non-condensibles for a long time, there will likely be some long-term effects on your system. For example, these gases can erode the needle on a TXV.

Eric, Joe, and Bryan also discuss:

Common misdiagnoses
Metering device restrictions
How metering device type affects non-condensible symptoms
Liquid seals
Pinching off the discharge line
Copper plating on compressors
Pumping down scroll compressors (and general pump down)
Training other technicians to diagnose non-condensibles
Liquid line and filter drier restrictions
Long line sets and accessories

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #67 - Defrost Termination and Failsafe Aug 13, 2019

In this short podcast episode, Bryan quickly covers defrost termination and failsafe. He also explains what they mean in refrigeration systems.

We need to defrost evaporator coils anytime they drop below freezing (32°F, o°C). When evaporator coils have a coat of ice over them, they cannot transfer heat from the box to the refrigerant; the ice blocks the coil from the air in the box. In defrost, we add heat to the evaporator coil. We can add heat in the form of electric heat or hot gas (discharge gas); either of these can damage product if they run too long. A simple off-cycle defrost may also work on properly sized coolers and medium-temperature equipment.

We can control defrost by fixing the cycle onto a timed schedule. Unless we can use a complicated algorithm with a series of sensors, we almost never initiate defrost based on temperature. Instead, we initiate defrost based on a timed cycle. The defrost termination relies on a thermostat or control to stop the defrost, so a defrost will end early based on a temperature reading (since it will be well above freezing). After the defrost ends, there may also be a dwell time where the coil can drain its moisture before the refrigerator starts cooling again; that way, the moisture won't freeze back onto the coil when the system starts operating again.

If the defrost termination fails to kick in, we need to set a defrost end time to take the system out of defrost. We call that end time the failsafe. It is not a good idea to use the failsafe to predict the defrost cycles; it should only work in the case of emergencies.

So, to sum things up, defrost termination relies on temperature, but failsafe relies on time.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Acid and Contaminants Testing w/ John Pastorello Aug 08, 2019

John Pastorello from Refrigeration Technologies joins us to talk about testing oil and refrigerant for contamination. He also explains what each test is good for. John developed the Checkmate testing kit when he recognized a need to test reclaimed and recycled R-12 for acid and moisture.

The Checkmate method removed a small amount of refrigerant from the system for testing. The Checkmate apparatus hooks up to a refrigeration system to test the oil. You insert a tube with a rubber stopper, and you can draw refrigerant from the system when the tool pierces the rubber stopper; the method is similar to drawing blood. The kit then assesses the acid content in the refrigerant and creates a colored stain that indicates the acid content. You can use an included color chart to interpret the stain color.

Checkmate also assesses oil based on its dielectric strength; contaminants can give oil conductive properties, which the test picks up on. Unfortunately, oil breakdown can happen even when technicians use best practices, and it's commonplace on aging systems. Some tests only pick up on acid, not moisture. However, Checkmate picks up on the moisture content as well, which can be an indicator of future acid problems.

Many technicians don't perform oil testing frequently enough; if they test the refrigerant or oil at all, it's only infrequently, such as during PMs. More frequent testing could occur with easier testing methods, such as by using the Checkmate kit, and it could save HVAC system owners lots of money in the long run.

John and Bryan also discuss:

Diagnosing compressor burnout
Conductive oil
Gradual oil breakdown
Schrader core testing devices
PVE oil
Air and moisture skewing other test methods
Vapor testing
Venting exemptions for acid/moisture testing (de minimis)
Checkmate tube shelf life
Suction driers

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #66 - Water in My Tools! Aug 06, 2019

In this short podcast episode, Bryan explains what to do when you get water in your tools. (Hint: the answer is NOT to panic!)

Some technicians try not to get water in their tools at all. Depending on the climate and line of work, that may be an impossible task. In humid or coastal climates, you may deal with a lot of rain and moisture. If you work on cooling towers and boilers, you will be working with systems that rely on heat transfer through water, so you WILL encounter water.

When your tools get wet, you can't just stick them back in your toolbag and pretend that nothing happened; the tools' performance WILL suffer if you don't address the issue. If your tools get water on them, they won't dry on their own; they will corrode. At Kalos, we use microfiber cloths to clean our hand tools after they get wet. In the case of battery-powered tools, make sure you remove the battery and dry it off as best as you can. Sometimes, you can use WD-40 to help displace water.

You can also look into using degassing chambers to remove moisture from battery-free tools. These chambers look like crockpots and make it easy to pull a deep vacuum (below 500 microns) to remove moisture. (Don't put batteries or devices with refrigerant in the degassing chambers! Cell phones fall into this category, too!)

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Special Episode - The SpeedClean Story Aug 04, 2019

Mike Hardy from SpeedClean joins us to talk about how SpeedClean got started. He also explains why all contractors should consider engineered solutions.

SpeedClean emerged from the need to make coil-cleaning a better experience. Mike's philosophy is to look at the "pain points" of common tasks so that his company can develop engineered solutions to reduce the issues of those "pain points." The goal of companies like SpeedClean is to make an HVAC job more efficient to boost technician productivity and provide good value. However, Mike also believes in consumer education to promote user adoption, and he wants to make sure he conveys the benefits of SpeedClean equipment.

In the past, pressure washers were some of the only technologies available to clean coils well enough, but they often damaged the fins and led to unhappy customers. There also weren't many pump sprayers, and hoses weren't always long enough to reach the equipment. So, the CoilJet came into existence in 2007 and had a mostly positive reception on the US West Coast. Customer feedback helped Mike improve his product, and he continues to accept and integrate user feedback today.

As mini-split systems began to emerge, a need to revolutionize indoor cleaning emerged. So, SpeedClean released the Mini-Split Bib Kit to make indoor ductless cleaning easy and mess-free.

SpeedClean makes all of its products in the USA, and its company culture places a high amount of value on the employees and respects their life outside of work. There is an assembly-line-type methodology in place, and the company consistently meets demand.

Mike and Bryan also discuss:

Battery issues with the CoilJet
Negotiating labor and product costs
CoilShot evolution
User adoption and "laggards"
Systems thinking
Cleaning efficiency best practices

Learn more about SpeedClean HERE. You can check out the HVAC School and SpeedClean mini-split cleaning guide HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Crazy Filter Drier Ideas w/ Eric Mele Aug 01, 2019

Eric and Bryan talk through some non-standard ways of thinking about filter drier usage. They also discuss how to install these non-conventional filter drier ideas.

The humble filter drier helps us prevent gunk from moving throughout the refrigeration circuit with the refrigerant. That way, you protect the compressor and metering devices. Ideally, Eric would install his liquid line filter driers right before the metering device, but that's not always practical.

When you put a suction drier into a commercial refrigeration application, most people will want techs to remove it. Suction driers can drive up the compression ratio by creating a pressure drop, which is undesirable. However, Eric likes to leave the drier in the system if it won't impact the system efficiency too negatively. Replacing the suction drier is especially important in the case of compressor burnout or acid in the system. If you have an accumulator, it is best to replace it in the case of burnout; you will also want to install the suction drier near the compressor, which will help prevent or reduce accumulator damage in the case of burnout.

Above all, when you add driers to the system, you want to put them in sensibly. Their goal is to protect the system, and their sizing and placement should help them do their job. Also, DO NOT put filter driers in the discharge line! (Yes, it happens.)

Eric and Bryan also discuss:

Lennox liquid line drier placement
Factory driers
Replaceable core driers
Flares, ball valves, and bypasses
Using check valves on heat pump systems
Testing oil for acid and burnout
Undersized filter driers
Factoring material pricing into proposals and quotes
Discharge mufflers vs. filter driers

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #65 - Is R22 Becoming Illegal Jul 30, 2019

In this short podcast, Bryan discusses the recent ads and news articles claiming that homeowners are in trouble and that R22 is becoming illegal.

The R22 phaseout has been on the agenda for a long time and will finally come into effect in 2020. HCFCs have ozone-depleting potential, and it is time to look at more eco-friendly alternatives, such as R410A and R407A. The phaseout has affected prices and will cease virgin refrigerant production. However, after the phaseout period begins, R22 will NOT become illegal; you will still be able to find it in supply houses for a while.

Nevertheless, you will only have access to recovered stock, and the costs may go up as the supply depletes. It is also NOT illegal to recharge systems with R22 as long as the refrigerant charge is under 50 pounds. You also still cannot vent or import R22. Overall, the AHJ may make different rules, but the EPA is not making the refrigerant illegal.

Customers need not worry about replacing their air conditioner. There may be benefits to replacing an air conditioner, such as efficiency gains. However, there is no legal reason for customers to worry about replacing their systems. As HVAC technicians, we should focus on repairing leaks on R22 systems for customers who do not want to replace their systems. The most important thing to do is be honest with the customer; you can ease their worries about the legality of their system. However, you can still be honest about the environmental impact if the customer expresses concern about that.

Check out The Engineering Mindset's YouTube channel HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Study to Test vs. Study to Apply w/ Eric Kaiser Jul 25, 2019

My buddy Eric Kaiser from the ETS Group comes on to discuss a common problem we see in both students and techs as they study. We talk about issues with how they think about the trade and how to progress in it.

Eric noticed that people who take classes or plan to get certified tend to study just for the end test. The tests may be industry-standard, but the students and technicians don't learn to apply their knowledge; they merely learn with the goal of passing the test.

Many technicians look for courses to complete. Instead of absorbing information from articles and videos, people want their knowledge to be verified. As a society, we put so much value on completing academic programs. The truth is that learning is continuous; you don't suddenly need to stop learning once you complete a course, obtain certification, or pass a test. For schooling and study practices to be truly effective, the student or technician needs to have a mindset focused on applicable skills.

In hiring, we should focus on the applicability of an applicant's skills. Instead of using a written test or relying on a resume, a physical assessment would be a much more useful hiring tool for HVAC/R job interviews. HVAC/R jobs have significantly more difficult physical "tests" than a mere certification exam: work ethic, working under pressure, solving problems, and applying best practices. Studying for an institutional test won't help technicians or students who want to get into the field.

Eric and Bryan also discuss:

Eating healthy on the job
Certification tests
Interest-driven homeschooling vs. test-driven public schooling
Test-taking talent vs. applicable skills
Communication and customer service skills
Purging hoses and other best practices
Society's overemphasis on degrees and certificates
Benefits of traditional testing
Willingness to learn

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #64 - Diagnostic Duct Design Jul 23, 2019

Balancing complaints are common in the HVAC industry. In this short podcast, Bryan explains how diagnostic duct design solves those issues.

"Diagnostic duct design" refers to using the duct system to locate and solve a customer's comfort problems. If a couple of rooms have problems with humidity control, then the duct system could be a culprit. However, before we even touch the ducts, we should look at the space to determine if we have issues. For example, radiant gains from a window could be contributing to comfort problems, not the duct system. Airflow may also not be an issue if comfort at night is an issue. That's a matter of the equipment cycling less often at night, and we can solve that by reducing the setpoint at night.

When we look for duct issues, we want to assess the pressure. You can do very simple tests with a manometer (or a qualitative test with tissue paper under a door crack) to look for pressure imbalances, which can cause discomfort in rooms where the door is closed very often. Flow hoods are good for assessing airflow, but you can also get an airflow approximation by measuring air velocity. Make sure you're hitting your targets; then, you can check your static pressure.

Since distributed airflow is a major comfort factor, you can take the total CFM and divide it by the square footage (factoring in each room's square footage) to determine the airflow distribution. Remember: Perimeters require more airflow than the centers of rooms, and rooms with more windows will have greater radiant gains to account for.

When you can't redesign the entire duct system, use balancing dampers in oversized ducts to help balance the airflow. (Make sure the register isn't oversized, though! Try to keep the static pressure down, too.)

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Ceiling Cassettes w/ Eric Mele Jul 18, 2019

Eric really likes ceiling cassette air handlers, so much so that he put them in his own home. We discuss ceiling cassettes vs. highwall and other ductless-related topics.

A cassette air handler looks like a concentric fitting, and they are generally installed in acoustic or drop ceilings. Eric likes the comfort and easy installation. However, people who have low ceilings or dislike exposed equipment may not like ceiling cassettes as much as Eric does. Both cassettes and highwall ductless units work well in sunrooms or lanais, but Bryan has noticed that cassettes seem to provide fewer problems than highwall ductless systems in that market.

Eric has noticed substantial differences in the cleanliness of cassettes and highwall systems. He noticed that the cassettes don't get nearly as dirty as most highwalls, and highwall systems are difficult to clean. However, some of those cleanliness issues may have something to do with VOCs, pollutants, and climate.

Highwall ductless units require separate condensate pumps that require a lot of maintenance and a gravity drain. Ceiling cassettes have condensate pumps that may either run continuously or on-demand. Cassettes' condensate pumps are also easy to access for cleaning, and they are a lot quieter than the pumps on ductless units. The drain pan is also easy to pull down, though Eric has yet to need to clean his cassette's drain pan.

Although ceiling cassettes appear to have several advantages, price is not one of them; they are typically more expensive than highwall ductless units.

Eric and Bryan also discuss:

Blower wheel cleanliness issues in highwall systems
VOCs and air pollutants
Drain pitch and insulation
Gravity drains
Eric's cassette installation
New Carrier and Mitsubishi products

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #63 - I've Been Doing This 30 Years Jul 16, 2019

In this short podcast episode, Bryan breaks down the most common defense for bad practices: time in the industry. He also explains how to STOP USING IT as an excuse.

When technicians communicate with each other, especially online, they tend to justify their practices with the phrase, "I've been doing this 30 years!" What they don't realize is that their old training (and habits) don't reflect the current state of the industry and the current standards of best practices.

When technicians spend so many years in the field, they may justify bad practices by saying that they've always done a task a certain way. However, as practices evolve in the industry, time becomes less relevant as former practices fall out of favor. For example, beer-can cold is no longer an acceptable means of determining the suction line temperature.

While former practices may have helped technicians get an A/C unit to blow cold air, those practices hardly optimized performance. The goal of training nowadays is to teach technicians the best practices to optimize their customers' systems. IAQ and customer service are also much more important in our industry today.

The HVAC industry has also evolved a lot in terms of equipment, refrigerant, and oil. In the past, refrigeration systems didn't have to worry about oil conversions because we used different oils and refrigerants. Practices that we used 30 years ago are no longer applicable; technology has passed those practices by.

Nowadays, we would be best off if we paid attention to new training and best practices. We must admit what we don't know and be willing to learn more about the technology our industry relies on today. Listening to others is how we will improve, not stubbornly defending our bad practices by saying how long we've worked in the industry.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Make up air W/ Devin Skipper Jul 11, 2019

Devin Skipper comes on the podcast to give you an introduction to make-up air systems and explain their purpose. This time, we pull out all of the initials: MAU, MUA, DOAS, and MHGRV.

Make-up air is outdoor air that we bring in to replace exhausted indoor air, usually in commercial systems. We use dedicated systems to bring in humidity-controlled air to rebalance the building to a positive pressure; hotels, restaurants, and medical facilities with significant exhaust need fresh air to compensate for that exhaust and negative pressure. Unsurprisingly, design is critical for these systems, especially in humid climates.

For example, in a restaurant, fresh air must come in from an area where it can add positive pressure without too much humidity. So, exhaust devices AND make-up air units will be on the roof. Undesirable infiltration occurs through cracks and under doors and usually isn't enough to make a satisfactory difference in the building pressure. In commercial facilities, excess negative pressure can make it difficult for people to open doors, which could present a safety hazard for building occupants.

MHGRVs (modulating hot gas reheat valves) modulate discharge gas through a reheat coil. These components allow a system to keep running and maximize dehumidification without overcooling the space. When a reheat valve opens, the condenser valve closes and redirects discharge gas to the reheat coil, but they are NOT the same parts that facilitate hot gas defrost. These also keep systems from tripping on high head pressure.

Devin and Bryan also discuss:

High-latent markets and design conditions
Measuring pressure (in wc)
Excess positive pressure complications
Floor drains and negative pressure
Reheat strategies
MUA fans vs. units
MUA controls

Learn about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #62 - Impacts of Variable & Staged Compression Jul 09, 2019

In this short podcast episode, Bryan covers multi-stage or variable-speed compressors. He also explains the impacts of staged compression. Multi-stage (or variable-capacity) compressors can come in many different forms, but they all have one thing in common: they can adjust their capacities.

We typically rate equipment for its maximum capacity. However, when you vary the capacity, you get turn-up or turn-down; the refrigerant mass flow rate increases or decreases. When a unit turns down the capacity, the output decreases; the blower should also reduce its CFM output accordingly. While the compressor staging can vary, the coils and metering device stay the same, so the system must handle staged compression. We sometimes have to pay extra attention to the metering device to make sure the system operates as it should.

When we decrease the compressor capacity, the suction pressure goes up while the head pressure goes down; the pressure differential depends on the refrigerant flow. You'll also run a lower condensing temperature and higher evaporating temperature. However, if the blower adjusts its CFM output with the turn-down, these effects will be less significant. With a higher evaporator temperature, we can expect a warmer evaporator coil, which will decrease dehumidification.

Since our compression ratio will be lower, you can expect some efficiency gains during a turn-down. You can also expect lower amp draws. We can control capacity and reduce it without having to worry about short cycling.

When you turn up a compressor, as you can on some ductless systems, you can expect the opposite effects of a turn-down: higher head pressure and lower suction pressure.

Bryan also discusses:

Variable-capacity compression in ductless systems
Approach temperature
Turn-down rate on equipment

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Effects of Dewpoint on Coil TD and More MQ Updates w/ Jim B Jul 04, 2019

Jim Bergmann is back on the podcast to talk about the effects of dew point on coil TD. He also gives us a full rundown on recent MeasureQuick updates and what to expect in the future.

When you see flags in MeasureQuick, those indicate symptoms of specific problems. MeasureQuick cannot outright diagnose equipment; it can only offer variables and educate the user based on the symptoms it notices. Red flags are major faults, and yellow flags are minor faults or functions of the installation (such as long line sets), but Jim wanted to make the flags communicate information more effectively.

While Jim Bergmann worked on the sensible and latent targets, he learned more about the relationship between the dew point and coil TD. In high-humidity conditions, dropping the airflow and dew point temperature can overload the coil with humidity enough to affect the DTD by a few degrees. So, Jim had to tweak the MeasureQuick algorithm to account for those conditions.

When water is on the coil, a lot of heat transfer occurs because water has such a high specific heat value. The compressor can't keep up, and you can experience high suction pressure and high discharge pressure in high-latent conditions. The increase in suction pressure drives up the TD.

MeasureQuick has recently focused on defining targets, making the app work with new probes, and working on a cloud service that allows the user to store information, share data, and benchmark systems.

Jim and Bryan also discuss:

MeasureQuick feedback
Sensible and latent removal targets
Relative humidity and dew point
Diagnostic algorithms and variables
Communicating information through a rapidly developing app
MeasureQuick cloud service
Monetization
High airflow and duct leakage scenario

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #61 - EPR vs. CDS Valves Jul 02, 2019

Bryan talks about EPR and CDS valves. We consider both to be evaporator pressure regulators, but they really function quite differently. CDS are Sporlan components that appear to be quite similar to evaporator pressure regulators (EPRs).

EPRs go in the suction line and control the evaporator pressure. The pressure and temperature relate to each other, so the goal is to keep the evaporator from freezing by controlling the pressure. However, EPRs rely on a pressure drop across them to be able to do their job, so compression ratios will increase, impacting power consumption. We primarily see EPR valves in supermarket refrigeration on rack systems.

Electronic EPRS (EEPRS) include the Sporlan CDS valve. However, EEPRs do NOT actually measure the pressure in the evaporator coil in the same way that a standard EPR does. (However, they are evaporator flow regulators.) The pressure of an EPR is fixed via mechanical parts, but the CDS valve relies on a signal from the controller to set targets depending on the air temperature. The CDS valve can modulate via a stepper motor to maintain a certain target.

Sporlan CDS valves have a lot of benefits. For example, you can reset or adjust the CDS valve without manually adjusting it; you can easily adjust the controls. CDS valves also don't require a pressure drop because they do not rely on a mechanical process to work. If you encounter modulation issues with your CDS valves, you can power cycle them. Sporlan SORIT valves have a separate solenoid, but the stepper motor allows the CDS valves to close fully.

Overall, CDS setups can save a lot of energy and are quite easy to use because of their integration with controls. Unfortunately, they are prone to failure from power surges.

Learn more about Refrigeration Technologies HERE.

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Blends and Midpoint w/ Jim Bergmann Jun 27, 2019

Jim talks about dew point, bubble point, and midpoint in refrigerant blends. He also covers the purpose of each and why MeasureQuick displays midpoint on the gauges.

We've formerly used mostly pure refrigerants. However, as new refrigerant blends come on the scene, we have to deal with glide, which indicates that we have a range of boiling temperatures instead of a fixed boiling point. We have bubble point and dew point, which are when the refrigerant starts to boil and finishes boiling, respectively; you generally use dew point to determine the superheat and bubble point to determine the subcooling. Zeotropic refrigerants have larger glides than near-azeotropic refrigerant blends; azeotropes have no glide at all.

The midpoint is the halfway point between the bubble point and dew point in refrigerant blends. Coil temperature typically corresponds with the midpoint.

To find the midpoint of refrigerant in the condenser coil, add the dew and bubble points and divide the sum by two. The process is a bit trickier on evaporator coils. In the evaporator, you run refrigerant through the metering device and get some flash gas; when the refrigerant undergoes that change, the bubble and dew points change. As a result, the midpoint becomes a bit more weighted towards the dew point (60%).

In MeasureQuick, the temperature-pressure charts go a step above and beyond to give you the superheat, subcooling, and midpoint. The midpoint is the effective temperature of the evaporator coil, which is a critical piece of information in refrigeration systems where food products are at stake. You can also use the midpoint for coil DTD and TD.

Jim and Bryan also discuss:

R-410A and near-azeotropic refrigerants
Metering devices as reactive components
Coil temperature misconceptions and uncertainty
Pressure differentials and drops in the system
Maintaining food quality in refrigeration
MeasureQuick mathematical models and formulas

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #60 - How Cold Should it Get Inside? Jun 25, 2019

In this short podcast, Bryan discusses the ever-controversial topic of indoor temperature in the summer.

The old "20-degree rule" has come up many times, and it's time to put it to rest. Not to be confused with the 20-degree delta T rule, the 20-degree rule basically states that the home A/C system can only maintain temperatures up to 20 degrees below the outdoor temperature. For example, if the ambient temperature is 95°F, the indoor temperature should be able to stay around 75°F.

However, that differential is not a fixed value. For example, if the outdoor temperature were to reach 105°F when the unit has 95° design conditions, the system capacity would decrease. The unit will not perform as expected, putting out fewer BTUs than it would under design conditions. Design conditions also account for latent load; that is why A/C systems in the arid Southwest USA can keep up with much hotter ambient temperatures than those in humid Florida. In Florida, we design for a higher latent load and must avoid oversizing; these conditions take away from designed equipment's sensible capacity. Correct sizing prevents short cycles and keeps humidity at bay.

As it gets colder outside, an HVAC system will also have a lower heating capacity. Heat is a function of the temperature differential; heat may enter or leave the home via conduction (through walls) or radiation (through windows), and it will attempt to reach equilibrium. The only way to get around these heat gains and losses is to check the expanded performance data and perform load calculations (Manual J) to design the ideal system. You must design the equipment to maintain a specific differential under a standard set of conditions.

Learn more about Refrigeration Technologies HERE.

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Suction Pressure in Market Refrigeration Jun 20, 2019

Nathan Orr is back. In this podcast, we discuss suction pressure in market refrigeration and how rack techs think about it differently than HVAC.

On parallel rack systems, suction temperature helps technicians determine the cooling load and how to get that to temperature. You run your discharge air temperature a bit lower than the product temperature. Your suction pressure also lets you know if your coil is reaching the correct temperature. Coil temp, also called suction saturation temperature (SST), is a vital metric for rack system operation. Lower suction pressure indicates a lower coil temperature or SST.

The evaporator pressure regulating valves help control the evaporator pressure to manipulate the evaporator temperature. Compressors also help drive suction pressure, which is critical because racks may have several of them.

When you walk into a rack room, you may see around five compressors. All suction lines tie into a single suction header (same goes for discharge and liquid lines and headers). Typically, the rack is constructed to maintain the SST even if a compressor goes down. When the SST no longer maintains, there will be a "rack down" call.

If a case is not keeping temperature without an apparent rack issue, you want to take your superheat at the case to get an idea of the suction. The superheat, SST, and suction pressure will be your key indicators of problems, including defrost issues, clogged TXV strainers, and airflow problems. Overall, rack refrigeration systems work best with high suction pressure and low liquid pressure.

Nathan and Bryan also discuss:

TD in rack refrigeration
Setting EPR valves
Rack sizing
"Rack down" calls
Troubleshooting produce cases
Holdback valves
Frozen cases
Using dry steam

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #59 - Low Static Can Be Bad Jun 18, 2019

In this short podcast episode, Bryan explains why low static pressure may be bad. He also discusses the other indicators of airflow.

When you look at fan charts, you'll notice that there will be an available static value. When you measure static pressure, you're looking for the pressure applied against the sides of the duct, not forward through the duct (velocity). Low static pressure is generally desirable because it indicates that the fan motor isn't working as hard to move the appropriate amount of air. In that same vein, slightly oversized ducts may be okay for these uses as well.

However, low static is not always a good thing; you can only use it as an indicator for performance in standard operation. If the system is moving less air, then the static definitely WILL be lower. In normal operation, that may not be the case. You may also not be moving enough air, which can indicate an issue with the blower.

In other words, you must be sure that the airflow is correct through other means than static pressure readings. Airflow has so many indicators, and using just one won't suffice. You'll also have to use your senses to listen for issues and familiarize yourself with the system operation; determining system airflow requires a multi-pronged approach.

Bryan also discusses:

Duct vs. face velocity
Variable-speed equipment
Thermostat calls and their effect on the blower

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Can a Residential Tech Transition to Market Refrigeration? Jun 13, 2019

Nathan and Bryan have a rollicking conversation about Nathan's transition from residential HVAC to market refrigeration. Nathan also covers what he has learned along the way. Hopefully, his experiences can help you decide if moving to market refrigeration may work for you.

Before Nathan went into market refrigeration, he handled problem customers and repeat issues on the residential HVAC side. He worked on zoning systems and mini-splits quite often. Even in that time, he did minor work on supermarket projects if the team needed an extra person. Market refrigeration projects require full scopes of work and time constraints, complicate the transition from residential HVAC work.

Market refrigeration primarily deals with rack systems. Rack refrigeration systems are different from residential HVAC systems because they require less of an understanding of heat transfer; refrigeration techs need more mechanical knowledge and may rely on many rules of thumb. Tactile skills are essential for refrigeration, but an understanding of the scientific fundamentals is less important.

Although there are plenty of opportunities for increased profits in market refrigeration, the losses are also fast and harsh. The customer relationship is also perhaps even more important in market refrigeration because the service (and customer) options tend to be more limited. You may also expect to sacrifice more time due to the urgency of supermarket work. While you don't have to work yourself to death, you should definitely expect to have less time and to reschedule plans quite often if you make the transition to market refrigeration.

Nathan and Bryan also discuss:

Sight glasses vs. subcooling
Cost of mistakes
Acceptable vs. unacceptable outcomes for customers
Overhiring vs. underhiring
Rack replacement
Difference in standards
Replacing TXV parts
Motors in refrigeration
Hands-on skills and relevant professions
Good and bad practices in refrigeration
Working hours

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #58 - A Fair Price Jun 11, 2019

In this short podcast episode, Bryan covers pricing for HVAC/R parts and services; he explains how to come up with a fair price.

To be able to price fairly, we need to understand what value and sacrifice look like. In the HVAC industry, we value hard work and growth in a way that some other people don't. We provide parts and labor and sell those in the free market, so we can control how much we charge for those.

The price of a part means NOTHING in the industry. Instead, we primarily set prices based on labor, which is much more value-based. The customer has the right to accept or decline the service based on the price, and some customers WILL decline the service based on price. In the end, the customers can choose to agree or disagree with your opinion of value.

Some people will object to the idea that customers know what a price is truly worth. However, Bryan is of the school of thought that almost no price is "unfair." As long as the customers have different companies to choose from, they have the right to shop around and pick a price that works for them. It is not the responsibility of the company to reduce its prices to attract customers. Remember, you need to think about pricing in terms of value and honesty; customers who also value your work will pay for it. If your services are superior, there is nothing wrong with keeping your prices high to reflect the value of your work.

Bryan also covers:

Learning about economics
Supply and demand vs. price gouging
Reinvesting in the business
Sales vs. technical excellence
Markup vs. gross margin

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Preventing and Mitigating Legionnaires' disease Jun 06, 2019

We talk with chemical and cleaning expert Ray Field on Legionnaires' disease. We discuss what it is, its history, and what we can do to prevent it proactively.

Cooling towers host all kinds of microorganisms, including harmful bacteria like Legionella. Legionella is a natural bacteria that you can find in bodies of freshwater, including lakes, but it was discovered relatively recently, in the 1970s. We become susceptible to Legionnaires' disease when we inhale droplets that contain Legionella. Legionnaires' disease causes pneumonia-like symptoms and is potentially fatal. Cooling towers, unfortunately, provide perfect conditions for Legionella to survive and aerosolize. Decorative fountains and evaporative coolers also provide ideal conditions for Legionella to grow and thrive.

Unsurprisingly, cleaning with special attention to microbe control helps mitigate Legionella bacteria growth. Bleach and anti-microbial peroxide help keep the water clean, but the bulk water is just one part of the system. When Legionella-filled water sprays beyond the tower, slime and water accumulations may also harbor Legionella.

Inspecting and cleaning towers monthly are the best practices. Vacuum the basin and descale the tower each time you clean the tower; when you clean slime, deposits, and scale, you give Legionella fewer places to hide. You can also disinfect the tower exterior. Pressure-washing works well as a starting point and can be followed up with chemical technology. Overall, the key to preventing Legionnaires' disease is proactivity; safety begins with a regular maintenance regimen, use of proper PPE, and thorough training for cleaning procedures.

Ray and Bryan also discuss:

Legionella growth assistance
History of Legionnaires' disease
Ideal Legionella growth conditions
ASHRAE Standard 188P
Fill deposits
Goodway products to combat Legionella
Legionella testing and CDC guidelines

Learn more about Goodway HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #57 - Ductless Cleaning Guide Jun 04, 2019

In this short podcast episode, Bryan covers ductless or mini-split cleaning. He collaborated with SpeedClean to map out this procedure and write a guide, which you can read HERE.

Cleaning is ultimately a maintenance procedure, so one of the main goals is to keep energy efficiency high (watts per BTU). You can test energy efficiency by using two psychrometers: one up top and one going into the vanes. You can check the delta T and fan charts to determine the performance. Overall, you clean ductless units to improve system performance, equipment longevity, and indoor air quality. Be clean; wear shoe covers and put down drop cloths in the customer's home.

First, you confirm the system operation and do a visual/auditory inspection. Then, make sure you have all of the PPE you need, especially goggles and gloves.

Usually, you will clean the evaporator, blower wheel, air filters, and condenser coil. Pay attention to the drain and condensate pump as well; they can clog and negatively affect your system.

We often use the bib kit indoors. When you use one of those bib kits, you can clean the evaporator (and sometimes the blower wheel) in place. The bib goes over the ductless unit, so cleaning is seamless and shouldn't make a mess as it runs off into a bucket. We recommend using a pump sprayer like the SpeedClean CoilJet; bringing a hose in can cause a mess and is impractical.

When you've finished cleaning, make sure you let everything dry completely. We like to keep plenty of rags on us so that we can wipe everything down. After you think everything has dried, you can test the system. (It's a good idea to keep the bib on at first to prevent the unit from splashing liquid everywhere.)

Learn more about SpeedClean HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

A Peek Behind The Curtain w/ Andrew Greaves May 30, 2019

Andrew Greaves comes on the podcast to give us a sneak peek into the life of a tool manufacturer. Andrew has worked in the field for a long time and has recently begun working for NAVAC. He currently works as a regional manager who oversees operations in 24 states; his main task is to establish a nationwide distribution network for NAVAC products.

Andrew recognizes the need for communication between wholesalers/manufacturers and technicians, especially in the areas of education and product demand. To bridge that gap, the sales representatives act as middlemen between manufacturers and consumers. Representatives must know what the consumer demand looks like so that they can effectively sell products that technicians want to buy. Effective representatives must also understand their market and have a grasp on the training necessary to use the products they sell.

The ultimate way to connect the manufacturer to the user is through training. Andrew working for NAVAC is a promising move for the industry; he knows how techs use tools in the field and what they need to succeed in their work. When people bring field experience to the manufacturing world, they can meet technicians' on-the-job needs while keeping their businesses afloat. When these businesses stay in the game, they can continue to provide quality tools that truly help technicians.

Andrew and Bryan also discuss:

Taking a technical background to sales
Misunderstandings between wholesalers and technicians
Stigmas against sales reps
Production of good tools
Analyzing the market
Combatting the "BS" sales response
Commitment and sacrifice in the HVAC industry
Viable career paths beyond the field
Putting out online training and content to make a name for yourself

Check out NAVAC at navacglobal.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #56 - Bypass Factor May 28, 2019

In this short podcast episode, Bryan covers the bypass factor in airflow and psychrometrics. He also explains why it matters to techs.

The bypass factor is a ratio: you take the difference between the evaporator coil temperature and outlet air temperature as compared to the inlet. In other words, you find the difference between your TD and delta T.

When air moves over the coil, only some of it contacts the coil's surface. Therefore, only some molecules will become the same temperature as the coil. Other air molecules will bypass the coil, which typically happens when coils have a lower surface area. Evaporators have fins to increase the coil surface area, which helps those air molecules bump into the coil and transfer their heat. Without those fins, your performance will suffer; the saturated suction temperature will drop, and your temperature split will be lower, indicating a higher bypass factor. We want that air to have MORE contact time with the coil; therefore, we want a LOWER bypass factor.

However, when we account for total enthalpy change across the evaporator coil, we also have to look at the latent content; that topic can get complicated and theoretical very quickly, so we avoid that discussion for the sake of simplicity.

The bypass factor also accounts for contact time, which is the amount of time needed for the air molecules to transfer their heat to the refrigerant. You can reduce air velocity to increase the contact time, which is the inverse of the bypass factor.

Bryan also covers:

Coil types and impacts on bypass
Impacts of coil size on dehumidification
CFM adjustments with varied coil sizes
Sensible heat ratios (SHR) and installation considerations

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Women in HVAC/R May 23, 2019

Colleen Keyworth from Women in HVAC/R comes on the podcast to talk about the importance of getting women excited about our trade.

While many women take up administrative roles in HVAC/R companies, very few women work in the field. Schools don't tend to market trade schools to women (or in general), so we can attribute part of the gender gap to how high schools present career options to people. Women in HVAC/R as an organization helps educate young women about career options in the trades. Colleen also has a very positive view of the industry and the values that contractors tend to promote.

In general, women just want to be treated the same as men; women who go for HVAC careers want to be part of the rule, not seen as the exception. Colleen believes that female techs don't require any special considerations as long as the company culture is already intact. To get women interested in the field and set them up for success, we just need to be clear about expectations and what the job entails; the heavy lifting is only a small part of the job, and the physical disadvantage sometimes gets overblown.

The pillars of Women in HVAC/R are membership, sponsorship, mentorship, ambassador programs, and networking. Memberships are for all people who have a common goal of promoting a greater female presence in the HVAC/R industry, regardless of gender. The ambassador program is what really focuses on reaching out to young women in high schools.

Colleen and Bryan also discuss:

Women's success in sales
How women overcome the physical strength gap
Support of men in the HVAC industry
Non-inclusive environments in the past
Generational differences

Learn more about Women in HVAC/R and consider becoming a member at womeninhvacr.org/.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #55 - Vacuum Pump Maintenance May 21, 2019

In this short podcast episode, Bryan explains the ins and outs of vacuum pump maintenance, a critical component of evacuation.

The most basic part of vacuum pump maintenance is changing out your vacuum pump oil. This practice should happen very often. At a minimum, you should replace your vacuum pump oil weekly; in very wet or contaminated systems, you may need to replace it multiple times during the same job! When moisture gets into the vacuum pump oil, it can wear out your vacuum pump well before its time should be up. So, most of the maintenance practices exist to reduce the risk of moisture damage.

Good-quality pumps can last for several years with the proper attention to oil management. If you can cap the outlet of the pump, then that's a good idea to prevent moisture from getting to the oil. You'll also benefit from leaving your gas ballast open until you get down to the 500-micron range.

You'll want to keep your vacuum pump in a place where it won't be jostled or thrown around. It's an expensive piece of machinery that shouldn't take too much abuse. Store your pump in an accessible but secure location.

When it comes to evacuation, be sure to use dedicated hoses. Dedicated hoses don't hold moisture because they are vinyl; you can make them even safer by keeping your hoses capped off. All pump ports should also be capped when they are not directly in use.

Test the pump periodically; it should pull down to under 50 microns. If not, the pump will have a hard time evacuating adequately. If you want to test your micron gauge on the pump, keep in mind that the micron gauge will leak.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Airflow Testing as a Customer Service Tool May 16, 2019

David Holt from NCI comes on the podcast to talk about airflow testing and its importance as a customer service tool for the HVAC trade.

Charging and airflow are closely linked. Even though the charge may be correct, the system can't operate correctly if the airflow is off. For example, we can only get the most latent heat removal in humid climates if we run lower fan speeds. To get the right balance, we need contractors and technicians to be educated on airflow so that they can make the correct adjustments. (Remember your ABCs: Airflow Before Charging.)

Testing airflow may require you to make adjustments to the system, such as installing test ports. You need to be able to measure static pressure in your system, and you can tell if previous contractors have done it or not by the presence (or absence) of test ports. On the customer service side, pointing out the lack of test ports or other testing evidence allows the customer to discredit the previous contractor; you don't have to be negative about someone else to get customers to trust your company over the others. Testing also keeps your installers honest; almost everybody will realize that their company has made mistakes after they test the system airflow.

One of the best ways to educate customers is to speak in terms they understand. For example, David compares static pressure to blood pressure in our bodies. In that same vein, we'd be committing malpractice if we refused to test airflow or disclose our test results.

David and Bryan also discuss:

Qualitative vs. quantitative data
Low-bid contractors
System airflow impacts on combustion
How to measure static pressure
Pressure drops across coils and filters
Variable speed motors
Sales vs. technical excellence
Premium pricing and earning what you're worth

Check out NCI at hvactoday.com. Also, check out the AirMaxx Lite app.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #54 - Sunk May 14, 2019

In this short podcast episode, Bryan covers the basics of sunk costs. He explains what they are and what they mean for you and HVAC businesses.

Sunk costs are costs to decisions that have been made in the past. You've "sunken" money, time, or effort into a decision. Let's say you invest in tools; after you make that purchase, the cost of the tools will become a sunk cost. The cost merely occurred in the past.

It is a good idea to reflect on these costs as something that is already over; you can reflect on these costs as a lesson for how you invest money in the future. It is not particularly helpful to view sunk costs as a past cost that keeps you down.

The same mindset applies to employment. Someone may hire you, and you may realize that the job is exactly what you thought it was; other times, the job may be a poor fit. If you can look back and say, "If I could redo the choice to take this job with what I now know about it, I wouldn't take it," then you may want to consider finding another job. In other words, sunk costs allow you to reflect; they aren't a specific category of costs like overhead.

Very few situations require us to take pause and reject attachment to sunk costs. In short, viewing past decisions in terms of sunk costs can help us make logical decisions about buying tools, hiring employees, and accepting employment offers. Sunk costs factor your experiences into decision-making, but we have the choice to cling to those costs or detach ourselves from them.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Residential Air Balancing & Flow Hoods May 09, 2019

Steve Rogers from the Energy Conservatory comes on the podcast to talk about residential air balancing and flow hood accuracy.

Residential air balancing is important because it contributes to comfort in the home. To achieve the most comfort possible, we need to know where the air is going inside the home. For example, some rooms may be more conditioned than others, even if they may need less conditioning than the under-conditioned rooms. A flow hood can give us some data about the airflow in the ductwork; there are cases where dampers may be closed, which blocks airflow and contributes to customer discomfort.

Load calculations can only help so much. Systems require flexibility because air distribution can vary across seasons or throughout the day. HVAC systems won't always perform under design conditions, so it's a good idea to think about customer comfort above Manual J or Manual D calculations.

Flow hoods are some of the best tools for residential air balancing; they can tell you where there is flow and where there is not. However, flow hoods are expensive and may not be completely accurate if they haven't been calibrated correctly. Many manufacturers use a single supply register configuration or wind tunnel for calibration. Many flow hoods use a pitot array, which is a grid that attaches to a manometer. Others use the RPM of an impeller to measure the flow; they also compensate for resistance. Some hoods also use vane anemometer technology. You can typically determine the insertion losses by looking at the hole size.

Steve and Bryan also discuss:

Pressure vs. velocity
Air handler location
Load calculation (Manual J)
Balancing dampers
Anemometers vs. flow hoods
Insertion loss
Flow conditioning
Building envelope construction
TrueFlow Grid
Accuracy questions about flow hoods

Check out THIS webinar with Steve and Bill Spohn.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #53 - Brazing Steel May 07, 2019

In this short podcast episode, Bryan covers the unique practices of brazing steel. He also explains how it differs from brazing copper.

Brazing steel appears to be a rather uncommon practice in the HVAC industry. However, we actually do braze steel when we braze in compressors. Many compressors have copper-plated steel stubs; only the outer coating is copper, and if you burn through it, you'll reach the steel. However, steel requires a different fluxing agent than copper-to-copper or copper-to-brass brazing; you can't use a 15% silver-phosphorus rod because phosphorus doesn't react well with steel.

Instead, you will need a high-silver rod WITHOUT phosphorus when brazing steel to steel, copper, or brass. We recommend using a separate fluxing agent or flux-coated rods. However, high-silver rods are expensive and REQUIRE flux. When working with a compressor with copper-plated steel stubs, try to get all the solder off with heat.

When working with steel, you must keep in mind that it has a higher melting temperature and lower thermal conductivity. In other words, you can apply more heat to steel without it melting, but the heat doesn't transfer to steel as easily as it does to copper. You'll want to move your torch around more and pay more attention to the tip you use. Even though the thermal properties differ from copper, you're still aiming to get the steel to a dark cherry red color, about 1200 degrees Fahrenheit.

Remember, you also want to protect any other components that will come into contact with the heat. You can use a wet rag or Refrigeration Technologies WetRag, which works great as a heat-blocking putty.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Leak Detection w/ John Pastorello May 02, 2019

John Pastorello from Refrigeration Technologies is back on the podcast to talk about leak detection procedures from start to finish.

Big Blu was what started the Refrigeration Technologies empire. John developed Big Blu to create a bubble leak detector with a higher sensitivity to leaks than any other bubble test solution on the market. Big Blu differs from other leak detection solutions because it detects gas leakage down to 0.65 ounces per year, putting it on the same level as some of the best electronic leak detectors.

One of the most common misconceptions in our industry is that systems don't leak at all. That is simply not true; all systems leak to some extent. When we check for leaks, we want to check for unacceptable leak rates; detectors will normally reveal when a leak occurs at an unacceptable rate.

Most of the leaks we check for are standing leaks, which we pinpoint when the system is off. We also have pressure-dependent leaks, temperature-dependent leaks, and vibration-dependent leaks. Those leaks vary with system operation, and you may even hear the leaks when the system is under a certain set of conditions.

Overall, you want to use your senses to look for oil spots, listen for hisses, and feel for oil residue before using an electronic leak detector. If you get a hit, pull out the Big Blu. When using soap bubbles, also be sure to use a mirror and light source to look all the way around a joint.

John and Bryan also discuss:

Pressure distribution in the compressor
Leak rate and molecule size
Leaky valves and mechanical issues
Cumulative micro-leaks
Losing refrigerant from hooking up gauges repeatedly
Leak detector sensitivity and calibration
Efficiency during leak detection
Oil spotting
Evolution of leak detectors
Checking for leaks on furnaces
Testing leak detectors

Learn more about Refrigeration Technologies HERE. You can also find their FREE Leak Detection Manual HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE

Short #52 - Enthalpy Apr 30, 2019

In this short podcast, Bryan dives into enthalpy. He explains what it is and how we see it at work in the HVAC/R systems we service daily.

Enthalpy is a fancy word for the total heat energy within a substance. Don't confuse it with entropy, which is the disorganization of energy in a system. We measure enthalpy in energy per mass unit, such as BTUs per pound. Enthalpy combines both the sensible and latent heat capacity; for example, it may represent the energy that it takes to evaporate the water contained in the air. (Water vapor is always present in the air, not just at boiling. Evaporation also occurs at many temperatures below the boiling point.) So, the more water vapor in the air, the more enthalpy there is.

Believe it or not, water vapor is less dense than dry air. So, we can't equate thermal mass to density. Air with a heavy concentration of water vapor has lots of latent heat trapped inside the water vapor. However, we won't recognize that heat until that water vapor condenses to a liquid at the dew point, such as on a cold evaporator coil. Relative humidity measures the moisture in the air as a ratio. An RH value of 100% indicates that the air is at saturation. That is also the point when the dry-bulb and wet-bulb temperatures will be the same.

Overall, we don't care very much about enthalpy values on their own; in HVAC work, we want to calculate changes in enthalpy across parts of the system. We care about changes over the coil, such as drops over the cooling coil. Psychrometers come in handy when you are trying to look for trends in the enthalpy content of the system.

Learn more about Refrigeration Technologies HERE.

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Hybrid Boiler Plants w/ Jim Devlin Apr 25, 2019

Jim Devlin from Weil-McLain joins us to talk about high-efficiency and cast-iron boilers. He also explains how to use them together in a "hybrid" configuration to serve your customers.

Cast-iron boilers are standard-efficiency boilers. These boilers are "standard-efficiency" because they have higher return water temperatures; you typically measure about 330 degrees in the flue. Conversely, high-efficiency boilers have much lower return water temperatures, only around 180-190 degrees in the flue. The goal of a high-efficiency boiler is to get more BTUs out of the fuel, so your flue gases will be cooler. However, the standard boiler can be better for thermal transfer and gives us more leeway for our flue temperatures.

Hybrid boiler plants aim to eliminate inefficiencies by using cast-iron and high-efficiency boilers together. These hybrid configurations usually exist in older constructions, but you also see them in new constructions with dual-fuel burner systems or where high-efficiency boilers won't have a good value on their own. You will often see a greater ROI on systems that use cast-iron and high-efficiency boilers together than on systems with multiple high-efficiency boilers. Hybrid configurations usually set up dissimilar boilers in series with a primary-secondary loop. The controls usually use sensors and 1-10v DC output signals, so these controls can modulate the burners.

Many people make mistakes when piping these boilers; they don't understand the parallel positioning of the tees. When installers make these mistakes, the boilers lose efficiency. Jim recommends drawing out the piping to avoid making those errors.

Jim and Bryan also discuss:

Sulfuric acid and condensate
Boiler metals
Dual-fuel burner systems
Boiler controls
Hybrid vs. Combi-boilers
Comparing utility reports and checking ROI
Energy savings on cast-iron boilers
Heat exchangers
Future geothermal and solar hybrid systems

Visit weil-mclain.com to learn more.

Learn more about Refrigeration Technologies HERE.

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Short #51 - Separate Gauges Apr 23, 2019

Do you need different gauges for each refrigerant? In today's short podcast, we discuss the answer to this common HVAC question.

When we first started using R-410A, many people warned us that we'd have to use a separate set of gauges when working on R-410A systems. That's because R-410A systems use POE oils, not mineral oil, and they are not compatible. While it is true that R-22 and R-410A systems use different oils, there is no need to worry about using separate gauges for each type of system. Actually, some manufacturers recommend using a little bit of POE oil in mineral oil systems.

What you cannot do, however, is mix the refrigerants themselves. Many of the gauge hoses have quick disconnects, which cause some confusion regarding the de minimis rule. (The de minimis rule permits tiny refrigerant losses from regular servicing, and de minimis DOES protect us.) However, we aim to keep our hoses clear anyway. We do that by bleeding liquid refrigerant back into the suction line after servicing.

So, the real concern doesn't lie in which refrigerant we use with our gauges. The real issue is about taking steps to avoid contamination of the entire system and stay in compliance with EPA standards. Mixing POE and mineral oil does not negatively affect a refrigeration system; however, moisture does pose a threat to POE oil. Again, the core issue deals with best practices: flushing and purging hoses, minimizing the risk of hydrostatic pressure, avoiding venting, and avoiding mixing refrigerants.

Of course, you don't have to worry about any of these problems and practices if you check the charge without gauges. Using probes is an easy way to get good measurements without worrying about contamination

Learn more about Refrigeration Technologies HERE.

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Parking BTUs with Buffer Tanks (Part 2) Apr 19, 2019

In this two-part interview, Moe Hirsch goes deep and wide on buffer tanks and strategies for "parking" BTUs in hydronic systems.

Systems with a high domestic hot water load can also benefit from a buffer tank. You can pipe the domestic hot water tank as its own zone and step down the rest of the structure. However, there will be some standby losses for a tradeoff greater capacity. You also cannot use the buffer tank as an air eliminator or separator; they work only for BTU parking.

Contrary to popular belief, buffer tanks do NOT prevent flue gas condensation. If the buffer tank reaches 120-130 degrees, then it may prevent flue gas condensation via the flywheel effect. Flue gas condensation on boiler systems has to do with excess air, combustion, and run cycle length.

Moe and Bryan also discuss:

Water storage temperature
Using a biomass boiler as a backup
Stratification: tall tanks vs. wide tanks
Cycle times and mathematical formulas
Outdoor reset targets
Boiler startup conditions
Manual reset high limit

Parking BTUs with Buffer Tanks (Part 1) Apr 18, 2019

In this two-part interview, Moe Hirsch goes deep and wide on buffer tanks and strategies for "parking" BTUs in hydronic systems.

When we use boilers, we want to use a heat sink to "park" BTUs in a buffer tank so that we can temporarily store extra heat and avoid short cycling through load matching. However, few boilers have an actual buffer tank; many systems have a means of creating a buffer, though. Buffer tanks are good for parking BTUs in systems with zones and microzones that require varied heating needs. The amount of BTUs you store depends on the temperature difference between the beginning and end of the tank and the water quantity.

Moe and Bryan also discuss:

Pressure tanks
Variable frequency drives
Getting extra BTUs
Snowmelt systems and Combi-boilers
Two-pipe and four-pipe configurations
Creating and positioning buffer tanks
Hydraulic and air separation
Reverse indirect water heaters
Parking BTUs in concrete
Dirt and magnetic separation

Short #50 - Oil Apr 16, 2019

In today's short podcast episode, Bryan covers the basics of refrigerant oil in HVAC/R systems. He also discusses what technicians can do to maintain oil systems.

Oil lubricates the moving parts of the compressor. So, oil moves with the refrigerant and lubricates the parts as the refrigerant moves through the compressor. Unfortunately, oil can migrate to other parts of the circuit when it's not supposed to.

Flooding occurs when liquid refrigerant enters the compressor crankcase, and slugging occurs when liquid gets into the compressor head. When either of those happens, they can eject oil from the system. When a system has insufficient oil, the compressor's moving parts can heat up and wear out quickly. We can use an array of preventative strategies to keep oil in the system and reduce the risk of compressor damage.

We want to keep our discharge lines below 225 degrees to prevent oil (or lubricant) breakdown. To prevent the compressor from overheating, we want to look at mass flow rates and compression ratios. We should also make cleanliness a priority, as dirty components can increase the compression ratio.

Oil has evolved with refrigerants. We largely used mineral oil with HCFCs like R-22, but we have begun using POE oil with HFC refrigerants like R-410a. Newer HFCs are generally NOT miscible with mineral oil, but we must be careful with POE and PVE refrigerants because they are hygroscopic. These oils break down via hydrolysis when they react with moisture, and they become acidic. So, we need to keep POE and PVE systems dry to prevent damage.

Bryan also covers:

Hard shut off TXVs
Pump down cycles
Oil return
Viscosity
Oil velocity and pipe design
Miscibility
AB oil

Check out our oil article HERE.

Learn more about Refrigeration Technologies HERE.

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Recovery Best Practices w/ NAVAC Apr 11, 2019

In today's podcast, Kevan Mayer from NAVAC comes talks about recovery and ways to make it work better and more safely for you.

Recovering refrigerant is better for the environment and safer for us. When designing recovery equipment, NAVAC's goal is to limit the gases we put into the atmosphere and leave the planet in better shape than we gound it. Recovery also ensures that refrigerants for phased-out refrigerants remain available.

Tanks require vacuums of at least 1000 microns, if not deeper. We also need to remember what the previous tank contents were to make sure that we only fill the tank with those refrigerants and oils. You absolutely DO NOT want to mix refrigerants. Tanks should always be up-to-date and must be certified every 5 years.

When recovering refrigerant, one of the best practices is to use a filter-drier to filter out moisture and contaminants. Reducing moisture and contamination will increase the life of your recovery machine. However, a filter-drier will not restore refrigerant back to the highest purity standards.

The speed of your recovery will depend on your vacuum, recovery machine, hose sizing, and core removal. You can also raise pressure by turning the fan on. The goal to produce speedy recoveries is to reduce tank pressure and increase system pressure.

When it comes to filling the tanks, we must pay attention to the tare weight and water capacity. However, we must understand that the water capacity is NOT the same as refrigerant capacity. We need to do a little bit of math to fill our tanks safely.

Kevan and Bryan also discuss:

Evacuation vs. recovery
Reclaim company tank-handling protocols
Refrigerant mixing costs/consequences
Using recovered refrigerant legally
Compression ratio
Hose sizing and manifolds
Push-pull method
The 80% rule
NRDD recovery machine

Learn more about NAVAC tools at navacglobal.com.

Learn more about Refrigeration Technologies HERE.

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Short #49 - VA vs. Watts Apr 09, 2019

In this short podcast episode, Bryan covers the difference between volt-amps (VA) and watts when we take electrical measurements.

We usually use VA to rate transformers, but we use watts for other electrical ratings. Even though you can multiply volts by amps to get wattage, the difference between VA and watts has to do with the power factor. Power factor is the ratio of apparent to active power. VA is the apparent power, and watts is active power. The difference between volt-amps and watts is called KVAR (kilovolt-amps reactive). The reactive volt-amps are not effective; you can compare them to the foam on a beer (if the entire beer is the VA, the watts are the actual beer).

When we look at motors, we want to know how much actual work that motor is doing. That's why motor ratings are in watts or horsepower; the utility company is also probably going to charge you in watts. However, we want to measure transformers in VA because we are more concerned about the exchange of current, not necessarily the work to be performed. (Smaller transformers use VA ratings, while larger transformers have KVA ratings.)

Our goal is to have a power factor of 1, as that indicates a minimal amount of ineffective reactive power. In those cases, our motors and other electrical components will be working efficiently. There is also less unnecessary heat when our systems have a power factor of 1. When our systems get out of whack, we may have to do power factor correction.

Learn more about Refrigeration Technologies HERE.

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System Oversizing & Independent Consulting w/ Genry Garcia Apr 04, 2019

In this episode, I talk with tech, contractor, and consultant Genry Garcia. He tells us about his experiences with independent consulting and helping other contractors in South Florida.

A chunk of Genry's work deals with independent consulting, which primarily focuses on helping other HVAC businesses and contractors instead of customers. South Florida has unique climate considerations, and Genry focuses on improving workmanship in a way that works well with the climate. Diagnosis remains important in Genry's work, as he needs to find and solve issues with HVAC companies in his work. Genry and Bryan both believe that the future of the industry lies in a non-judgmental approach towards technicians and customers; Genry's consulting approach aligns with that vision for a better HVAC industry.

In South Florida, oversizing equipment is a severe issue. The hot and humid climate of South Florida leads to technicians oversizing the equipment to deal with the heat, but the runtime is too short to help with latent heat removal. So, Genry tries to get the full picture of an install by contacting everyone associated with the installation to gather information. He also focuses his education and training on correct equipment sizing and air balancing to help technicians in his climate zone.

Equipment sizing has to do with heat load and air balance. So, some of Genry's work also involves measuring pressures and balancing the supply and return air to maximize comfort. We also have to be aware of balancing heat and moisture when we adjust the structure or system.

Genry and Bryan also discuss:

Tech support
"Competing" for customers
Repetitive HVAC training and education
Data logging
Building occupancy and its effect on load
Helping consumers understand sizing issues
Load matching
Zonal pressure matching

Check out Genry's website HERE or contact him via his email address: garcia@cdi-hvac.com

Learn more about Refrigeration Technologies HERE.

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Short #48 - Drains Apr 02, 2019

In this short podcast episode, we talk about condensate drains. We get into the basics of cleaning, pitch, drain pans, and more.

Cleaning drains sounds like an easy task, but it can be a bit time-consuming and difficult to get right. Instead of just "blowing out the drain," you must check the entire drain and be aware of buildup in traps and other hard deposits that form inside the piping. Sometimes, you may need to use cleaners to dissolve the sludge and grime. Cleaning is about understanding the drain anatomy and checking it thoroughly to identify and attack the source of the buildup. You also need to clean the drain pan.

Drain pitch is also important for proper drain operation. The horizontal runouts need a slight downward pitch to move the pipe contents. We recommend using 1/4" per foot of fall on horizontal runouts. Insulation is also important on horizontal runouts in areas like attics and other unconditioned spaces.

Secondary drain pans should have about 3 inches of overlap in all directions, especially over the supply. Improper drain pan setup can cause messes later, and we don't want condensate dripping all over the place. Make sure you install your units in the proper configuration. Be willing to tweak the design to make sure the drain pan is sturdy and collects condensate well. As you would ensure that your unit is level, you need to make sure the secondary drain pan is level and supported properly.

You also need to think about float switches. If you have multiple float switches, you need to wire these in series. These components also require thorough testing; each one should be able to break the circuit.

We also discuss:

Strapping the drains
Venting
Double-trapping

Learn more about Refrigeration Technologies HERE.

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Can Manufacturers Specs Be a Crutch? Mar 28, 2019

Bert and Bryan discuss the commonly repeated phrase, "refer to manufacturer's specs," in HVAC work. They discuss when referring to the manufacturer's specs works and when it feels like a crutch.

Sometimes, you need to read the manufacturer's specs so that you can use the correct kits and components if specific parts or tools are necessary. Without knowing the specific product numbers given in the specs, you wouldn't be able to do the job properly. The manufacturer's literature can also explain equipment performance under certain conditions. In very specific applications, including VRF/VRV systems, you will want to be aware of specific procedures. Manufacturer specs also provide vital information for installations; while manufacturer literature can help with troubleshooting, the manual isn't always always as trustworthy for servicing equipment.

However, manufacturer specifications can also be outdated or incorrect. For example, many manufacturers refer to outdated evacuation methods in their literature; they use information based on poor vacuum pumps. Many manufacturers also recommend doing triple evacuation, but a deep evacuation can usually suffice without needing to do a triple evacuation. Manufacturers also aren't aware of products like Nylog that don't contaminate the system, so manufacturers advise NEVER to use thread sealants.

Overall, you must understand your equipment and use the manufacturer's specs to help you understand the equipment. If you use them as a step-by-step guide for servicing, then you may be using those manuals as a crutch. Some techs also use the specs to justify certain charges and services, which Bryan finds quite annoying.

Bert and Bryan also discuss:

Technician profitability
Advanced functions in the Ecobee thermostat manual
Flare leaks
Nitrogen usage
Understanding applications and misapplications
Customers, equipment failures, and spending money
Charging the customer "according to manufacturer specifications"

Learn more about Refrigeration Technologies HERE.

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Short #47 - Solar Mar 26, 2019

By viewer request, Bryan talks about some solar system basics in this short podcast episode.

Solar energy is an up-and-coming power source that will continue to emerge. However, oil is still very inexpensive, so the USA still depends on it quite cheaply. Many consumers also don't like the high up-front costs associated with solar energy. Photovoltaic energy creates a differential that moves electrons.

Many customers also object to the bulkiness and lack of aesthetic appeal of solar panels. However, in places with unstable electrical grids like Haiti, using the sun as an energy source makes a lot of sense.

American homes with panels can backfeed the grid, which makes the electrical company owe you credit for sending their energy back. The panels also store energy into batteries in areas with a weak electrical grid. However, these batteries can potentially be dangerous and expensive. Lead-acid batteries are commonplace in third-world countries. People use that stored energy at night when the sun can no longer power the panels. You need to calculate panel space, battery size, and peak solar times to create the most efficient system possible. Automatic shifting inverters can kick in and act as reverse charge controls that charge the batteries in both directions.

If you were to build an off-grid system, you can set up battery banks, use a charge controller, and connect the system to an inverter or even a generator to provide additional power; your goal is to look for energy gains. Some batteries are rated in amp-hours, so you need to know what that terminology is and how it affects voltage. Panels are often rated in wattage. Be careful about bucking phases; you do NOT want to do that because it is unsafe. You also don't want to use solar on refrigerators or freezers for hot pull down.

Learn more about Refrigeration Technologies HERE.

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Work-Life Balance, Real Talk w/ Bert Mar 21, 2019

Bryan and Bert talk through a real-life issue we all face as techs: work-life balance. Bert’s recent video “triggered” Bryan a bit, so they talk through it.

Bryan believes that the work-life balance doesn't necessarily exist; instead of creating balance, he believes in a focus on discipline in work and home life as you're present to each of them. Instead of setting rules for dedicating his time, Bryan focuses on setting goals that can improve multiple parts of his life. That is how he is able to work at a high level in his company, make videos and podcasts, write articles, and raise a large family.

The main issue that Bryan has with "work-life balance" is that the term focuses on value rather than focus. The term also implies that there has to be a 50/50 ratio of importance. He believed that Bert's video gave people license to give in to distractions at work.

Bert is more inclined to pick up his personal phone at work if his wife is calling. He knows how to make time for his family because he knows how much his family values quality time. However, he understands that creating expectations is not the way to promote focus and balance in life. He knows that it's easy to create an issue when people feel unloved if their significant other doesn't pick up the phone at work, so he and Bryan discuss what love, prioritization, and open communication really look like.

Bryan and Bert also discuss:

Expectations and disappointment
Balance and focus
When people change in relationships
How a spouse can promote focus in your work and home life
Boundaries
Enabling others
Managing distractions at work
Moving forward
When are you working too much?
Discussing goals and making hard decisions
Setting priorities

Learn more about Refrigeration Technologies HERE.

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Short #46 - Surge Protection Mar 19, 2019

Today's short podcast episode is all about surge protection on HVAC/R equipment. Lightning poses a severe threat to equipment, and surge suppression may or may not help.

Unfortunately, surge protection cannot protect HVAC equipment from direct lightning strikes. Surge suppression strategies connect to the high-voltage line and will protect your equipment from surges from the utility. Large, instantaneous spikes in voltage can mess up your equipment quite severely.

In general, we install MOVs (metal oxide varistors) as surge protectors in residential and light commercial equipment. Series mode (SM) acts as a low-pass filter that blocks higher frequencies, but MOVs are our main go-to for surge protection. When the voltage is within the clamping voltage, the metal oxide varistor shunts or redirects current to ground instead of the device; these devices have very high resistance, and they can fail when they get too hot. In thermal runaway, the MOV is very hot but continues shunting the current; as a result, the MOV is at risk of catching on fire. Thermal protection can exist for MOVs. MOVs also need a strong, secure ground connection to operate correctly. Make sure the MOV is connected, and a good way to do that is to test from leg to ground.

MOVs also require careful consideration during installation. These surge protectors can fit inside an ICM493 box that prevents catastrophic fire in the case of thermal runaway. Overvoltages below the clamping voltage can occur on MOVs, especially on inverter-driven compressors. ICM493s can also control overvoltages because they have voltage-monitoring capabilities (however, there is no published Joule rating). Both the LBK10 and ICM493 can shut off the equipment in the case of MOV failure.

Learn more about Refrigeration Technologies HERE.

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Intro to Boilers & Radiators w/ Moe Hirsch Mar 14, 2019

In this episode, we talk with Moe about the world of hydronics. We discuss some fundamentals and talk about various boiler and radiator types.

Hydronic systems use water flow to move heat. We can compare these systems to railroads; the water is like a train carrying BTUs, and the BTUs get off the "train" at radiators. The pump moves water in a circle, though it moves that water pretty far. Boilers generally require a certain flow, and if a single circulator pump can't achieve that flow, we sometimes need to bring on a secondary circulator.

Radiators can either be radiant or convective. Baseboards are a major part of conventional convective hydronic designs. Fin-tube baseboards are made of copper piping with aluminum fins on them. Cast-iron baseboards also exist and are commonplace in older homes, but Moe avoids installing them on newer homes. When designing systems, you don't want radiators holding on to heat for a long time. Recessed radiators go into the wall and are typically cast-iron; exterior walls require insulation. Freestanding radiators are typical of old designs but are making a comeback. Kickspace heaters go under cabinets and are fan-forced systems.

Old boilers are generally cast-iron sectional boilers, and some are steel. Cast-iron boilers tend to be either dry-base (fire on the bottom) or wet-base boilers (power burner/gas-gun type). These old boilers also usually have tube bundles, especially wet-base boilers. Modern high-efficiency boilers are common nowadays. Combi boilers (combination boilers) also fall into the modern boiler category. Combi boilers act as on-demand water heaters.

Moe and Bryan also discuss:

Relief valves and pressure margins
Purging hydronic systems
Hydraulic separation
Delta T and what it means for hydronics
Condensing boiler temperatures
Radiant vs. conventional baseboard systems
Hydronic towel warmers
Humidity and airflow control
Boiler runtimes
Short cycling and modulation

Learn more about Refrigeration Technologies HERE.

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Short #45 - OEM Parts Mar 12, 2019

In today's short podcast, we answer the following question: Should you ONLY use OEM parts? We also explain why the answer is what it is.

It can be tricky to determine the value of OEM parts in general. For example, many OEM capacitors are very prone to failure. Some non-OEM capacitors have much lower failure rates. Operating conditions may also exceed manufacturer specs, so aftermarket components may be better for equipment in extreme conditions.

When it comes to OEM parts, try to take those and the manufacturer bulletins at face value. However, you also want to do your own research. What are the OEM parts' fail rates? What are the operating conditions for the equipment? You have to ask yourself if the manufacturer's part is the most efficient and valuable one you can use for a given system. Go the extra mile to help your customers make the best possible decision for their unit based on efficiency, longevity, and price.

Some techs avoid using aftermarket parts because of liability issues. For the most part, liability isn't a huge deal except on flammable equipment like furnaces and R-290 systems. However, in many cases, the quality of parts like capacitors and relays may be far greater on aftermarket equipment. Motors can be tricky, especially on blower motors with distinct fan curves from the OEM equipment.

No matter what you do, make sure you consult with the customer and explain the benefits and drawbacks of each option so that the customer can make an informed decision. Also, follow your own company's guidelines.

Learn more about Refrigeration Technologies HERE.

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Special - Soft Skills Top Tips w/ Andy Holt Mar 08, 2019

In this rather unorthodox short podcast episode, Andy gives his timeless soft skills tips. We also tell you a bit more about a special training event in Orlando in just a few weeks.

Soft skills and communication are critical parts of the HVAC industry, especially residential HVAC. Customers don't compliment you on your tools; they compliment your service and attitude. We must acknowledge that we are in the people business and just happen to use tools when we work.

Andy recommends being on time for every job; if you think you might be late, call the customer to let them know. When you greet customers, make sure you smile and be friendly. Put your listening skills first; during that first conversation with the customer, pay attention to them and make sure you let them talk about all of their concerns. When working with a customer, try to make sure that everything you do comes from a place of gratitude.

Set the agenda with the customer and make sure that they understand exactly what the service entails. Show the customer everything you come across and involve them in the inspection and service process. Give the customer permission to follow you around and see what you're doing to build up that trust; the customer will know that you're doing your job and not trying to pull a fast one on them.

It also helps if you begin to view the customer as a component of the system so that you can keep their well-being at the top of your mind. We are troubleshooters above all, and we would probably all do a bit better if we saw the customer as another part that needs to be taken care of.

Find more at TopRate.com.

Learn more about Refrigeration Technologies HERE.

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Controlling Humidity For All Climates Mar 07, 2019

In today's podcast, Bryan covers some of the facts about humidity. He also explains how to keep humidity under control in all climates. Humidity refers to water vapor in the air and is a component of the air. Changes in temperature and pressure affect the density of the air. The air density determines how much moisture air can hold.

Relative humidity refers to the ratio of water vapor in the air. An RH value of 100% indicates that the air is saturated with water vapor; it has reached the dew point. At that point, the wet-bulb and dry-bulb temperatures will be the same. We do not want to reach the dew point inside a building.

Many people associate high relative humidity with high temperatures, but that association is a misconception. Unless the moisture content is extremely high at high temperatures, the RH will tend to be lower in hotter environments; hotter temperatures can hold more moisture. The moisture content at 90 degrees with 55% RH will be significantly higher than the moisture content at 65 degrees with 55% RH.

If the indoor temperature is below the outdoor dew point, we need to make sure we keep outdoor air out. We can do that by using ventilation strategies like bath fans and kitchen exhaust, especially since construction companies have built homes much more tightly over time. However, we want to ensure that we don't draw in low-quality air from the attic. We find that many humidity control strategies overlap with ventilation.

Bryan also discusses:

Wet-bulb depression
Insulating spaces and the effect on humidity
Dehumidifiers
Attic and crawl space dew points
Humidity drivers inside the home
Coil temperature, airflow, and dehumidification
Off cycle fan delay
Sweating and equipment freeze-ups
Running continuous fan

Learn more about Refrigeration Technologies HERE.

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Short #44 - Myth - Time as a Tech Equals Pay Mar 05, 2019

In this short podcast episode, we talk about the myth that time at a job or in the business equals or deserves pay increases.

Many people believe that showing up for a long time justifies a raise. They aren't necessarily progressing in their field, but they think they've spent enough time to warrant a raise. A business relationship is an agreement that you will perform specific tasks for a specified rate. If you don't go above and beyond or progress, then there's no reason for that pay rate to change.

Soft skills, cleanliness, and overall professionalism are also important to job efficiency and performance. If you don't improve those, then you may not give your employer a reason to believe that they should give you a pay raise. You are not owed more money because you have simply worked at a place for a long time.

If you work for a company that focuses on sales, the company has to make a profit for them to pay their employees more money. So, improving your own profitability as a tech will give you a case for deserving a raise. Investing in yourself can translate to success within the business. You will be a good earner only if you can bring quality work and skills to the table.

You can also choose to move to a different business or segment of the industry. Ultimately, you have to invest in yourself and make decisions for yourself. Your value does not depend on how much time you spend with a company or in the industry. As a technician, your value depends on the work you put into the industry.

Learn more about Refrigeration Technologies HERE.

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Chiller and Cooling Tower Cleaning w/ Goodway Feb 28, 2019

In today's podcast episode, Mark Roth from Goodway talks about chiller and cooling tower cleaning best practices and techniques. Goodway makes industrial maintenance equipment for the HVAC industry, especially tube-cleaning equipment.

A chiller has water running through the tubes, and debris from the cooling tower can build up in the tubes. When scale or debris buildup occurs, heat exchange becomes much less efficient. Water hardness can also interfere with heat transfer; harder water will lead to more mineral deposits. So, tube cleanliness is important, especially in high-traffic areas. In those areas, cleaning should happen at least once or twice per year.

To access the tubes, you have to take the heads off the chiller. Cleaning the tubes is usually easier than taking the heads off the chiller. When cleaning the chiller and cooling tower, the water flows onto the floor and to a drain. So, floor cleanliness is important when wrapping up a job. "Chiller bibs" also exist to catch the water and transport it to the drain with less of a mess.

Cleaning machines often have foot-pedals, and people commonly put toolboxes or other heavy objects on foot-pedals, which is a bad practice. People also need to tighten the brushes to their cleaning machines with channel locks; when techs don't tighten those brushes properly, the brushes can fall off, which is not good for the chiller.

Cooling towers act as filters, so they collect a lot of debris in the basin. Goodway has a vacuum that collects the debris in the basin without having to drain the entire thing.

Mark and Bryan also discuss:

Basic chiller and cooling tower anatomy
Legionella
Using machines for cleaning
Enhanced tubes
Nylon, brass, and stainless steel brushes
Makeup water and filtration strategies
Cooling tower media
Descaling strategies and products
pH balance

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #43 - Is IAQ a Joke? Feb 26, 2019

In this short podcast episode, we address the myth that IAQ is a joke. We also discuss how to think about IAQ correctly in HVAC work.

Indoor air quality is NOT a joke. However, it has a bit of a bad reputation in our field due to the overuse of accessories and bells-and-whistles to solve whole-home air quality issues. (Oxidizers, UV lights, etc. can help IAQ issues, but they are not a fix-all.)

We don't want completely sterile air, just as we like to have a beneficial microbiome inside our own digestive systems. However, there are also a bunch of things suspended in our air that are really bad for us. Some of those bad things include VOCs, carbon monoxide, and radon. Many of the products we bring into our home, including furniture assembled in underregulated factories overseas, end up off-gassing harmful substances into our air. VOCs have a distinct chemical smell, and proper ventilation helps solve the problem.

Media filters are an everyday object that we use to help control IAQ. Using higher-MERV filters help keep the air free of particulates, but you must size them correctly to prevent excessive pressure drop and poor airflow.

To control moisture problems, we want to make sure we seal buildings as tightly as possible. We also want to make sure we use designed pathways and effective ventilation strategies. Kitchen and bath exhaust fans should be functional. When we think about bringing in outdoor air, we want that process to be controlled, and we want to make sure we're bringing in high-quality outdoor air.

Carbon monoxide and carbon dioxide are both undesirable in terms of IAQ, but carbon monoxide is potentially deadly. We want to make sure we vent those gases, especially CO.

Learn more about Refrigeration Technologies HERE.

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Propane Refrigerant - A Tech Perspective w/ Chris Stephens Feb 21, 2019

Chris Stephens from HVACR Videos joins us to talk about his experiences with and perspective on R290 (propane) refrigerant in restaurant refrigeration.

Chris sees R290 propane on a daily basis, and his perspective as a tech differs from that of an R290 equipment manufacturer. While the temperature sensitivity contributes to flammability, R290 is also under pressure in a system. Therefore, propane refrigerant systems require a lot of caution.

R290 equipment must undergo thorough redesigning to be entirely spark-proof. Hydrocarbon refrigerants also require OEM components; aftermarket components change the design and can cause problems down the line, and technicians WILL be liable for any damages related to aftermarket components. When techs evacuate/recover R290, all evacuation and recovery tools must also be spark-proof; you also need to check to make sure that those tools are certified to work with propane refrigerant, even digital gauges. When using approved service gauges, also be sure to use short hoses. More so than ever, following the manufacturer's guidelines is an invaluable practice.

Unlike R-22 and R-410A, you CAN vent R290. However, the location should be well-ventilated. Chris recommends that you take extreme caution when venting refrigerant, such as by using a leak detector to let you know when to stop. Most of all, we need to be aware of our surroundings when we work with highly flammable R290. When we use our senses and are aware of our surroundings, the refrigerant becomes much more predictable.

Chris and Bryan also discuss:

Buying and sourcing R290
Recommended R290 training resources
Piercing valves
Basic R290 behavior
Flowing nitrogen
Evaluating hydrocarbon systems and using a "common-sense" approach
Leak detectors to avoid using for R290 systems

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #42 - Myth - Flame Rods Feb 19, 2019

In this short podcast episode, we discuss the common myth about cleaning flame rods/sensors/rectification devices.

Flame sensors or rectification rods are NOT the same as thermocouples or thermopiles. Thermocouples and thermopiles use two dissimilar metals to create a temperature differential. So, we do not clean thermocouples and thermopiles because the heavy abrasives in cleaners can damage and reduce the effectiveness of those devices. However, you don't have to worry about that sort of damage on a flame sensing rod; we can indeed clean those.

The flame rod sits in the flame (regardless of ignition type) and allows for a DC current to travel through the ions in the flame to ground. The flame creates a path for that current, which makes a closed circuit. Flame sensing rods are merely pieces of metal that allow current to flow when there is an active flame on a furnace.

So, you want to keep your flame rods clean to allow for conduction. You may want to avoid using sandpaper or Emory-type materials to clean the rods because sediment can build up on the flame rod. When the flame ignites, the sandy substance on the rod can turn glassy and impede conduction. However, you can use an appropriate cleaner without damaging the rod. You can also replace the rod if you happen to have one on your truck, but you don't have to replace all dirty rods.

Pool heater flame sensors can get exceptionally nasty due to the chemicals they encounter. If a piece of equipment has a flame rod that gets dirty a little too quickly, try to find the cause of the excess grime and take care of it.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Installing Central Air From Scratch w/ Eric M Feb 14, 2019

In this podcast episode, Eric and I discuss his new home and his plans for installing central air the Eric-Mele way. Eric's home doesn't have an attic, crawlspace, or basement. So, designing and installing central A/C will be a challenge, especially since Eric doesn't like high-wall ductless systems.

Eric considered using an air handler with exposed ductwork, but he doesn't want the noise issues associated with that design. He also considered using a package system, but it has the same noise concerns as the previous option. In the end, he decided to go with ceiling cassettes. Cassettes have a condensate pump, differentiating them from high-wall ductless systems and making them a bit more expensive.

Eric has also collected his latent-sensible capacity data. Moisture removal is critical in his South Florida home, and equipment sizing is an important factor when installing central air. Sizing contributes to dehumidification because of its effect on runtime. However, smaller ductless/VRF units may not have sufficient heat even when they're properly sized. In the future, we expect companies to utilize heat sensors to improve the sensible heat ratio when moisture removal is needed.

For filtration, Eric plans on seeing how the fan motors react to pleated filters. Upgrading the filters could help control sensible heat ratio and VOC contamination, but static pressure remains a concern.

We also discuss:

Ductless unit cleaning
Filtration for air handlers with exposed ductwork
Lagging vs. drilling
Ceiling cassettes and condensate pumps
Flex vs. duct board vs. metal ducts
Oversizing VRF
Two-pipe systems
Activated carbon filtration
Making flare fittings vs. brazing in factory-made flares

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #41 - Context in Education Feb 12, 2019

In today's short live podcast, Bryan discusses the importance of context in education and the challenge presented by information.

When we learn, we do ourselves a disservice by searching for information alone. Just-in-time education allows us to "search instead of research," and it works in a limited and inefficient way. Instead, we'd be much more effective if we knew how to learn efficiently. To learn efficiently, we need to bring context to the learning process.

Instead of focusing on raw facts or abstract information, we need to know about the surrounding information. It's also beneficial to use similes and metaphors to grasp how something works. In other words, we need to connect new information to past experiences. Therefore, the learning process that most of us accept seems rather backward. Instead of feeding people answers immediately, we can supply them with experiences that can help them draw similarities between those experiences and demonstrations and the theoretical elements.

The goal of context in education is to equip us to understand situations and solve problems repeatedly. As humans, we are likely to forget information that is fed to us directly and not connected to our experiences.

Ideally, a learning process would begin with observation. We would show students how to do something or how something works. Then, we explain the theory behind why that thing works. Finally, the student or apprentice would be given the space to apply the principles themselves and work with their own hands.

We also answer questions and respond to comments about:

The value of schooling
MeasureQuick compatibility
Self-driven curiosity
Companies working with educators

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

VRF/VRV Design w/ Jordan Cummings Feb 07, 2019

In this episode, Jordan Cummings comes on the podcast to review application-based system selection considerations for VRF/VRV systems.

A VRF/VRV system works a bit like a hydronics system, but it provides hot or cold air to various zones in a space, not water. The key to having a reliable and long-lasting VRF system is a good installation. Proper maintenance practices, including pulling deep vacuums for dehydration, will also improve the performance and life of a VRF system.

When you choose a system to install, you have to determine if you want a heat pump or heat recovery system. Occupant type will play a major role in that equipment selection. Budget is also a variable, but it is typically less of a concern than occupant type and building purpose.

Some VRF/VRV systems that have been primarily designed for cooling may need to provide heating in low-ambient conditions. In many cases, these will close fresh-air dampers and recirculate discharge gas. Some units may even have auxiliary heat or be backed up by other heating equipment. Defrost is also something you'll need to consider in low-ambient applications.

Sizing is another important part of VRF/VRV selection and design. Consider nominal capacity but don't accept it as a hard and fast value. Keep your design conditions in mind; which temperatures and humidity percentages are you trying to maintain? What is the outdoor air temperature? Also, think about the piping total equivalent length and the estimated total distance between the outdoor unit and the farthest indoor unit.

Jordan and Bryan also discuss:

Buildings with cooling towers and boilers
SEER vs. IER
Aurora VRV equipment and technology
Connection ratio
Air handler unit and branch box selection
Control boxes and accessory selection
Discharge air control
Condensate control
Maintenance concerns for VRF/VRV systems
Indoor unit turn-down

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #40 - Specifically Relative Feb 05, 2019

In today's short podcast episode, we talk about specific gravity, also known as relative density. We explain why it matters to technicians.

When we talk about specific gravity, we're actually talking about density. We're actually using that value to assess how a vapor or liquid's density compares to air or water, respectively. Regardless, we are working with the pressure conditions of 14.7 PSIA, or atmospheric pressure.

In the case of liquids, we're relating them to water is at its densest, which is 39.2 degrees Fahrenheit. You may have noticed that ice cubes float in water. That's because water becomes less dense as it gets colder than 39.2 degrees and when it freezes. Ice is less dense and more buoyant than water.

So, specific gravity requires a reference. Because it requires a reference, it is also a relative measurement, so "relative density" is another appropriate term for specific gravity. Regardless of units, we are still comparing one thing to a constant in the form of a ratio. (For example, a liquid with a specific gravity of 0.85 is equal to 85% of the density of water at 39.2 degrees Fahrenheit.) The relative density also explains why some liquids sink and others float when mixed together.

Gases can also rise or sink based on how much lighter or heavier that gas is when compared to air. If the specific gravity of a vapor is less than one, it will rise to the ceiling. Natural gas is an example of that. If the specific gravity of a gas is greater than one, it will sink. LP is heavier than air and will sink. Therefore, LP is a bit more dangerous than natural gas because of how it takes up space due to its interaction with the air.

Learn more about Refrigeration Technologies HERE.

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R290 (Propane), What you need to know w/ Embraco Jan 31, 2019

In this episode, we speak with Embraco about R290 (Propane) refrigerant, hydrocarbons, and what you need to know about them. Embraco is primarily focused on compressors and is involved in the residential and light commercial market.

The greater demand for natural refrigerants or hydrocarbons has made R290 popular. Hydrocarbons have hydrogen and carbon chains; although these refrigerants are very similar to grill propane, they are much drier and purer. R170 is another hydrocarbon for very low-temperature refrigeration. In some European countries, R290 and CO2 are becoming much more prevalent than synthetic solutions. China has invested a lot in hydrocarbon technology, and the United States has shown interest in using hydrocarbons for auto coolers and natural refrigerants for grocery refrigeration.

R290 is flammable, but most techs' aversion to working on those systems likely stems from a fear of the unknown. These systems have several safety controls that prevent gas leakage from getting in contact with sparks. So, these systems rarely ever catch fire. Embraco also has a commitment to putting safety first when they design compressors.

You can also vent R290 to the environment, which you can't do with many other refrigerants. Unlike other refrigerants, R290 has a very low global warming potential. R290 and CO2 are not perfect, but they will be the future as we move away from ozone-depleting substances and greenhouse gases.

R290 is also making its way into the residential sector. You can find it in smaller applications, such as mini-fridges and even some other domestic refrigerators.

We also discuss:

Overloads and why systems aren't as flammable as they seem
Terminal venting
Embraco's design goals and philosophy
Contamination and evacuation

Links:

http://refrigerationclub.com/

http://naturalrefrigerants.info/

http://embraco.com/Default.aspx?tabid=40

Learn more about Refrigeration Technologies HERE.

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Short #39 - Tricky Amperages Jan 29, 2019

We talk about measuring tricky amperage on a blower and condensing fan motor. We also cover why you may be measuring inaccurately, resulting in a misdiagnosis.

When measuring amperage on a PSC blower motor, you may have noticed that amperage on the common is higher when the panel is off. Conversely, on ECM or X13 motors, the amperage is generally lower with the panel off. When measuring amperage, we recommend using a Bluetooth ammeter to take readings without letting the panels interfere with your measurements.

Anytime the amperage is low, the more difficulty the ammeter will have in measuring an accurate value. In cases where you're dealing with a very low amperage, you will need a higher-resolution ammeter for accurate measurements. One old-school way that you can increase your resolution is by using the 10-wrap method and putting that in series. Then, you take the amperage measurement and divide it by 10.

We don't recommend doing the under-load test on a blower; a bench test is much safer. However, the compressor and condenser fan motor capacitance can be measured under load. Outdoor tests can be a bit challenging because there is a greater possibility for interference. Current drawn outside of the clamps can indeed affect the reading, and several other nearby conductors draw current inside condensing units.

Sometimes, technicians replace perfectly fine run capacitors because the amperage seemed too high on an under-load test. To avoid interference, perform a bench test and check the actual microfarads. Tricky amperage interference also leads techs to condemn condenser fan motors when they really just picked up amperage outside the clamp. So, keep in mind that your meter could be running high or picking up interference. Any possible fail parts should undergo further testing to confirm that there's something wrong.

Learn more about Refrigeration Technologies HERE.

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Beacon 2 Refrigeration Talk Through Jan 24, 2019

In this service manual talk-through episode, Eric Mele helps us discuss the Heatcraft Beacon 2 refrigeration system. We talk about what it can do and what it entails.

The Heatcraft Beacon 2 is a refrigeration system with more electronic controls than electromechanical. However, it is quite user-friendly, and it allows you to see what the system is doing at almost all times. The monitor doesn't allow you to adjust anything in the system, but it lets you see valve position, superheat, time until defrost, and more as the system is operating.

The Beacon 2 has a suction pressure transducer that maintains superheat. You can dial in the superheat on the control, and the system should control it almost exactly as long as all the components are working properly. You can also manipulate the wiring to run multiple evaporators off of one condenser. (There are master and slave evaporators, and you must differentiate them when configuring the controls.)

When it comes to parameters, you have to set your defrost type to air or electric. In general, you use electric defrost for freezers. You must also set your refrigerant type accordingly. Then, you set your box temperature. Medium-temperature applications tend to be around 35 degrees, and many low-temperature applications tend to be around -10 degrees. You also have control over defrost settings and temperature units (Fahrenheit or Celsius). You can also find frequent parameters on the evaporator panel for more information.

Most errors will be sensor errors. Many sensor issues are easy to test because of the user-friendly monitors. You can compare your reference sensor to the data to check the accuracy of what's being reported to the board.

Eric and Bryan also discuss:

Forcing pump-down and defrost
Schematics and wiring practices/applications
Headmaster valves
Setting pressure controls
Defrost frequency and failsafe

Learn more about Refrigeration Technologies HERE.

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Short #38 - Low Ambient Cooling Jan 22, 2019

This short podcast episode covers the why and the how of low ambient cooling and refrigeration.

Low ambient cooling refers to operating A/C equipment during low outdoor ambient conditions. Typically, the cap of operation is around 55 or 60 degrees. However, some commercial facilities need cooling when the outdoor temperature is cold. For example, those facilities may have to cool electronics or large volumes of people. In buildings that don't have economizers, running the A/C in cold ambient conditions may be the only option. The same applies to restaurants, which always need to run freezers and coolers.

When the outdoor ambient temperature drops, the condenser rejects more heat to the outdoors. Head pressure drops, and there may be an insufficient pressure drop across the metering device. We also can't run A/C evaporator coils below 32 degrees, as there is no defrost mechanism in straight-cool A/C systems. So, the strategy to get around those issues is to focus on raising the head pressure by modulating the condenser fan motor.

A fan cycling control can turn the condenser fan on and off based on pressure. So, we try to maintain a fixed pressure in the condenser by allowing that control to shut off the fan when the pressure drops too much. However, fan cycling can be a bit jarring for the system.

Motor master controls help modulate the motor by decreasing voltage to the motor. However, that fluctuating voltage isn't necessarily good for the motor. In those cases, you must have a ball-bearing motor. Unlike the motor master, a refrigeration headmaster is a valve that allows discharge gas to enter the drop leg.

Variable frequency drives can work with a three-phase motor to vary the speed of the motor. When the speed can vary easily, you can manipulate the pressure.

Learn more about Refrigeration Technologies HERE.

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VRF in Real Life w/ John Oaks Jan 17, 2019

In today's podcast, I talk to John Oaks about his experience as a VRF tech in the field, including branch boxes and two-pipe vs. three-pipe technology. John primarily works on the troubleshooting and service side rather than the installation and programming side of the field.

Variable refrigerant flow (VRF) systems, also called VRV systems when manufactured by Daikin, are commercial HVAC systems. VRF systems work best in commercial buildings with some degree of fragmentation, like offices and medical facilities. These systems are similar to multi-zone ductless systems, but they operate on a much larger scale. VRF systems have a branch box, which acts to direct traffic between the various zones of a building and parts of the system; the branch box allows the unit to heat and cool simultaneously.

A 24v signal drives most of the controls. These controls are "daisy-chained," as VRF systems are very interconnected, and a defrost signal can have up to about 50 destinations to various components. The entire VRF installation process requires careful attention to detail, not just on the programming side.

When it comes to common issues with VRF systems, the refrigerant charge is one of the most critical problem areas. These systems mask issues with the charge, so it is difficult to find out if a system is undercharged or overcharged. In addition, you can't weigh out the charge in the same way that you would in a residential system.

John and Bryan also discuss:

Metering device placement
Industry improvements and upgrades
Inverter boards
Line set length and charge issues
Flares, brazing, and ZoomLock
Condensate removal and drainage strategies
Diversity of zones and efficiency
Two-pipe vs. three-pipe configurations
Cooling mode, heating mode, and mixed conditions

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #37 - The Trade Skills Gap: A Manifesto Jan 15, 2019

This is a voice-over audio presentation of the article of the same title on the HVACRschool.com website ("The Trade Skills Gap: A Manifesto).

The manifesto discusses the value of technicians and the trades in modern society. It also covers the plague of snobbery that we are all too familiar with in the world.

You can read "The Trade Skills Gap: A Manifesto" HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Furnace Sequence Of Operation Jan 10, 2019

Jason Obrzut comes on the podcast and talks us through his furnace sequence of operation training: "Take It Slow, It's Gonna Blow!"

There are 6 main steps in Jason's furnace sequence of operation training. The phrase, "Take It Slow, It's Gonna Blow!" should help you remember the sequence (Thermostat, Inducer motor, Safety switch, Igniter, Gas valve, Blower motor).

The first component in the furnace sequence of operation is the thermostat, which initiates the call for heat. So, the thermostat has to send the signal to the circuit board. After the board receives that signal, it sends 120v out of the board to the inducer motor.

Next, the inducer pulls the gas combustion air into the heat exchanger. That air will then be deposited into the exhaust. The inducer is what aids the venting action and is a critical part of a furnace.

The safety switch is a general term for a negative pressure switch with a hose connected to the inducer housing or heat exchangers. Negative pressure from the inducer motor will close that switch. When that switch closes, 24v goes back into the board.

Then, the board sends a signal to the igniter. Now, you will finally begin to see heat delays. Silicon carbide and silicon nitride are common igniter materials nowadays, but they are fragile.

Once the igniter has worked long enough, the gas valve opens. We get 24v from the board to the gas valve, which brings on the gas flow and starts a timer.

When the timer expires, the blower motor will come on. This component is the LAST one to come on.

Jason and Bryan also discuss:

Pressures on the flue
Cracked heat exchangers
Safeties not closing
Hot-surface vs. intermittent-spark vs. direct-spark ignition
Flame sensors and proving flame
DIP switches

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #36 - Stack Effect Jan 08, 2019

In this short podcast episode, we talk through stack effect. We explain what it is and what sorts of comfort issues it can cause in a home.

Most of us understand that hot air rises even though heat itself doesn't rise. The stack effect is precisely a version of that piece of common knowledge; hotter air is less dense than cooler air, so it floats above the cooler air. In hotter air, the molecules move a lot faster than they do in cooler air, so they can start to separate from each other, which reduces the overall air density.

For the most part, we don't work pressurize air in HVAC work (not refrigerant), but we do change the temperature. The temperature changes cause the difference in air densities to emerge.

If we're dealing with a furnace system in a two-story house or a home with high ceilings, we see that stack effect in action. When that hotter air rises and cooler air sinks, the hotter air makes way for a vacuum that draws colder air into the building. While that hot air rises, the colder air comes in under doors and through low cracks. Although the air that's coming out of the appliance is warm, it can't do much to heat the space before rising.

The reverse stack effect can also happen. When you have poorly sealed can lights or cracks in the ceiling, the colder, denser air will sink and create negative pressure near the highest point of the room. When we have that negative pressure, hot air can get pulled in from the attic or other undesirable locations. In Florida, we have to worry quite a bit about the reverse stack effect, whereas the stack effect is more of a concern for colder climates.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Future of App Based Diagnosis w/ Jim Bergmann Jan 03, 2019

Jim Bergmann gives us a year-end review of all that is happening at MeasureQuick and his predictions for the future of app-based diagnosis. He also covers what's been going on with Redfish, BluFlame, BluVac, Supco, Testo, and Fieldpiece.

Diagnostic tools only work if the buyers understand how to use them. When apps can assist the tool buyers and users with diagnosis, the tool manufacturers can focus more on improving the technology; they can leave the software and education to mobile applications. Implementing gas appliance diagnostic education has been a challenge for Jim and other app developers. However, they are attempting to take app-based gas appliance diagnosis to the next level. The goal of diagnostic apps is to educate technicians about tools and readings and to make diagnoses more comprehensive.

From the start, one of MeasureQuick's major focuses has been accessibility and ease of use. A diagnostic app that gives technicians a seamless way to take readings, store data, and learn about their measurements should be easy to use, so Jim has put a lot of work into making a user-friendly app. So, the next step for MeasureQuick in terms of accessibility will likely be to allow users to share data for remote viewing.

MeasureQuick has incorporated education on the basic refrigerant circuit, electrical components, gas appliances, and vacuum within the app. Soon, Jim would like MeasureQuick to expand into the refrigeration and geothermal sides of the HVAC/R world; he'd also like to implement project notes.

Jim and Bryan also discuss:

Monetizing diagnostic apps
Tying tools into diagnostic software
Wireless range and BlueTooth considerations
Working with programmers
How much might I invest in an app-based diagnosis app?
Third-party quality control
Future-proofing
Project or process-based functions
Integration
Electronic accessibility and pricing

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #35 - Resolution, Precision & Accuracy Jan 01, 2019

What is the difference between accuracy, precision, and resolution? In today's short podcast, Jim Bergmann explains the differences and why they matter.

People commonly confuse accuracy and precision. Accuracy refers to how close a measurement is to the correct value, but precision refers to the consistency of values. For example, you can get several infrared thermometers to measure the difference between circuit breakers, and the thermometer readings all come out close to the same value. They aren't necessarily accurate, but they are precise.

In cases where we use a voltmeter to measure for the presence of voltage, we don't need a high degree of accuracy. However, when we want to measure exact voltage values, we want to make sure our tools are accurate. Sometimes, voltage that is too low can cause issues with the circuit boards.

Resolution refers to the smallest possible amount of change you can detect. For example, one voltmeter may measure to the nearest whole volt, and another may measure to the nearest tenth of a volt. The resolution is higher on the latter voltmeter, as it detects a smaller change than the first voltmeter. Some tools measure with a high resolution, but the increased resolution may compromise the accuracy. For example, if a manometer reads into the Pascals range, it may only have a tolerance of +/- 5 Pascals, which leaves room for inaccuracy.

However, again, accuracy is not always the most important value. Sometimes, resolution and precision are more important than accuracy. After all, in the words of Jim Bergmann, it's pretty difficult to measure feet with your car odometer. One common example where precision and resolution are more important than accuracy is when techs try to measure microns with analog gauges. The accuracy means nothing when the precision and resolution are poor.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Ventilation w/ John Semmelhack Dec 27, 2018

John guides us through all aspects of ventilation and system design. He gives us a review of point ventilation, ASHRAE 62.2, whole-home strategies, and much more.

Nowadays, construction protocols instruct builders to make houses tighter than the builders of the past. The goal of building tighter homes is to give us more control over the temperature, quality, and energy impact of the outside air we bring into our homes.

Common sources of ventilation are local exhaust systems, including bath fans and kitchens. However, in tighter constructions, there is a greater need for whole-home strategies to bring in outside air and dilute indoor-generated pollutants. Some of those pollutants include VOCs, odors, and moisture. We must think about how to introduce that outside air into the home and how that outdoor air will impact heat loads, moisture levels, and air quality inside the home.

When we select equipment for airflow, we need to think about constant vs. intermittent flow. In humid climates, you also need to take extra steps to prevent moist outdoor air from leading to excess condensation in the home. Ventilation equipment either delivers outdoor air to each room or mixes that outdoor air with the return air. Try to ensure that the space temperature doesn't drop below the dew point, which can be a challenge in humid climates.

Ventilating dehumidification is a promising solution for HVAC system replacements and new constructions in humid climates. In cold, tight homes, ventilating dehumidification can keep a home dry enough to keep occupants comfortable in the winter.

John and Bryan also discuss:

Why do people want energy efficiency?
"Passive house" and airtightness standards
Mixing air and filtration
Carbon dioxide (CO2)
ERVs vs. HRVs for balanced ventilation
Fan cycler systems
Duct installation quality
Dedicated make-up air
Fireplaces and gas appliances under negative pressure

Learn more about Think Little, John's company, at think-little.com/.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Gas & Combustion Tools w/ Bill Spohn Dec 20, 2018

Bill and Bryan discuss gas and combustion tools. These tools include manometers, combustible gas detectors, personal CO detectors, draft gauges, and combustion analyzers.

Manometers measure gas pressure, and they require calibration but are usually quite accurate. Before using a manometer as a diagnostic tool effectively, you must understand your targets and resolution. Some digital manometers come with BlueTooth technology, so you can log, convert, and store your data on mobile devices.

Gas leak detectors are relatively inexpensive tools. These should NOT be confused with combustion analyzers, which are different tools altogether. You usually cannot calibrate these tools. When using a gas leak detector, the leak detection process on gas pipes is similar to the electronic leak detection process on straight-cool A/C units.

Draft gauges measure very fine pressure differentials in the combustion air zone. These may use flappers or vanes to give you data about the direction and amount of draft. Most importantly, you want to ensure that you have no backdraft. These tools take very fine measurements, so they have high resolution. Because of their high resolution, they require frequent calibration to stay accurate.

Personal (or ambient) CO monitors are also important gas and combustion tools. Carbon monoxide (CO) is odorless and colorless, and it can be deadly. To avoid CO poisoning, use one of these monitors to remain aware of the CO content in your space.

Combustion analysis has evolved a lot over the years. Today, we perform combustion analysis with a single tool. When combustion occurs, a chemical reaction occurs. Combustion analyzers determine what happens post-combustion by taking temperature and oxygen readings. However, they also account for the presence of CO, which indicates incomplete combustion.

Bill and Bryan also discuss:

Analog and Magnehelic manometers
BPI-1200
Precision
CO monitor upkeep/disposal
Perfect combustion
AHRI-1260
Nitric oxide filters
Choosing tools

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #34 - Heat Pumps Dec 18, 2018

In this short podcast episode, Bryan speed-talks through all the basics of heat pumps and how they function.

Heat pumps are not physical pumps or components on an A/C system. A heat pump is an HVAC unit that is also capable of heating a home by reversing the refrigeration cycle. When that reversal happens, the traditional indoor "evaporator" coil acts as a condenser that rejects heat in the home. As such, the traditional outdoor "condenser" acts as an evaporator that absorbs heat from the outdoors so long as the refrigerant is colder than the outside. Due to how they function, heat pumps are more common in warmer climates.

The heat pump's reversal happens on the reversing valve, which diverts refrigerant right before the compressor. A solenoid shifts the valve when you enter heat mode from cool mode (or vice versa), and that's how refrigerant gets diverted. These just slide back and forth, and they are pretty reliable; they don't typically malfunction. Before a reversing valve can work, the system must be ON; the valve cannot shift if the unit is OFF.

Heat pumps typically have two metering devices, one by the indoor unit (cool mode) and one by the outdoor unit (heat mode). A check valve controls the flow of refrigerant to the correct metering device. Heat pump systems may also often have suction accumulators and crankcase heaters to help prevent oil loss and flooded starts in the compressor. The defrost controls for heat pumps typically have a timer and defrost sensors.

We also discuss:

Issues with heat mode TXVs
Checking the charge on a heat pump
Defrost sensor types and operation
Auxiliary heat
Economic balance point

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

EPA Regulation Uncertainty w/ Jason Obrzut Dec 13, 2018

Jason from ESCO and Cengage comes on to talk about the varying landscape of EPA 608 regulations with what you need to know for now (circa 2018).

The EPA has proposed to roll back some regulations regarding HFC refrigerants, including leak rate and leak repair mandates. There are also questions about the regulation of refrigerants that do NOT have ozone-depleting substances, not just HFCs. This choice reinterprets language within the guidelines put forth in 2016 and the Clean Air Act. However, this choice completely disregards global warming potential and limits regulations of refrigerants with global warming potential but no ozone-depleting potential. EPA 608 still prevents the venting of non-natural refrigerants, but the proposed changes aim to clarify the language in those regulations.

EPA 608 Subpart F can potentially be rescinded entirely. That action could muddy the language as to what constitutes venting. HVAC businesses can also suffer, as technician certification may no longer be a requirement for purchasing refrigerants. (Not to mention, homeowners can ignorantly engage in harmful practices, like cross-contaminating refrigerants and venting. Substance abuse is also much more accessible if non-HVAC techs purchase refrigerant to huff it.)

The USA is actually well behind other industrialized countries when it comes to refrigerant usage. We're one of the only industrialized countries that have yet to really move forward from HFCs. So, rolling back HFC regulations may be a step back for environmental initiatives, refrigerant innovation, and even the refrigerant reclamation job market in the USA.

Jason and Bryan also discuss:

EPA exam changes
Individual state regulations and certifications
Who benefits from these changes?
Comparisons to other toxic chemicals
Air quality, pollution, and resource exploitation
Refrigerant recovery and mixing
How will this change affect the job market?
How will this change affect education and writing?

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #33 AMA - Business Tips Dec 11, 2018

In this short podcast episode, Bryan shares his experience as an entrepreneur and his tips for anyone who wants to run and grow a successful business.

When growing a business, the best thing you can do is listen to others who have started a business. It's especially useful to listen to those who have already "made it" in the business world.

Growing a business requires you to stay focused. While you may have to work in your business, you also want to make time to work on the strategic parts of your business. Make goals, hire good people, and make sure your business has all the right people and tools to help it grow. Know your hirees' motives, and it's also important that the people in your personal life support you. Your business will also grow most effectively if you can keep your emotions under control.

On a financial level, you need to have a good grasp of your personal finances before tackling business finances. Make wise decisions, and don't make excuses to spend money on things your business doesn't actually need. One of our main business tips is that it's best to avoid dumping your money into things you don't understand. Marketing is something that a lot of HVAC businesspeople don't understand and may not actually need. So, keep your investments limited to things you understand early on.

Networking is a critical element of business. Your business needs to develop relationships with people you can trust. Trust-based relationships help foster an appreciation between your customers and your business. Appreciation for employees is another element of this. When everyone is aware of the value of your relationships, your business can grow with the right people within the company and the right people paying for your services.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

AMA#1 - State of the HVAC School Union Dec 06, 2018

In our first ever ask-me-anything (AMA) podcast, we talk about the trade as a whole and answer random questions about Kalos and myself.

Some people ask me if I'd encourage my children to get into HVAC/R. In my opinion, the trade offers plenty of good opportunities and room for growth. So, I will definitely encourage my children to get into the trades, but I will not pressure them into it. I think more of us should encourage our children to consider a career in the trades and understand the benefits of those careers. I'd even say that I'd choose this career path again if I were allowed to restart my life and take a new career path.

I'm optimistic about the future of the trade. The pay and opportunities are better than they've ever been before, and we have chances to attract young people to the trade. This trade is one of impact, and impact is becoming increasingly important to young people.

One of the main issues we need to address in our trade is unprofessionalism. From bad practices to blatant prejudice, we need to be professional, proud of the work we do, and fair to everyone.

We also discuss:

Which piece of equipment I identify with
Sleep schedules for people who work on many things at once
Providing tools and tool stipends
HVAC company finances and profit
Tech traits across trades
The separation between commercial and residential HVAC
Unprofessionalism in the trade
Taking time to read and do research
Time management and discipline
Mechanical diagnosticians vs. sales techs
What inspired me to get into HVAC
Innovation, marketing, and corporate culture among manufacturers
Onboarding and training green techs

Thanks to everyone who asked questions in this AMA.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #32 - "It's Undersized" Dec 04, 2018

When we replace equipment, we sometimes wonder if the old unit was undersized. Here are some things to consider before replacing that old A/C with a bigger one.

When we do load calculations, we figure out how much heat to remove or add to a home based on the building's design. We need to account for how much heat is entering or leaving a building and heat gains on the inside of a space. Heat gains can come from human body heat or electronics running, and heat losses are quite rare. Those factors are perhaps even more important for correct sizing than mere square footage.

In general, I don't recommend putting a bigger unit in. Focus on getting the equipment to work properly before considering an upsize, as the improper cooling could be caused by a mechanical issue and not an undersized unit. If you want to dig deeper and consider upsizing a unit, you have to consider a few things.

First of all, you want to look at the sensible and latent loads. Is the unit too small on the sensible or latent side? In either case, you can adjust the blower to try to address these first. If humidity is the issue, you do NOT want to oversize the unit.

Is leakage a factor? Check the integrity of the duct system and if you have cracks, can lights, or other sources of leakage. How's our ventilation? Attic ventilation is also a huge factor that will determine how well an A/C unit works.

We also discuss:

Shade and impact on radiant gains
Ductwork, wire, and copper pipe sizing
Heat load reduction (lighting, ventilation, etc.)

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #31 - U-Factor and R-Value Nov 27, 2018

What is the difference between r-value and u-factor? Why should we care about the differences? In this short podcast, we'll explain what those differences between the two are and why you should care.

R-value and u-factor are actually pretty close to the same thing; they are inverse coefficients of the same phenomenon. R-value is the resistance to heat energy moving through conductance. R-value is not concerned with radiant gains, such as the sun's UV rays passing through a window; the heat gains occur strictly through conduction, molecule-to-molecule, like heat passing from the wall insulation to the actual wall upon contact. In terms of insulation, a higher r-value is desirable, Inversely, we like to see a lower u-factor.

The u-value is the coefficient of heat transfer. So, the r-value's resistance to heat acts directly against the heat transfer of the u-factor. You can convert the u-factor to r-value by dividing the u-factor into 1 (1/u-factor). Similarly, you can get your u-factor from your r-value by dividing the r-value into 1 (1/r-value).

We use these values in load calculations and plug them into Manual J programs. We figure out our BTUs per hour in an equation where we multiply the square feet by the u-factor and the delta t. So, our insulation plays into equipment sizing. Some products also have a rated u-factor. You also need to average out the u-factors if you use multiple materials. (Note: sometimes, manufacturer u-factor ratings are not entirely accurate.)

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Friction Rate and Duct Design w/ Dr. Bailes Nov 21, 2018

This episode is very exciting to me because we get to have Dr. Allison Bailes on the show. Today, he shares his knowledge about friction rate and duct design. Allison got his start teaching college-level physics before getting into the building design industry.

If you have a forced-air system that blows heated or cooled air through a duct system, that blower creates a pressure difference. Some of the pressure is used up on the filter, registers, and dampers, so you will see pressure drops. Anything left over is the available static pressure, which pushes air through the ducts. When you do a duct design, you must account for pressure drops and your blower's static pressure rating.

When designing a duct system, you want to minimize friction as much as possible. Counterintuitively, you want a high friction rate. Friction rate refers to the availability of static pressure compared to friction provided by the effective length, not the total amount of friction. Fittings significantly impact your total effective length. By extension, fittings can have a major impact on friction. In flex duct designs, the turns add additional resistance.

Oversizing often happens due to poor load calculation. While you increase capacity with an oversized system, there are plenty of drawbacks. The capacity will rarely match the load, you may spend too much on the equipment, have ineffective dehumidification, and you will deal with short cycles, which lead to comfort problems.

Allison and Bryan also discuss:

Home energy ratings
Equivalent length and total effective length
Flex duct design
Seasonal runtime
Surface area challenges
Unconditioned spaces
Filtration

To find out more about everything Dr. Bailes has to say about building performance and duct design, visit his site at: https://www.energyvanguard.com/blog

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Critical and Triple Point w/ Rusty Walker Nov 15, 2018

Rusty Walker with Hill-Phoenix comes on and talks about CO2 triple and critical points. He also covers some best practices for refrigeration techs working with CO2.

The triple point is the temperature and pressure at which a substance can exist in all three phases of matter. CO2 has a very high triple point, and CO2 refrigeration equipment can reach its triple point during operation, unlike most other refrigerants. Solid CO2 is dry ice, and it sublimates by becoming a gas and bypassing the liquid CO2 phase under low-pressure conditions. Therefore, the relatively high pressure applied in a CO2 refrigeration system keeps the refrigerant in a liquid state. We want to avoid reaching the triple point because solids can cause restrictions.

The critical point is the point at which a substance becomes a supercritical fluid and loses its pressure-temperature relationship due to densities equalizing. CO2 has a low critical point, only 87 degrees Fahrenheit. So, CO2 refrigeration systems will have supercritical or transcritical CO2 in their systems. You cannot calculate superheat under these circumstances, and you cannot condense supercritical fluid. So, you need to send the supercritical fluid through a gas cooler to reduce the temperature before it can change state.

Critical and triple points are important to keep in mind when working on a CO2 system. You want to control pressure to steer clear of the triple point and understand the necessity of gas cooling when dealing with supercritical fluid. Remember: all of the basic laws of thermodynamics still apply.

Rusty and Bryan also discuss:

CO2 leak detection
Bars and pressure conversions
Supercritical fluid as a solvent
Avoiding triple point on a service call
Recommended equipment and practices for working on CO2 systems
Vacuum
Booster system piping and brazing

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #30 - Braze or Solder Anything Nov 13, 2018

In this short podcast episode, we cover what you need to consider before you solder or braze any type of joint in HVAC/R work. We want to give special thanks to Solderweld; you can learn more about their products at solderweld.us.

When you braze or solder anything, you need to know your base metal. The base metal's temperature and composition will determine which type of flux you will use. For example, if you are working with steel, you can't use fluxing agents with phosphorus. Instead, you will need to use high silver rods and a separate flux. Copper rods with phosphorus don't require a separate flux.

The main difference between brazing and soldering is the temperature. When you work with temperatures above 840 degrees Fahrenheit, you're brazing. Anything below 840 degrees counts as soldering. In both cases, you use an alloy that differs from the base metals.

Copper is highly conductive and is one of the most common metals we use for brazing and soldering. So, it is pretty easy to draw the alloy into a copper-to-copper joint because the copper heats easily and evenly. Steel is nowhere near as conductive as copper, so it can be challenging to work with because the heat localizes. So, on copper-to-steel joints, you need to understand the different behaviors of the metals. It's also a good idea to know the melting point of your base metals to prevent overheating.

As we heat base metals, they change color. When those metals get to a cherry red, that's a great range for brazing; don't let the temperature rise or fall much below that.

We also discuss:

Soft solder
Metal expansion and contraction
Copper-to-aluminum brazing challenges and practices
Flux usage and best practices
Alloy-Sol and bonding
Preventing leaks

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Hot Gas Reheat Dehumidification w/ Eric Mele Nov 08, 2018

Eric Mele is back on the podcast. This time, we cover hot gas as a reheat dehumidification strategy with all of the broad strokes you should be aware of.

One common dehumidification strategy is the hot gas bypass; this strategy allows you to operate under low load. Hot gas reheat is when you add discharge heat back to the conditioned space. When you use reheat for dehumidification, you cool for the purpose of dehumidification and then add sensible heat to remove moisture on the coil. So, you don't overcool the space to an uncomfortable level.

Hot gas reheat uses waste heat from the equipment to remove moisture. Using waste heat is not a very efficient process, but it is better than using electricity or fuel to provide a heat source. Common systems that use this reheat system are 100% outside air units and humidity-control applications. Systems that use hot gas reheat can divert refrigerant to a reheat coil or use a dedicated reheat circuit. No matter which strategy the equipment uses, the reheat always happens AFTER the evaporator coil.

Common issues with these reheat systems deal with the modulating valves. These valves can get stuck or end up in a different position than their controls say. You must confirm that the valves are in position. When working with these valves, you may work with DC controls, so that's something to keep in mind if you primarily work with AC circuits/controls. DC-signal sensors can also malfunction, so you have to check your outputs and can usually find a sensor-related problem quite easily.

We also discuss:

Overcooling to dehumidify
Fresh air requirements and equipment
Solenoids
Expansion line
Technician vs. manufacturer training
Confirming valve position
Stepper motors
Tools for circuits
Checking the refrigerant charge

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #29 - 3 Quick Tips to Level Up Overnight Nov 06, 2018

In this short podcast episode, Bryan covers three things you can do to level up and make you a much better tech tomorrow. Everyone will notice your improvement. Also, no matter what level you're on, you can become even better by remembering the following three tips:

1. Use a full-system diagnostic process. Every application should have a full-system diagnostic process, whether you're working on a residential ductless mini-split, a commercial chiller, or a walk-in refrigerator. Instead of focusing just on the primary problem, you'll be much more effective if you assess the entire system. You can also adopt a wide-narrow-wide approach to diagnosis where you start by examining the entire system (for example, look for oil and check the filter). Then, you focus on the main problem at hand and fix it. Before you leave a job, test the equipment and check it over once again to make sure that everything is working as it should.

2. Communicate better. In the commercial sphere, it's a good idea to write up equipment reports that customers can use to help them make informed choices about their equipment. For residential customers, communication is about courtesy. Send a text to let them know you're en route or send a follow-up email. When it comes to dispatch and leadership within your organization, communicate useful and helpful information for them. Report common things that you see in the field so that they can improve at their jobs.

3. Have a closing conversation with every customer. Before you leave a site, check in with your customer to make sure that there's nothing you or your company can do better. When you have these conversations, you show that you care and give the customers an opportunity to provide feedback.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Combustion Analysis w/ Jim Bergmann Nov 01, 2018

In this episode, Jim Bergmann does a deep dive into combustion analysis. He covers everything you need to know to keep a furnace running safely and efficiently.

When you go into a home, one of the first things you should do is perform an ambient CO test to check how much carbon monoxide is in the home. Combustion analyzers can typically measure CO, or you could use a dedicated CO meter. When it comes to checking for spillage, you'll want to make sure you check anything that is connected to an atmospheric draft appliance; these appliances, including water heaters, can create a pathway for CO.

First, you want to make sure everything is working properly before the combustion analysis. Set the fuel pressure according to the manufacturer's specs. Then, you go outside and clock the meter. When you do that, you merely verify that you have the correct gas input to the appliance; figure out how long it takes the one-foot dial to do a single revolution. After you verify the fuel and air, you want to see if you have an adequate amount of draft. Then, you set your temperature rise and verify that your CAZ zone is within the allowable limits.

When we do a combustion analysis, we measure the efficiency of the combustion process, not the overall furnace efficiency (AFUE). Combustion analyzers also help us account for stack losses. When doing the test, you must measure undiluted flue gas and take readings on fuel pressure, excess air, and stack temperature.

Jim and Bryan also discuss:

Fuel pressure and fuel orifice sizing
Fuel heat content
Excess air and condensing
Carbon monoxide thresholds
Stand-by losses
Contaminants
Temperature rise ranges
Net vs. gross stack temperature
Combustion efficiency
Duct leakage
Positive vs. negative pressure exhaust
Cracked heat exchangers
What to do when CO levels are high
AccuTools

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #28 - The Magic Heat Absorber Oct 30, 2018

This short podcast episode is about a simplified way to explain the basic refrigerant circuit to new techs. By explaining a component as an absorber, rejector, increaser, or dropper, you may help lock in the basic idea of absorbing and rejecting heat.

The goal of refrigeration is to remove heat from a place. Whether that place is a grocery case or a house, we're moving heat. The overall function is pretty straightforward, but the components can get a little bit complicated. At Kalos, we've found that HVAC/R apprentices tend to grasp the refrigerant circuit better when they can refer to the components by their functions. We move heat with a combination of heat absorption and rejection and pressure rises and drops.

For example, the compressor is the "pressure increaser," and the metering device is the "pressure dropper." Likewise, the evaporator is the "heat absorber," and the condenser is the "heat rejector."

When we understand that higher energy goes to lower energy, we can understand that the cold refrigerant inside the evaporator acts as a heat absorber. The evaporator coil is lower than the indoor temperature; it can do its job as a heat absorber even in relatively cool spaces. In air conditioning, we try to maximize efficiency by creating the proper temperature inside the evaporator (heat absorber). In many places, that temperature is about 35 degrees (F) below the indoor dry-bulb temperature. Explaining the component in this way encourages technicians to check the space of the temperature and relate it to the evaporator temperature.

The condenser is a heat rejector; it performs the opposite function of the evaporator. So, the outdoor temperature must be lower than the condenser (heat rejector) temperature. Then and only then can the condenser reject its heat to a cooler location.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Do you even CAZ test? w/ Jim Bergmann Oct 25, 2018

In this first part of the two-part combustion analysis series, Jim Bergmann covers CAZ testing or worst-case draft pressure testing in detail. He also explains why it matters to techs and customers. Once again, MeasureQuick will come in handy if you do CAZ testing in the field; Jim Bergmann is working on automating the testing process in his app.

CAZ (combustion air zone) testing will benefit the customer in both safety and efficiency. A proper CAZ test will also likely increase the furnace system's longevity. This test identifies if there is a high potential for flue gas spillage. We want to check if the appliance is installed in a space where it can easily and safely vent combustion gases. Other appliances can potentially give off exhaust, and they may impede a combustion appliance's ability to vent properly.

Worst-case draft pressure testing is a way of making sure that we have enough combustion air in a room for an appliance to operate safely. Some sealed combustion appliances can potentially suffer negative impacts of depressurization, which is dangerous despite the sealed combustion.

First, you want to measure the CAZ pressure with respect to the outdoors. Then, you turn the air handler on and measure that pressure again to identify possible duct leakage. After that, you close the interior doors and measure the CAZ again. Redo all three of these steps to produce the highest negative pressure. You can measure your pressures with a good manometer or the draft gauge on your combustion analyzer; ideally, your tool's resolution will read tenths of Pascals.

Jim and Bryan also discuss:

Pressurization and pathways
Radiant heaters and other appliances
Disconnected supply
Sealed and unsealed base pans
Exhaust pipe ventilation
Temperature-draft relationship
Water heaters
Resolution, accuracy, and precision
Measurement tools

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #27 - Commissioning Mindset Oct 23, 2018

In this short podcast episode, we talk about the commissioning mindset and what it REALLY takes to set up and commission a new system properly. We commonly check airflow and the refrigerant charge during commissioning.

There is a difference between mere startup and commissioning. When you commission a system, you ensure that it is working according to design. Think about how the system lines up with the manufacturer's specs and how appropriately it fits its application. In Florida, our designs typically maximize latent heat removal, so we want our systems to run optimally by those standards. We have to check sensible and latent capacity to avoid short-cycling and maximize customer comfort.

When comparing your equipment operation to the manufacturer's specs, you'll want to check the charge. You can check the suction pressure, outlet air temperature, and weigh in the charge with a proper scale. You should test the system to make sure that you don't have any leaks from the factory and that Schraders aren't causing any leaks.

Ductless units can be tricky, as there may seem to be little to check. However, you can certainly weigh in the charge and check your pressures to make sure that the unit is running well. You can even check the ductless system's delivered capacity as part of the commissioning process.

Communication with your installers is key. Tell the installers what your targets are so that they can make sure that the system delivers on the contractor's promises. Show your installers how to take the measurements so that they can confirm the operation.

Other procedures that are vital to the commissioning mindset include balancing the ventilation and ensuring that air moves through the supply and return vents correctly. The goal of commissioning is to make sure we deliver on our promises.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

3 Flavors of CO2 w/ Rusty Walker Oct 18, 2018

In this podcast episode, Rusty Walker from Hill Phoenix talks us through the three most common types of market CO2 systems and how they work: secondary, cascade, and booster.

Carbon dioxide (CO2) is one of the oldest refrigerants; it is a natural refrigerant that came about when toxic refrigerants like ammonia were common. In the 1980s, we began to rediscover the benefits of CO2 in market refrigeration, including its high latent heat capacity, low costs, and low global warming potential.

Secondary systems use an HFO or HFC on top, which acts as the primary system and helps discharge heat. These systems have large receivers with both liquid and vapor CO2, and they resemble glycol systems quite a bit. The actual CO2 side of the system moves a lot more heat than the primary system alone; the CO2 side absorbs heat from open cases on the sales floor.

Cascade systems are two complete refrigeration systems tied into each other. Like secondary systems, these may use an HFC or HFO with the CO2 system. A heat exchanger exists between the two systems and serves as the evaporator for the upper cascade or the condenser for the lower cascade.

Booster systems have an upper side and lower side. These may have multiple medium-temp and low-temp compressors. They also have a high-pressure control valve. That controller looks at drop leg temperature and pressure to regulate subcooling. These systems also have a flash gas bypass valve that discharges into the receiver or the medium-temp suction line.

Rusty and Bryan also discuss:

CO2 and ammonia
Triple point
Supercritical fluid
Latent heat benefits
Metering devices
Thermal siphon
Heat exchangers and pressure drop
Upper vs. lower cascades
CO2 pressures
Compression ratio
Subcritical and supercritical modes
Adiabatic operation
Climates

You can also contact Rusty by email at rwalker@doverfoodretail.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #26 - Temperature Mistakes Oct 16, 2018

Can you really trust that temperature reading? In this short podcast episode, we talk about some common mistakes techs make when making temperature measurements and what to do about it.

Many heat pumps use heat strips as a source of auxiliary heat. However, it takes some time for the heat strips to integrate with the air. So, your superheat, subcooling, and pressures will look fine on a system that isn't cooling well enough. When you take air temperature measurements in the ductwork, try to get as close to the center of the duct as possible or take a measurement farther down in the duct. Even so, you need to be careful with measurements in the center of the duct on gas furnace systems because radiant heat can give you an incorrect reading. You can also measure a few different points and average them out.

On gas furnaces with a coil on top, the coil can be in visual contact with your temperature probe. In those cases, the coil will absorb some of the heat from your probe via radiant heat transfer, so you could end up with a lower reading. Not accounting for small sources of heat transfer is one of the most common temperature mistakes that techs can make.

When measuring outdoor temperatures, you want to avoid using your probes in the sun. The sun can add radiant heat to your readings when you calculate CTOA, and you will get a high reading. Radiant heat gains also apply when you're working very close to hot, active pool heaters. The thermostat should also avoid being exposed to very high or low temperatures for maximum accuracy.

We also discuss:

Radiant heat gains
Air mixing
Line temperature clamps and copper cleanliness

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Analog & Digital Manifolds w/ James Bowman Oct 11, 2018

James Bowman returns to the podcast to talk about analog vs. digital manifolds. He also explains why both of them may still have a place in the industry.

Pricing is a key difference between analog and digital manifolds. Analog manifolds tend to be less expensive and will suffice just fine for techs who don't require readings with a lot of detail. While digital manifolds will be more expensive, they can also give you more precise, detailed readings. So, digital manifolds have a slight leg-up in terms of resolution as well; these manifolds are generally better for critical-charge or MicroChannel systems.

Learning to take readings on analog manifolds early on may be advantageous for young or inexperienced techs. You learn more about superheat, subcooling, and interpreting readings when you start off with an analog gauge manifold. The process of taking readings on digital gauges is automated; therefore, digital gauges are less effective as learning tools.

If you want to recover refrigerant, you might be better off using an analog manifold. These are less expensive and may be better equipped to deal with the nasty contaminants inside a system. Digital manifolds are more expensive and should not be exposed to contamination if you want them to last a long time.

We often use accuracy and resolution interchangeably, but accuracy refers to the correctness of a reading. Resolution refers to the scale of the measurement. Digital manifolds usually have advantages in both of these areas, as they can usually take finer readings.

James and Bryan also discuss:

Critically charged systems
Charging and recovery
Hoses
Ductless systems
Technological and practical changes in our industry's future
Using probes to take readings
Single-port manifolds
Applications where accuracy is most important
Causes of inaccuracy
Calibrating probes and other tools

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #25 - A Costly Screwup Oct 09, 2018

In this short podcast episode, we share some quick tips about keeping panels and insulation in place to avoid a costly screwup.

Often, technicians will use an impact driver too aggressively. If you feel it begin to clutch, that means that the driver is actually impacting, and that means you're going too far. When that happens, you can strip out the screws, which can be a serious problem on larger equipment. On RTUs and other large commercial equipment, panels can fall off if you strip out those screws, which can be a costly screwup.

So, don't strip out screws. Even if you need to put the screws in by hand or with a regular driver instead of with an impact driver, you'll see better long-term results. On normal drivers, you can also set the clutch so that the driver stops before it can strip out the screw threads.

When panels fall off, the insulation can encounter issues as well. If the insulation peels off, please put it back on. Don't be afraid to use a little bit of spray glue to help mount that insulation to the inside of the panel. After using spray glue, you can finish mounting the insulation with some butyl tape on the edges, which has a heavy-duty adhesive and should last a long time. (Silver tape is okay, but it isn't nearly as strong as butyl tape.)

When panels come off due to screws stripping out, they can blow away in extreme weather. In Florida, we have hurricanes in the summer and fall, so flying panels should be prevented at all costs. In some cases, you can even use a slightly larger screw to replace a missing screw if need be. Self-tappers also aren't the best screws you can use.

Learn more about Refrigeration Technologies HERE.

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Are Refrigerant Additives OK? Oct 04, 2018

John Pastorello, the HVAC chemist, comes on the podcast and discusses refrigerant additives such as acid inhibitors, oil enhancers, dyes, and leak sealants with his knowledge and some things to consider.

Acid neutralizers are refrigerant additives. Oil works best in a slightly acidic environment, and these additives can change the pH of the system. If the pH becomes neutral or alkaline (basic), then the system will not operate as it should. Acid scavengers won't change your pH, but they are usually alcohol-based, which may attack aluminum in your system and make your windings brittle. Instead of relying on acid-reducing refrigerant additives, the best solution is to use and responsibly replace suction driers.

Corrosion inhibitors are also refrigerant additives. OEMs sometimes use these on their own equipment or recommend the usage of corrosion inhibitors. However, these can come with their own set of impurities. These impurities can be even more detrimental if the products come from a foreign market.

Solvent-type products assist oil return by reducing the oil viscosity. However, these solvents can cause the oil to foam and can quiet your compressor down. These foaming agents have no positive effects on your system; the compressor may run more quietly, but solvents have no effect on the amperage.

Leak sealants are other additives. These started in the automotive industry, and manufacturers would void warranties on cars that had leak sealants in their systems. Leak sealants introduce solid particles into your system to patch up a leak. However, we can't actually repair leaks by patching them with fine solids.

John and Bryan also discuss:

Marketing tactics
Additive testing
Solutions for excessively acidic systems
Oil sample analysis and testing for burnouts
Suction drier usage and pressure drops
Diluting corrosion inhibitors
Non-polymer leak sealants

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #24 - Hard vs. Soft Copper Oct 02, 2018

Many technicians use hard or soft copper without thinking about which application is best for which. In this short podcast, Bryan talks about where to use each. He also covers some hanging and strapping strategies.

Residential service technicians typically work with soft copper. Conversely, commercial techs are probably much familiar with the hard variety. Both hard and soft types are good for specific applications.

If you need to work the copper, then the soft type is best for that. You can bend it by hand or with a bender without too much trouble, and it is ideal for flaring and swaging. However, it does not hang well and is not very structurally sound. If you need to hang copper through an attic or light commercial space, then you're really better off with the hard type. The soft kind also doesn't look quite as nice as its hard counterpart when you use it to feed several condensers with a line set.

Hard copper is straight, rigid, and holds up much better than the soft kind when it must be strapped, and it sometimes comes with rubber plugs. Strapping is not a practice that we commonly think about in residential HVAC, but we still need to strap our piping appropriately. We can use Unistrut and clamps to strap our piping correctly. You can bend, swage, and flare hard copper, but you must heat it before you work it; the hard variety can take a lot more abuse than soft copper and is much more durable. You also probably can't transport this type of copper in a van easily, as it can come in very long segments.

Check out Refrigeration Technologies HERE.

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Check out our handy calculators HERE.

How to Make a Flare That Won't Leak Sep 27, 2018

Kevan Mayer with NAVAC comes on and talks all about flaring best practices step by step. From cutting to reaming to torque wrenches, we cover how to make a flare from start to finish. The goal of making a good flare is to reduce leaks as much as possible, especially on ductless units and in commercial HVAC/R.

When you make a flare, you have to make sure the depth is correct and consistent, especially on R-410a systems. NAVAC makes various flaring tools, including fast battery-powered ones, that can help you get a consistent depth on your flares. You can learn more about some of their flaring tools HERE.

You start off making flares by cutting your tubing. Make sure you have a clean, square cut. Using a sharp tool cutter is the best way to make sure that you get that clean cut. Tighten your tool down in increments. Cleaner cuts make deburring/reaming easier.

Assembly lubricants like Nylog and oil are excellent products to help you make a flare if used correctly. You don't want to let the oil or synthetic lubricants drip into the tube. Only use a little bit of these products, as too much Nylog on the threads can also change your torque spec. You can also put these lubricants on the cone of your flare tool.

When assembling a flare, make sure that you follow the manufacturer's specs regarding height and flare nuts. Be mindful of the torque you apply during the assembly. Use a backing wrench and torque wrench for assembly.

We also discuss:

Reaming/deburring practices
Differences in line sets with different refrigerants
Flares in residential and commercial HVAC
Flare gauges
Torque specs and torque wrench usage
Pressure considerations
Leakage, pressure testing, and decay testing

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Chilled Water Air Handlers Sep 20, 2018

In today's podcast, Eric Mele and Bryan talk about chilled water air handlers, their valve configurations, and some key things to look out for.

In a chilled water system, we don't have the traditional evaporator and condenser in our HVAC system. Instead, we merely have a hot coil and a cold coil. We don't work with a direct-expansion refrigerant that changes state. We merely move water. These chilled water systems can be used in residential and commercial applications.

With almost all applications, both pipes will be insulated in the same size. You may also see an actuator on the outside, which impacts water flow and attaches on top of the valve. Chilled water systems can come in a two-pipe configuration or a four-pipe configuration. The supply water on chillers typically runs about 44 degrees (F).

The water loops on chilled water air handlers may have either a two-way valve or a three-way valve. You'll generally see a two-way valve on systems with variable frequency drives (variable water flow). Conversely, three-way valves will typically be on systems with more constant water flow; the pump runs at a constant volume, so the three-way valve acts as a bypass. If you must replace a valve, make sure you use the correct valve for the application.

These chilled water air handlers don't easily allow you to get readings from them. Once you factor insulation in, you may not have access to pressure ports at all. Some larger air handlers may have gauges installed, but they may not be accurate.

Eric and Bryan also discuss:

Insulation
Diverting vs. mixing on three-way valves
VAV system similarities
Line voltage controls and fan speed
Challenges and building maintenance staff
Air bleeds
Actuators

Learn more about Refrigeration Technologies HERE.

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Short #23 - Intangible Soft Skills Sep 18, 2018

In this short podcast episode, Bryan gets feedback on a podcast topic from Andy Holt. Per Andy's request, we discuss some intangible soft skills required to be a top-level technician in the HVAC trade.

Overall, a technician needs to be aware of the people and things in their surroundings. These techs are in tune with their customer's emotions, the pets, and the space where they work. A good technician is thoughtful but has the ability to let things go and not let their bad experiences overwhelm them. Many technicians that fit both of those descriptors are calm and focused by nature, and they are often positive people; happy techs are better communicators with customers.

Eye contact is important in the right amount. Customers want to know that you're paying attention to them. Customers also want to see action; they want to see you physically working on their system and taking measurements. Give the system a thorough check to find the most thorough diagnosis, even if you go into the job with an idea as to what that diagnosis is.

Cleanliness is a way for you to show respect for your customer's home or site. Use drop cloths and wear shoe covers to show that you care about keeping the site clean. Cleanliness is a branch of the overall idea of professionalism. Our image of professionalism is always evolving, but in the present day, you still want to use classy language and avoid looking like a slob. Most of all, professionalism stems from a central concern for the customer; spend less time talking and more time listening.

Organization in paperwork, processes, your work vehicle, and your toolbag is another one of those critical intangible soft skills. You exude professionalism when you are neat and have a structured process to guide you through your work.

Learn more about Refrigeration Technologies HERE.

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Refrigeration Temperature Controls w/ Chris Stephens Sep 13, 2018

Chris Stevens from HVACR Videos on YouTube comes onto the podcast and talks about some refrigeration temperature controls basics. You can check out his YouTube channel HERE.

Although we have temperature controls in HVAC work, we will see slightly different ones in refrigeration work. The biggest difference is really the temperature itself; we're attempting to bring the box temperature down, so we will be dealing with much lower temperatures in refrigeration. The box and evaporator coil temperatures are the most important temperatures to be aware of in reach-in refrigeration, as they directly relate to pressures.

A standard pressure control opens or closes when pressures fall or rise. Your typical low-pressure control will open on a pressure fall and close on a pressure rise. We can use these as loss-of-charge switches or use them with the pressure-temperature relationship as evaporator temperature controls. However, pressure controls can be quite inaccurate. You absolutely CANNOT "set it and forget it" with these controls; you will likely have to make some adjustments, especially if you have long line sets. We also need to consider defrost in our strategies.

Constant cut-in controls are other common control strategies. These are simple controls with a sensing bulb in the evaporator coil that senses evaporator temperature as closely as possible without being a pressure control; they also turn on at a set temperature. These refrigeration temperature controls are quite accurate, but they can be difficult to use properly because they also pick up lots of other vital signs from the system.

Chris and Bryan also discuss:

TD vs. delta T
K-type thermocouple calibration
Wrap-up procedures for refrigeration jobs
Self-defrosting with pressure controls
Constant cut-in control sensing bulb placement
Service gauges
Frost buildup in medium-temperature applications
Digital controls
Controls based on product temperature
Universal and aftermarket controls
Air-sensing temperature controls

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #22 - Mineral & POE Oil Sep 11, 2018

Bryan talks about the differences between mineral oil (MO) and POE oil, the advantages and disadvantages of using them, and when to use them.

Mineral oil (MO) is what we've used for a long time. We like using it because it's very stable; it may have an affinity for moisture, but it is not nearly as hygroscopic as POE oil. Vacuum pump oil is a highly refined mineral oil, and it works so well because it's able to lock in moisture as those non-condensables get sucked out of the system. It is still not much of a solvent compared to POE oil, though.

However, the refrigerant may have a hard time carrying mineral oil through the system. So, pipe size, pitch, and trapping are important considerations when you're dealing with mineral oil.

POE (polyol ester) oil works much better with newer refrigerants, especially R-410a. These new refrigerants can't carry mineral oil effectively, and so they rely on POE oil, which moves with those refrigerants a lot more easily and doesn't just sit in the evaporator coil. Oil should stay in the compressor, but oil loss will happen over time and should move back to the compressor with the refrigerant. POE oil works with new refrigerants, but it also works with R-22. Overall, POE oil is very miscible, which means that it moves with refrigerant very well.

However, POE oil is reactive and acts as a solvent. The POE oil can pick up contaminants a lot more easily than mineral oil, which can wreak havoc on your system. POE oil reacts with moisture to become acidic, which can lead to issues like burnout. (Note: POE oil does NOT react with mineral oil!)

Bryan also covers:

Refrigerant velocity
Oil return
Acid scavengers
Retrofits

Learn more about Refrigeration Technologies HERE.

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Small Refrigeration Maintenance Procedure Sep 06, 2018

Eric Mele returns to the podcast to discuss quality cleaning and maintenance procedures for small refrigeration systems. These small refrigeration systems include reach-in refrigerators and open-air cases on grocery sales floors.

Filthy condenser coils are problems in many HVAC applications, but they're exceptionally nasty in some small refrigeration applications; proximity to food residue (grease, sugar, etc.) makes condensers get dirty quickly. Use plastic-bristle brushes to clean the bulk of the soil on the coil; you may also use shop vac extensions or even pull out coil cleaner in some cases. If you use coil cleaner, be sure to protect components from the cleaner. When doing maintenance on a small refrigeration system, try to prepare for the cleaning ahead of time.

Drain cleaning and maintenance on small refrigeration systems is quite similar to other commercial systems. Drain backups are also a major cause of callbacks. It would also be wise to check that your drain pan heaters are working. You may have to use hot water in low-temp applications, as moisture may freeze on the coil. If you can't use hot water, you may consider using blower fans to avoid freezing (or just letting the unit defrost if you can).

Different climate zones have unique issues. For example, in Florida, we tend to have issues with voltage from the utility companies and constant heat. So, we need to test capacitors because they fail quite often.

Overall, the philosophy of good maintenance is to "do no harm." Astute observation skills are also very helpful when you do maintenance, as you'll be checking many components.

Eric and Bryan also discuss:

Ambient temperature ratings
Radiant heat in grocery settings
Using compressed nitrogen for cleaning
Food prep areas
"Dry" steam cleaning
What if the box is not meeting temp?
Cutting bleed resistors
Unnecessary maintenance procedures

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 21 - Leak Detectors Sep 04, 2018

Bryan talks about the top refrigerant leak detectors, the best refrigerant leak detection practices, and some good leak detection tips.

Leak detectors require some flow through them. Otherwise, they won't detect leaks. So, these tools have small pumps inside of them to move air through them for sampling. Leak detectors also require some time to warm up, so keep that in mind when you approach a job.

One type of leak detector is a heated diode (sometimes called a heated pentode). It is a heated electronic leak detector that takes a sample and analyzes it within. Infrared detectors also exist, but they require you to move the tool consistently; these tools constantly recalibrate themselves, so you can't hold it still while you're using it to locate a leak.

Once you confirm that you have flow, you need to determine that the detector is actually working. Make sure that your detector can pick up tiny leaks, not just large ones from cracking open a can of R-410a. So, we recommend using leak references that you can use to test your detector. One of those references is a leak test vial.

Some leak detectors have a tip filter, which prevents contaminants from getting into the system. Make sure that your detector has a filter and that you change it regularly. You don't want water or other contaminants getting into your leak detector and breaking it. Another surprising contaminant is leak bubbles; these bubbles can also set off a leak detector, so be careful to manage your order of operations to avoid false positives.

These tools work best if you store them in clean, dry places. It is also a good idea to keep a backup in case your main leak detector breaks or loses accuracy.

Learn more about Refrigeration Technologies HERE.

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Vacuum Pump Basics w/ Kevan Mayer Aug 29, 2018

How does a vacuum pump work? When should you change the oil? What does that oil do anyway? Kevan Mayer of NAVAC comes on the podcast to answer these questions and more in this episode.

Vacuum pumps help remove moisture and non-condensables from the system. Moisture can freeze at temperature drops in the system, and it can block refrigerant flow to the system. Moisture can also combine with POE oil to become acidic, which causes burnouts. A vacuum pump uses an impeller to bring a system under negative pressure. Many of these pumps are two-stage pumps, meaning that they have multiple chambers that push the contaminants through the pump before they get discharged into the atmosphere. As with other tools, it is a good idea to confirm your vacuum pump's operation regularly to make sure you can use it effectively.

Vacuum pump oil is a type of highly refined mineral oil and should be clear. It is hygroscopic and attracts moisture, like POE oil, so you need to take care to avoid contamination. This oil both lubricates the vacuum pump and absorbs incoming moisture from the system. It's a good idea to replace your vacuum pump oil every job when you have a small pump; you may even need to change it multiple times per job. Larger pumps will typically handle a few jobs before you need to change the oil. In any case, change the oil if it starts looking amber or milky.

Kevan and Bryan also discuss:

Gas ballast valves
Vacuum gauges and micron gauges
Changing gaskets in hoses
Proper oil disposal
Vacuum pump size
Vacuum pumps with solenoids
NAVAC pumps and features
Dedicated vacuum hoses
Standing vacuum tests

Check out NAVAC at navacglobal.com, or look for their products at trutechtools.com.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #20 - Tips for Service Valves Aug 28, 2018

In today's short podcast episode, Bryan covers some tips about HVAC/R service valves and caps for new technicians. While service valves may seem simple, there are some things you should know about them before you handle them in the field.

Before you connect your gauges, ask yourself if you even need to connect gauges. If you've already benchmarked the system and know what to expect, then you may be able to suffice with line temperatures. If you have a system with caps or Schrader cores and need to hook up your gauges, be careful not to cover any leaks in the cap or Schrader. You could potentially miss a leak on a cap or Schrader, so be sure to inspect those before you hook up your gauges.

Service valves require gentleness and care when you take caps off and on. You don't need to overtighten caps and Schraders, as they mostly come together at an O-ring fitting or with a flare; check to make sure that you're using the correct caps and that those caps have their proper seals, if applicable. If you need to use a thread sealant, a dab of Nylog comes in handy. If you're too hard on it with a wrench, you could break the entire service valve.

When you braze in or around a service valve, you'll want to protect it from heat. One of the best ways to do that is to tie a wet rag around it or use Refrigeration Technologies WetRag heat-blocking putty. (Remember, leave the Schraders out while brazing!) Overall, you'll really need to think about protecting that service valve from damage any time you work on it.

Learn more about Refrigeration Technologies HERE.

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Hard Shut Off TXVs Aug 23, 2018

Jamie Kitchen returns to the podcast and talks all about hard shut off TXVs/TEVs. He discusses bleed and non-bleed valves and why the TXV type matters to your compressor.

When it comes to TXVs, there are two main types: bleed and non-bleed. The former may be referred to as a bleed TXV, and the latter may simply be called a TXV. However, OEMs may refer to TXVs as a "hard shut off TXV" (HSO), which is a non-bleed TXV.

The core difference between bleed and non-bleed TXVs is the equalization speed. That equalization speed affects how your compressor runs; equalizing the system reduces the pressure differential that the compressor will have to overcome on startup. Non-bleed/hard shut off TXVs may cause the compressor to draw locked rotor amps because the pressures did not equalize. To mitigate that issue, you can put in a start cap and relay on the compressor or replace the valve with a bleed TXV.

The main purpose of hard shut off TXVs is to prevent refrigerant migration and flooded starts when the system is off. The non-bleed TXV does not permit equalization, which builds pressure and but keeps refrigerant in the condenser, not the evaporator. Although the compressor will have to overcome more pressure upon startup, it will be less likely to fail due to a flooded start. However, some manufacturers may recommend using a hard start kit to overcome that pressure if you use a hard shut off TXV (even on scroll compressors!).

Jamie and Bryan also discuss:

Non-bleed TXVs on scroll compressors
Pressure rising and falling throughout the system
Opening/closing forces
Superheat spring
Liquid refrigerant migration
Shutting off the suction line vs. using a liquid line solenoid valve
Proper equipment sizing and short-cycling
Charging with bleed vs. non-bleed TXVs
Energy benefits

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 19 - Superheat, Evaporator vs. Compressor Aug 21, 2018

In today's podcast, we cover why both compressor and evaporator superheat matter. We also address some common confusion related to each.

Evaporator and compressor superheat are two different readings that give you different indicators about the system's health. When you look at evaporator superheat, you see how far you feed boiling refrigerant into the evaporator coil. You don't want to overfeed your evaporator coil and risk flooding your compressor. However, you also don't want to starve your unit and reduce suction pressure. You'll want to stay between 5 and 14 degrees (F) of superheat at the evaporator outlet on typical A/C systems.

On TXV systems, we can control superheat at the evaporator outlet. Evaporator superheat is the reading that helps you optimize your capacity. Increasing it will decrease your evaporator capacity, as the evaporator coil won't be fed as much refrigerant. The lowest possible value is your best bet for maximizing efficiency and capacity.

Compressor superheat can be measured before the compressor. When you know that value, you can predict how hot your compressor will be when it runs. The temperature can increase from the evaporator outlet to the compressor inlet. Poor insulation in close proximity to the liquid line can be a cause; heat can transfer from the warm liquid line to the cool suction line. Our goal is to minimize heat gain in the suction line, so we want to insulate our suction lines and keep them as short as possible. However, you don't want the compressor superheat to be so low that you end up flooding the compressor.

In most cases, you should check both values to evaluate the heat gains or losses in your suction line.

Learn more about Refrigeration Technologies HERE.

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Pulling a Vacuum 2.0 w/ Jim Bergmann Aug 16, 2018

In today's podcast, Jim Bergmann joins us to talk about evacuation. He discusses pulling a vacuum, conductance speed, microns, core removal, decay rate, and all that other nerdy vacuum stuff. Jim has helped develop some new BluVac hoses with AccuTools, and he's here to explain why we need those. He also explains why we need to be more educated on evacuation.

While we have many good hoses today, we still have a way to go when it comes to moisture removal. Jim Bergmann has seen the need for more durable hoses that perform better when there's moisture and acids in the system. Pulling a vacuum that makes the system dry is crucial for that equipment's longevity. You cannot over-vacuum a system, so the deeper vacuum you can make, the better your evacuation will be.

Evacuation often takes place on new pieces of equipment, and some people worry that deep vacuums will compromise the oil quality of those new systems. That is actually not a real issue to worry about during evacuation, and it's a piece of misinformation that makes people misunderstand the importance of evacuation. Not enough people understand how evacuation works, and that is how misinformation and distrust around evacuation spread throughout the HVAC industry.

Evacuation best practices come down to the materials you use. We'd like to use a dedicated evacuation rig with the highest possible conductance speed. So, to achieve that, you'll want as few fittings/connections as possible and wide, short, high-quality hoses that are impermeable and leak-free. Remember to remove all Schrader cores and use your micron gauge away from the pump. Pull the vacuum down as deep as you can get it and do a decay test.

Bryan and Jim also discuss:

Degassing and dehydration
Best evacuation technologies of yesterday and today
Evacuation education gap
TruBlu hoses
Pressure, density, and air "thickness"
Moisture adhesion
Behavior of water
Hose ratings
POE oil and moisture

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 18 - Can You Freeze Water in a Vacuum? Aug 14, 2018

In today's short podcast episode, Jim Bergmann and Bryan answer the age-old question: Can you really freeze water in a vacuum by pulling down too fast? Is that a problem? What should you do about it?

Here is the short answer: NO. You CAN'T freeze water in a vacuum in a typical residential A/C system.

First of all, you would need to have water in the system to freeze water in the system. We typically don't see large amounts of water in JVAC systems, but there could be moisture in the evaporator coil in refrigeration. Coupled with the very low temperatures, you could see freezing under vacuum in those systems.

However, you will almost never see freezing moisture under vacuum in residential comfort cooling. On top of that, you would need to have enough water to freeze, not even considering the vacuum speed. We cannot achieve a vacuum that would cause that much water to freeze in a system.

When you perform a decay test, the pressure rise will taper. (If it doesn't rise, then you have a leak.) When the pressure tails off, you've likely come across moisture in the system. You can usually remove that moisture without having to worry about freezing; that moisture will merely exit the system under vacuum, and it typically will not freeze.

But what about water in a normal, non-HVAC vacuum? Can you freeze water in a vacuum then? YES.

The water would vaporize before it freezes, and it would sublimate off very quickly on most vacuum rigs. You can check out this article and video to watch an experiment in action.

Learn more about Refrigeration Technologies HERE.

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What We Learn From HVAC/R Trade School Aug 09, 2018

In this episode, we talk with two techs recently out of trade school. We get their perspective on their trade education and how it compares to the field. Jeremy and Blake have been kind enough to share their experiences with us and give some advice.

Schooling undoubtedly gives technicians a leg-up once they got into the field. However, the knowledge you gain isn't all practical. Bookwork is still important for a solid foundation in theory, and it would likely benefit a lot of training programs. Bookwork, like trade school itself, is a good precursor to the hands-on material in the field. It also helps to do your research about classes you need to take and to see if a degree is more advantageous than a certificate or vice versa.

Your education won't end upon getting that certificate or degree. In the field, you will learn something new every day (and not in the air-conditioned classroom!). A lot of your familiarity with tools will come from working in the field. However, in trade school, you will learn best practices that you may not learn from other workers in the field.

When you enter the field, invest in your tools. You will work with classroom equipment, but once you enter the field, you will have to develop your own arsenal of tools—research new tools and set aside part of your paycheck to invest in your toolbox.

In many ways, this is the trade with homework. You have to want to learn to be successful in this field. Every day, you will come across new problems that require more knowledge, and nowadays, you have plenty of access to online sources of information to help you tackle difficult problems.

Well-rounded techs come from a solid education and apprenticeships with competent senior techs.

Learn more about Refrigeration Technologies HERE.

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Short 17 - MicroChannel Aug 07, 2018

Bryan talks about MicroChannel coils, what issues could happen with them, and what the best practice is to clean them.

MicroChannel coils are kind of like car radiators; they have a small, honeycomb-like channel, and the sections that go between the crisscross fins carry refrigerant from the front surface to the back surface. These coils have a bit of a bad reputation. The refrigerant flows close to the surface of the coil. When the MicroChannel suffers damage, these coils can leak much more easily than other tube-and-fin coils. The channel is also more likely to be exposed to the elements and cleaners, where they can suffer from corrosion. Both alkaline and acid cleaners can cause corrosion on these coils.

The manufacturers usually advise against using a cleaner. However, we know that not using cleaners can be unrealistic. When you need to clean MicroChannel coils, you should use a cleaner that is not heavily alkaline (and certainly NOT acidic!). Refrigeration Technologies' Viper cleaner is an excellent product for cleaning coils without causing damage.

These small coils also hold less refrigerant than other coils. You have less flexibility with the charge, and the charge is so much more critical. A seemingly insignificant charge deviation on a normal system will have a greater impact on a system with these coils. You also have to use a chart to determine your subcooling on a spectrum to set your charge; the subcooling is not a fixed value. If you have MicroChannel coils shipped in, they may also not come with their full charge because they simply can't fit the refrigerant. Pump down is also dangerous in these coils. You can build up too much pressure and cause the coil to burst.

Learn more about Refrigeration Technologies HERE.

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Water Source - The Water Side w/ Eric Mele Aug 02, 2018

In this episode, Eric Mele dives into the world of pumps, controls, cooling towers, and everything else related to the water side of a water source heating and cooling system. Many of these systems are water-to-water setups that use heat exchanges for heat transfer. You can listen to an introduction to water source heat pumps HERE.

A cooling tower is where we reject the heat that we put into water loops. Most of these towers are of the induced-draft variety, meaning that they have fans drawing/blowing air through them. Some cooling towers are "wet" towers, where water is open to the fluid you're working with, so some of that water is lost to evaporation. Contamination can be an issue with the wet open-type towers, but strainers, chemicals, and proper planning (for location) can prevent contamination. Dry towers do not need constant refilling and need fewer precautions against contamination.

These water-to-water systems use centrifugal pumps to push water through the system. These circulate water molecules, NOT compress them. Water source heat pumps get their heat from boilers, not the outdoor air in most air source heat pumps. When you have gas boilers, you have to think about your typical furnace concerns, including combustion air and carbon monoxide.

Air can sometimes circulate with the water, and you'll want to minimize that as much as possible, such as via air bleeds. These air bleeds may have ball valves that you can use to purge a lot of air. Other systems may not have air bleeds, but you will still need to get air out of the system.

Eric and Bryan also discuss:

Makeup water float assemblies
Strainers and cleaning procedures
Heat exchanger configurations
Water sources and quality control
Water treatment
Couplings and alignment
Boiler configuration
Bypass valves
Expansion tanks
Water source heat pump controls
Variable frequency drives
Aquastats

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 16 - Air Velocity is Useful Jul 30, 2018

In this short podcast episode, Bryan covers how to measure air velocity directly at a return or supply and what those readings tell you.

Since many techs like to focus on CFM and static pressure readings, they can neglect air velocity in their measurements. Air velocity is the speed at which the air is moving. Conversely, static pressure is the force of the air against the sides of the ducts, and CFM is the air volume. We measure air mass in pounds (in the USA); when air is denser, you will have more pounds, but the volume will stay the same.

We primarily measure air velocity with a vane anemometer. Air moves through the vane and spins it, which informs the anemometer. That anemometer then gives you the reading. While airflow is the ultimate measurement, it is much better to take velocity measurements than none at all. Velocity can help you determine the CFM, but that requires knowledge that some techs don't have or are simply unwilling to apply. You need to know the size of the intake and have knowledge of the open/free area of the vent.

Velocity can help you determine how much throw you need to reach a certain distance. Velocity is a measure of feet per minute and can be applied to distance variables like throw. However, register sizing needs to come before measuring velocity. Velocity helps you figure out your throw and register sizing without relying on CFM measurements. Velocity can also help you identify noise issues, with higher velocities indicating noisier ductwork.

To reduce air velocity in cases where you have too much, you may need to use a balancing damper to throttle it back.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Intro to Water Source Heat Pumps w/ Eric Mele Jul 26, 2018

In today's podcast episode, Eric Mele walks us through the components of water source heat pumps, how they work, and what to look for. Water source heat pumps use water to transfer heat to and from the outdoor unit; the water takes the place of outdoor air in an air source heat pump.

These units have heat exchangers and water lines, but they otherwise operate exactly the same as any other heat pump. These units have reversing valves, which are commonplace on heat pumps, and they are energized by a typical O call. Water source heat pumps almost never have defrost boards, unlike air source heat pumps. However, these units may also have auxiliary heat, such as electric heat. Capillary tubes are the typical metering devices on water source systems; the refrigerant flow can reverse through the metering device and doesn't require a second metering device, unlike air source heat pumps. Some larger water source systems may have TXV systems, and the bulb goes very close to the compressor.

Water temperature will affect the cooling capacity of water source heat pumps. However, pressure and flow rates are also important factors to measure. You can measure the temperature differential across the heat exchangers and liquid line temperatures to determine if you have water flow issues.

The refrigerant and water counterflow; the water and refrigerant move in opposite directions. Piping quality is an extremely important concern in a water source heat pump. If the piping fails or is supported poorly, all of that water can flood out and cause a lot of damage.

Eric and Bryan also discuss:

Measuring water pressure
Scale buildup and neutralization
Capillary tube strainers and restrictions
Brazing
Fasteners

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 15 - Testing Capacitors, A Practical Approach Jul 24, 2018

In this short podcast episode, Bryan Orr discusses the best practice methods for testing run capacitors in the field.

We understand the capacitor to be a voltage storage device. We can benefit from comparing the capacitor to a balloon that inflates and deflates with electrons as the alternating current changes (60 times per second). A capacitor causes a phase shift and allows there to be current on the start winding. So, when a run capacitor fails, you won't have current on the start winding.

The old-fashioned way of testing a run capacitor was to take an ohmmeter and charge/discharge the capacitor. Nowadays, we have capacitor testers, and many multimeters also have capacitance testers. Capacitance is merely a mathematical equation that you use when you compare the amount of voltage to the amount of current entering and leaving.

A good way to test a capacitor on a running system is to test it under load. You take the amperage of the wire feeding the start winding and multiply it by 2652. Then, you divide that product by the incoming voltage across the capacitor to get the capacitance. While this method is probably the most practical, it still has a caveat; some meters may have a hard time getting a proper amp reading on the start winding. So, tool accuracy will also determine your success when testing capacitors under load. To increase accuracy, make sure your wires are isolated from others. Under-load testing may also be unsafe in some cases, such as with a blower capacitor.

Testing with the system off is called bench testing, and it is slightly more accurate but does not represent under-load conditions. It will be more practical than under-load testing if the system is already off or if it is unsafe to test the capacitor under load.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Seasons of HVAC Jul 19, 2018

In this episode, Bryan Orr talks about how the seasons affect our HVAC work and how to manage stress during the busy season.

If you work in the trade, you will notice that we have busy and slow seasons. If you own a business, you understand the pressure that you're under to serve the community during those times. Hiring and training people for the busy seasons is difficult and may not be feasible for many companies. Fortunately, the busy season can bring out the good in other people who want to support their coworkers and community.

The summer tends to be the craziest season, especially in the hot southern states. We work long hours and sometimes deal with angry or frustrated customers. We definitely experience times when our bodies don't feel like they can take the workload. The summer is a hard time, but that hard time also gives us a chance to build our character and take pride in our work.

We remember those hard times during the cool season, winter. That's the time for Christmas parties, bonuses, and taking it easier around the shop.

The seasons of our work are like the seasons of our lives. We have times where we have to work extremely hard and others when we don't need to. We got into the trade because we wanted to do something that helps others in the real world. In our work, we build up that grit and strength of character so that we can appreciate the less physically demanding days later, especially when we get into management, but we may never truly give up our work completely. HVAC technicians keep that strength of character and wisdom from the hard seasons, and they hold onto those throughout their lives.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 14 - The Voltage Drop Tool Jul 17, 2018

In today's short podcast episode, Bryan discusses the voltage drop measurement tool, also commonly known as the voltmeter. You can also find this voltage drop tool on multimeters. You use them to check voltage drops, NOT the actual voltage.

We get voltage values from a potential difference. So, we check for these differences via voltage drops. For example, you can determine if contactor pitting or carbon buildup is problematic by measuring the voltage across contact points. Your meter will read the voltage drop.

We don't often deal with intentional series circuits. However, we can see unintentional series circuits when switchgear or wiring adds more resistance than it should. The voltage drops when that happens. You can also use a voltmeter to locate an open circuit; when you no longer see voltage as you walk through a circuit, you can determine that you have found an opening.

An HVAC system with low current may have a cumulative voltage drop, which is the total drop of all the voltages in the system, including the crankcase heater and compressor windings. Kirchoff's second law helps explain the behavior of the voltage in a system; the law states that for a closed-loop series path, the algebraic sum of all voltages around any closed loop is equal to zero.

Any time you use a voltmeter, your two leads communicate the voltage drop from one lead to the other, whether those are across contactors or different points on the same wire. When finding an undesigned voltmeter is most effective when used under load. You will see a massive voltage drop when you use a voltmeter under load; otherwise, you will see a much smaller voltage drop.

Check out Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Commercial vs. Residential w/ AK HVAC Jul 12, 2018

In today's podcast episode, we have a conversation about the pros and cons of commercial vs. residential HVAC with Andrew Greaves. (You may know him as AK HVAC on Youtube. Check out his channel HERE and his comedy channel, HVAComedy, HERE.)

In many cases, young people don't know if they want to go into commercial or residential HVAC, or residential techs may think about getting into commercial HVAC. Commercial HVAC may include RTUs, chillers, market refrigeration, or industrial refrigeration. Commercial HVAC/R also includes a lot of control systems. By comparison, residential HVAC almost exclusively deals with comfort cooling.

Even though it may seem as though commercial HVAC requires more specialized schooling, that isn't necessarily the case. Schooling will especially help with commercial HVAC, but it's not required. The desire to learn is much more important than schooling. (Be willing to unlearn your bad habits, too.) If you enjoy working on large equipment and machines, commercial HVAC may be right for you.

Hours are also a bit different in commercial vs. residential HVAC. In many cases, commercial HVAC still has on-call time, and the hours may be slightly more regular than residential HVAC. (However, some facilities like hospitals may require work at irregular hours.)

If you wish to become an entrepreneur, you'll probably have more success with residential HVAC. The business models are very different, and you'll have more freedom with pricing when you start up a residential business. Commercial work is process-oriented per the customer, and there is a lot of negotiation that goes into a contract. (You'll also be more likely to stumble across lawsuits in commercial HVAC.) If you want to start up a business or have an entrepreneurial spirit, then residential HVAC might be right for you.

We also discuss:

Mechanical/technical aptitude
People skills
Commercial vs. residential shops
Service contracts
Corporate environments
Commercial HVAC technologies
Commercial HVAC specializations
Profitability as a tech vs. a business owner

Learn more about Refrigeration Technologies at refrigtech.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 13 - 3 things the condenser does Jul 10, 2018

In this short podcast, Bryan covers three things that the condenser does. He also explains where those things happen and what those they mean in terms of system operation.

The evaporator coil does two things: boiling and superheating. However, a condenser does three things: desuperheating, condensing (changing state), and subcooling.

Desuperheating occurs early on in the condenser, at the top. Refrigerant enters the condenser as a highly superheated vapor. Even though we have a few degrees of superheat in the suction line, the discharge line's superheat is a lot greater. (For context, the suction line will feel cold to the touch, but the discharge line will burn you.) The compressor skyrockets the superheat through the heat of compression and sends that refrigerant to the condenser via the discharge line. So, desuperheating reduces the temperature from 160+ degrees to the saturation temperature, about 100 degrees.

In the middle of the condenser coil, the refrigerant stays at saturation. However, it continues rejecting heat. That is because the refrigerant is undergoing a phase change from vapor to liquid; it rejects heat in the form of latent heat even though the temperature stays the same. Once all of that latent heat has been rejected to the air, the refrigerant becomes fully liquid. Then and only then can the refrigerant start to drop its temperature.

The temperature of the liquid refrigerant drops at the bottom of the condenser coil. We call that process subcooling. Subcooling refers to the temperature of a liquid below the saturation point. For example, if the saturation point is at 100 degrees but the liquid refrigerant is 95 degrees, you will have 5 degrees of subcooling. In general, a common subcooling range is 8-14 degrees.

Learn more about Refrigeration Technologies at refrigtech.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short 12 - The First 4 Rules to Learn Jul 05, 2018

Many techs have said, "That's the first thing you should have learned in school." In today's short podcast, Bryan talks about the four rules that have his vote for the first things to learn in school.

These four rules don't just apply to HVAC work; they apply to science and the world as a whole. They describe how the forces in our world work in our HVAC careers and our everyday lives.

The overarching theme of these rules is that high goes to low. Gravity is the prime example of this rule; if you drop something from a high place, it will fall to a lower place. There is a potential energy difference between high and low, whether you apply that to a ball rolling down a hill, voltage, or a sine wave.

The first rule is that high pressure goes to low pressure. The compressor applies lots of pressure to the low-pressure refrigerant inside of it.

The second rule is that high temperature goes to low temperature. We transfer heat from the inside of the house to refrigerant inside the evaporator coil. (Remember: temperature is an AVERAGE measure of molecular activity.)

The third rule is that high voltage goes to low voltage. Electrons move from the higher energy state to the lower energy state.

The fourth rule is that high humidity goes to low humidity. For example, two air masses with different humidity contents can be separated by a cloth. The higher-humidity air mass will diffuse some of its moisture across the cloth to the lower-humidity air mass. This process creates a stasis across the two air masses.

Everything in the world tends towards equilibrium.

Learn about Refrigeration Technologies at refrigtech.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Coil Cleaning with John Pastorello Jul 03, 2018

In this episode, we speak with the founder of Refrigeration Technologies, John Pastorello. He also tells us all about chemicals, cleaners, and HVAC coil cleaning.

John Pastorello started out working as a chemist before becoming an A/C installer. He initially planned to return to a lab job, but he found his niche in HVAC work. He took his chemistry experience to his HVAC work to develop better chemical products. It all started with his decision to make a better leak detector fluid (Big Blu). However, John knew that you can't build a company around one product, so Refrigeration Technologies was born.

An ideal condenser coil cleaning starts with having the correct dilution ratio. There is a bell curve of effectiveness, and using too much cleaner can be as ineffective as using too little cleaner. Typically, we can optimize soil removal with a dilution of one part cleaner to five parts water. You can pre-rinse with enough pressure to "punch through" the coil. Then, you can apply the foam detergent. Foam guns can make it easy for soil molecules to bond to the detergent. John recommends starting at the bottom and working upwards, keeping the foam gun close to the condenser the entire time. Give the detergent some time to penetrate through the soil, and then rinse. Repeat the process for maximum effectiveness, upping the dilution ratio this time.

Evaporator coils can develop a unique problem: biofilm. Very few cleaners attack that protein biofilm. EVAP+ coil cleaner contains enzymes that can digest biofilm and remove it over time.

John and Bryan also discuss:

Acid vs. alkaline products
"Green" products and performance
Cleaning products and bodily hazards (itching, scarring, etc.)
Foam cleaning
Coil brushing
Testing new chemicals
Chlorine corrosion on aluminum oils
Pan and drain cleaners

Visit the Refrigeration Technologies website and learn more about their products at refrigtech.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Danfoss ERC213 Parameters Review Jun 27, 2018

In today's podcast episode, Jonathan Romberg comes on to discuss how the Danfoss ERC 213 works and reviews its parameters with us.

Timestamps: 10:30 – Key Features

10:41 – Voltage Protection

10:56 – Compressor Protection

14:43 – Applications

15:15 – App 0 No predefined application

15:28 – App 1 Medium temperature ventilated refrigeration units with timed natural defrost

15:52 – App 2 Medium temperature ventilated refrigeration units with timed electrical defrost

16:03 – App 3 Low temperature ventilated refrigeration units with timed electrical defrost

16:13 – App 4 Medium temperature ventilated refrigeration units with electrical defrost (by temperature)

16:26 – App 5 Low temperature ventilated refrigeration units with electrical defrost (by temperature)

16:37 – App 6 No predefined application with a simplified list of parameters

19:45 – Sensors 22:06 – Basic Groups of Parameters 23:09 – r-- Thermostat

23:12 – r00 Temperature setpoint

23:24 – r01 Differential

23:32 – r02 Min setpoint limitation and r03 Max setpoint limitation

24:02 – r04 Display offset

25:19 – r05 Display Unit (°C/°F)

25:33 – r09 Calibration of Sair

25:47 – r12 Main switch

27:17 – r13 Night set back

27:48 – r40 Thermostat reference displacement (offset temperature)

28:30 – r96 Pull-down duration and r97 Pull-down limit temperature

29:06 – A-- Alarms

29:13 – A03 Delay for temperature alarm during normal conditions

30:15 – A12 Delay for temperature alarm during pull-down/start-up/defrost

31:00 – A13 High-temperature alarm limit (Cabinet/Room)

31:34 – A14 Low-temperature alarm limit

31:55 – A27 DI1 delay and A28 DI2 delay

32:17 – A37 Condenser high alarm limit

32:41 – A54 Condenser high block limit

33:45 – A72 Voltage protection enable

34:03 – A73 Minimum cut-in voltage and A74 Minimum cut-out voltage

35:04 – A75 Maximum Voltage

37:37 – d-- Defrost

37:49 – d01 Defrost method

38:32 – d02 Defrost stop temperature

38:50 – d10 Defrost stop sensor

40:51 – d03 Defrost interval

41:16 – d04 Max defrost time

43:38 – d05 Defrost delay at power up (or DI signal)

44:29 – d06 Drip delay

44:49 – d07 Fan delay after defrost

45:49 – d08 Fan start temperature after defrost

47:21 – d09 Fan during defrost

47:40 – d10 Defrost stop sensor (part II)

48:16 – d18 Compressor accumulated runtime to start defrost

50:04 – d19 Defrost on demand

53:26 – d30 Defrost delay after pull-down

53:53 – F-- Fan control

54:03 – F01 Fan at compressor cutout

55:00 – F04 Fan stop evaporator temperature

55:51 – F07 Fan ON cycle and F08 Fan OFF cycle

56:28 – c-- Compressor

56:37 – c01 Compressor minimum ON time

56:47 – c02 Compressor minimum OFF time

57:01 – c04 Compressor OFF delay at door open

57:51 – c70 Zero crossing selection

58:22 – o-- Others

58:37 – o01 Delay of outputs at startup

59:11 – o02 DI1 configuration

1:01:36 – o05 Password

1:02:08 – o06 Sensor type selection

1:02:27 – 015 Display resolution

1:03:31 – o23 Relay 1 counter, o24 Relay 2 counter, and 025 o24 Relay 3 counter

1:04:13 – o37 DI2 configuration

1:04:52 – o61 DI2 configuration

1:05:07 – o67 Save settings as factory

1:05:39 – o71 DO2 config

1:06:23 – o91 Display at defrost

1:07:04 – P-- Polarity

1:07:06 – P73 DI1 input polarity and P74 DI2 input polarity

1:07:32 – P75 Invert alarm relay

1:07:59 – P76 Keyboard lock enable

1:08:21 – u-- Readouts

1:08:30 – u00 Controller Status

1:09:37 – u01 Air temperature (Sair)

1:10:12 – u58 Compressor relay status, u59 Fan relay status, u60 Defrost relay status, and u63 Light relay status

Find out more about the Danfoss ERC 213 HERE.

Learn more about Refrigeration Technologies at refrigtech.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #11 - Superheat, The True Meaning Jun 25, 2018

In this podcast, we discuss the real significance of superheat and why it is much more than "a way to set the refrigerant charge on a fixed metering device."

Superheat is the temperature of a vapor above saturation. Many people use it to set the charge on a piston or fixed orifice, but that's not its only purpose. Superheat is a much more important reading than that, and you can take that measurement at a few different places. For example, most of us measure it outside. However, to determine how the system is feeding the evaporator coil, we would take superheat at the evaporator outlet (6-14 degrees is normal for a TXV). However, superheat matters regardless of the metering device type.

Zero superheat indicates that the refrigerant is still at saturation; it is in a mixed state, not entirely vapor. So, we know that we are "overfeeding" the evaporator coil. The boiling process does not finish in the evaporator; it continues into the suction line. Overfeeding is a problem because our evaporator might not boil off all the refrigerant, and we could send liquid to the compressor. The system may be overcharged, or the evaporator load may be too low.

Excessive superheat indicates that the refrigerant is boiling off too quickly in the evaporator coil. In those cases, we are starving or underfeeding the evaporator coil. The boiling process ends too early in the evaporator coil. The system may be undercharged or have too much load on the evaporator coil.

When our superheat is within the proper range, we are feeding the evaporator coil correctly. The majority of that evaporator coil is being fed with boiling refrigerant.

Learn more about Refrigeration Technologies at refrigtech.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Go From Tradesman to Franchise Empire Jun 21, 2018

This is the story of WITH JOSHUA NICHOLLS FROM PLATINUM ELECTRICIANS and how he went from pulling wire, to creating a franchise empire to giving back.

PCO Air Purification with Jon Bennert Jun 19, 2018

In today's podcast, Jon Bennert with Air Oasis talks about photo-catalytic oxidation (PCO) air purification. He explains how it works and what it does.

The NANO products are PCO-type technologies. These technologies were initially developed for NASA storage systems on the International Space Station. Photo-catalytic oxidation (PCO) products work to reduce or sterilize pollutants or organisms in the air by using light. Sunlight produces UV rays that can kill nasty germs in the air; PCO products work similarly and may have UV lamps or not. (NANO units use UV lighting.)

The UV isn't all that effective by itself. However, UV light can produce pollutant-fighting ions when the UV hits the coating within the air purifier. These ions are typically hydroxyl ions, which are more effective than ozone but don't last very long. So, PCO products are most effective when they have a large surface area with the catalyst.

You can get all sorts of bacteria, yeast, and fungi inside a home. Humidity will usually only make those worse. Not to mention, you also have VOCs from cleaners and building materials, which may smell nice but greatly reduce your air quality. Humans also create plenty of pollution through humidity and dead skin cells. Air purifiers can help you deal with all of these air quality reducers. The NANO is unique, as it can run only when the fan is on and reduce ozone byproducts in your ductwork.

Bryan and Jon also cover:

UV lighting in the ductwork
Simple organisms vs. complex organisms and defense mechanisms
Ozone and ozone-generating equipment
PCO byproducts and efforts to reduce those
NANO sizing
How Air Oasis tests the product's cycles
NANO vs. competitors
Improvements to the NANO over time
How techs can recommend and sell IAQ products more effectively
Air quality testing

Find out more about Air Oasis at airoasis.com.

Check out Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #10 - Air Has Weight and Takes up Space Jun 15, 2018

In this episode, we talk about air as a form of matter. We cover air volume, density, weight, and mass and why it matters to you.

So, air has weight and takes up space. When we measure air, we typically measure it by volume (CFM or cubic feet per minute). When we say that air takes up space, we are referring to air volume. A cubic foot of air is equivalent to a 1'x1'x1' box of air. When we measure CFM, we measure how many boxes of air we move per minute. We usually want around 400 CFM per ton, though the exact number varies by system, function, and ambient conditions. Lower CFM per ton is better for moisture (latent heat) removal, while higher CFM per ton is better for sensible heat removal.

Air also has weight. When we are at higher altitudes, the air is thinner and less dense. Therefore, the air has less weight. Standard air weighs about 0.75 pounds per cubic foot (box of air). If you multiply the 400 CFM per ton standard by the standard air weight, you get 30 pounds of air per minute. That pounds-per-minute value is what we call the mass flow rate. The air density affects mass flow rate; temperature and relative humidity can change the density of air. So, the volume is the box, but density (which affects mass) is what's in the box.

Even though our goal is to move pounds of refrigerant (mass), we care about CFM (volume) because fans move air regardless of density. The blower affects the CFM, but the mass flow rate is more important to the coil. We have to adjust our volume flow rate to achieve a proper mass flow rate.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Special EP Inverter Equipment With Ralph Wolf Jun 12, 2018

In today's podcast episode, Ralph Wolf comes on and discusses inverter equipment. He also talks about Mitsubishi, Bosch, and what he’s been up to nowadays.

An inverter system can vary its output of rated capacity. Inverter equipment makes load matching much easier and is generally comfortable. These systems maintain temperatures in tighter ranges and remove more moisture with longer runtimes.

Mitsubishi is one of our top ductless systems at Kalos. Due to building codes, they are one of the only systems we can use in sunrooms and lanais. However, the building codes technically allow those systems to be used for dehumidification. Mitsubishi mini-splits can perform below average if they aren't sized correctly (even if they appear to be correctly sized).

Bosch is another manufacturer that makes inverter-driven equipment. Like Mitsubishi, Bosch is based in Asia but has been making massive strides in the American market. They use the same Y and O calls you'd see on typical heat pumps. Bosch equipment can ramp its compressor up and down to accommodate the load. You can also use a larger unit on a smaller air handler. You can also choose from a variety of coil temperatures and adjust the fan to reach your desired dehumidification. However, inverter board issues are quite common right now. We should expect some of these issues to clear up with future versions of the equipment.

Breakdowns are normal for new technologies, but Bosch has gone above and beyond to fix issues by bringing their engineers to the USA to analyze our faulty equipment. The future is bright for Bosch and inverter technology.

Bryan and Ralph also discuss:

Choosing new inverter equipment
Improper compressor operation
Compressor sizing effects on operation
ECOER systems
Inverter technology and controls
Short cycling prevention
Heat dissipation issues in capacitors
Ductwork for inverter equipment

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Basic Refrigerant Circuit Revisited (Part 2) Jun 07, 2018

Part 2 - Bert (Kalos Tech) and Keiran (Kalos Apprentice) join Bryan in the studio to talk through the basic refrigerant circuit and how it functions. They talk compressor, condenser, metering device, and evaporator as well as the four lines and the states of the refrigerant as it travels.

The four lines that move refrigerant are the suction line, discharge line, liquid line, and expansion line. The suction line moves cool superheated vapor from the evaporator to the compressor. Then, the discharge line moves very hot superheated vapor from the compressor to the condenser. The liquid line runs warm subcooled liquid from the condenser to the metering device. Of the four lines, the expansion line is a bit controversial, as it doesn't even exist in some systems. It runs from the metering device to the evaporator and expands the liquid refrigerant so that some of it can flash at the evaporator inlet. You may see an expansion line on mini-splits, but many typical residential split systems will lack an expansion line.

The suction line draws vapor to the high side of the system, and the discharge line discharges high-pressure vapor to the condenser. A liquid line gets its name from the fact that it carries liquid to the metering device. The expansion line gets its name because it expands the liquid/vapor mixture (reducing pressure, continuing the metering device's job).

We also discuss:

Evaporation vs. boiling
Condensing temperature over ambient (CTOA)
Superheat and subcooling
Line dryers
Saturation
Feeding evaporator coils
Where to measure superheat

Basic Refrigerant Circuit Revisited (Part 1) Jun 05, 2018

Part 1 -Bert (Kalos tech) and Keiran (Kalos apprentice) join Bryan in the studio to talk through the basic refrigerant circuit and how it functions. They talk compressor, condenser, metering device, and evaporator as well as the four lines and the states of the refrigerant as it travels

They talk about the compressor, condenser, metering device, and evaporator as well as the four lines and the states of the refrigerant as it travels. We have already covered all of the basic components in earlier podcasts, which you can check out HERE; we focus more on accessories, refrigerant movement through the circuit, and scientific concepts in this episode.

We also discuss:

Pumps vs. compressors
Refrigerant and air-cooled compressors
Flooding a compressor with liquid refrigerant
Crankcase heaters
Temperature vs. heat vs. BTUs
VRF vs. ductless

Making of a TV Show About Home Performance May 31, 2018

In today's podcast, I talk with Corbett Lunsford about his new show about home performance and diagnosis. Home Diagnosis airs on PBS in winter 2018. Even though Home Diagnosis mostly deals with building performance, HVAC work is a large component of overall home performance.

Corbett Lunsford used to be a pianist before becoming a building performance expert. He was already familiar with media and decided to launch a YouTube channel. The goal of the YouTube channel was to bring visual information and practices to the masses. Since then, he has been working to create a much larger mass media project to let HVAC professionals and consumers know about building performance. Home Diagnosis is Corbett's means of bringing awareness to whole-home performance as buildings become much tighter.

The main goal of Corbett's TV show is to put home performance on the same level of awareness as car performance and athletic performance. Many factors contribute to comfort, but it is not all the responsibility of the HVAC technician. The home performance field addresses ductwork and the overall design of the house to provide the most accurate and holistic comfort solutions. The TV show also empowers consumers to talk to experts to help them achieve their comfort targets, not just request a certain repair.

While HVAC technicians make up for losses in a building enclosure, building science assesses the issues with the enclosure.

Bryan and Corbett also discuss:

Contractor mistakes
Good and bad practices for fixing ducts
"Seeding" your clients and building trust
Giving customers options to choose other contractors
Sponsorship offers and participation
Humid Climate Conference

Learn more about Home Diagnosis HERE.

Check out Corbett's Home Performance YouTube channel HERE.

Check out Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Sealing Ducts From the Inside w/ Sean Harris May 29, 2018

Sean Harris with Positive Energy and Aeroseal Austin sat down with me at the humid climate conference and talked about how to seal ducts from the inside with Aeroseal. We regularly see air leakage by poor connections, especially when we deal with flex ducts.

When a house comes under negative pressure, it draws a bunch of air in from the outdoors or unconditioned spaces. Unfortunately, that air can be very low-quality in humid climates. The humid air can be even worse if it comes from an unconditioned space where you have leaky supply ducts. So, we can prevent that nasty attic air from coming in if we seal ducts from the inside out.

Aeroseal goes inside the ducts and is a good sealant that can be compared to Fix-A-Flat for a car tire. When pressurized air leaks from the duct, Aeroseal makes its way to the leak and expands over it. Aeroseal doesn't coat the ductwork; it merely travels to leaks and seals them up. Aeroseal looks like a mist and can seep out of leaks. So, as an extra measure of caution, be prepared to protect a customer's belongings in an attic or crawlspace.

However, sealing ducts requires a holistic approach. We need to perform quite a few tests to get an idea of the building envelope and duct design before we consider ways to seal or replace the ductwork. Sean enjoys paying attention to duct sizing and understands that sealing ducts could make a customer's comfort issues even worse in an oversized duct system.

So, Aeroseal is a great product for leaky ducts of a good size. Aeroseal is a long-lasting solution for duct leaks, but it is not a magical fix-all product.

Learn more about Aeroseal HERE.

Check out Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #9 - Commercial Maintenance May 24, 2018

Today's short episode covers five things residential techs need to consider when tasked with doing maintenance on a commercial system. We mostly talk about light commercial package unit maintenance in this episode.

If you come across fresh air filters, be sure to wash those. Some commercial units have economizers that bring in fresh air, but not all fresh air is high-quality. Wash those filters to avoid pollen and other types of outdoor gunk buildup.

Then, you'll want to check and adjust belt tension. Make sure you adjust the belt in each direction correctly; don't get them too tight. Otherwise, you might break or stretch the belt. You may also wear out the bearings or cause higher amperage on the blower motor. In general, you want the belt to be tight enough not to slip off and no tighter. We recommend using the Browning belt tension tool. You may also consider replacing the belt if need be.

You'll also want to align pulleys. Don't just align the edges; align the entire pulley. If you're dealing with sheaves, you can adjust those to tweak your CFM rate. Make sure the motor mounts are square, too.

The next maintenance step is familiar with residential techs: properly wash the condenser coils. However, you may have to "split" the coils; you'll pull them apart and put them on a piece of wood as you separate them. Even though it sounds difficult and time-consuming, splitting the coils is the only way to do a thorough cleaning.

Lastly, you'll want to check the phase balance on three-phase equipment. Phase imbalance can lead to the death of a motor; more than 2% of imbalance can cause issues, and 4% indicates a severe problem.

Check out Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Air Filters, They are More Complex Than You Knew w/ Lee Andrews May 21, 2018

In today's podcast episode, Lee Andrews with Andrews Filters talks about the complicated and important topic of air filters and filtration. He also explains why they should matter to you and your customers. As indoor air quality (IAQ) becomes more important in HVAC work, air filters will become even more important than they already are.

We classify air filters by MERV ratings. MERV ratings describe the ability of filters to capture finer particles; a MERV 11 filter will catch a lot more particles than a MERV 6 filter. Most air particulates are an average of 0.4 microns large, but most air filters only catch 5-15% of those particulates. The filter industry aims to catch smaller and smaller particulates to improve indoor air quality, protect equipment, and keep consumers healthier.

However, MERV is not a comprehensive value for efficiency. The actual filter media is also important for a filter's efficiency. Higher-quality, finer fibers will have a higher probability of catching smaller particulates. Having a greater surface area (more pleats) also increases performance. The media has a small charge, which helps a filter collect particles. Humidity, particulate insulation (dirtiness), and alcoholic pollutants (such as diesel) can discharge a filter and reduce efficiency.

Many people use MERV 8 filters, but very few understand the difference between MERV 8 and MERV 8A filters. The addendum of the MERV test (A) uses an alcohol-type product to remove the charge. So, MERV-tested filters without the addendum test can actually perform at a lower-rated level. For example, a MERV 8 filter could perform more like a MERV 5-6 filter.

Bryan and Lee also discuss:

Electrostatic charge and airflow
MERV 8 vs. MERV 8A
Loading and unloading
Board materials
Filter design and sizing
Talking to customers about filters
Energy savings

Check out Andrews Filter's website at andrewsfilter.com.

Check out Refrigeration Technologies' chemical products HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Repair Aluminum Leaks May 15, 2018

Have you ever struggled to repair a leak in an all-aluminum coil? Lance Robinson with SolderWeld talks about his product to do just that and makes a convincing case for aluminum repair.

We've been using aluminum for several decades before the shift to copper; unlike copper, aluminum is corrosion-resistant. However, copper is typically better for brazing due to its heat transfer properties and ductility. If we can get to a point where we can use aluminum for the same uses as copper, we will probably see a shift to aluminum due to its durability.

SolderWeld has recently made an aluminum repair product. Alloy-Sol is a solder, meaning that it works below 840 degrees Fahrenheit, and it gives techs plenty of time to work without worrying about melting the aluminum. Alloy-Sol works with a powdered flux, which goes on in a white paste that bonds to the aluminum and cleans it. When the flux turns clear, you can begin applying the solder to join the surfaces. You can melt the rod into your repair so long as you have that bond. You can use Alloy-Sol to perform COMPLETE aluminum repairs, not just temporary repairs.

When applying heat, make sure you apply heat perpendicularly to the repair. Repairing aluminum requires perhaps a bit more focus and finesse than copper brazing, but it is still a relatively easy process. We may not have considered aluminum repairs in the past, but they are worthwhile with the correct solder products.

Bryan and Lance also discuss:

Aluminum's low melting point
Torch usage and heat application
Working with microchannel coils
Training techs to repair aluminum
Cleaning aluminum
Fittings for aluminum piping
Aluminum repair limitations
Alloy-Sol in the auto body industry
SolderWeld's history

Learn more about SolderWeld HERE and Alloy-Sol HERE.

Check out Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #8 - Resistance Up, Amps Down May 14, 2018

This short podcast episode covers the most misunderstood portion of Ohm's law explained masterfully from 1921: when resistance goes up, amps go down.

The American Electrician's Handbook (1921) contains a lot of electrical knowledge that holds up in the present day. (The electrical testing methods don't hold up quite as well, though...) One of those principles that hold up is the idea that amps go down as resistance goes up. Amps refer to current (electrons). The ohm is the unit of electrical resistance, and it is NOT the same as mechanical resistance, such as in a compressor with locked-up bearings.

The common "water" analogy for electricity works quite well for helping us see how voltage enters the equation. Electromotive force (EMF) is comparable to water pressure, which pushes water in a hydraulic piping system. So, you can compare voltage to PSI. The current (amps, I) is comparable to the flow of water. So, if you have more pressure inside a hydraulic system, more water will flow out; as voltage (V) increases, amperage also increases. That analogy also explains why you can have volts without amps; there can be plenty of water pressure behind a closed valve, but there will be no flow.

Additionally, a smaller pipe has more resistance than a large one. So, less water (amps, I) will flow through a pipe with greater resistance (ohms, R). When resistance goes up, amps go down; the water analogy illustrates that principle very clearly in terms that we are familiar with.

With all these in mind, you can yield the three following equations that make up Ohm's law:

I = V/R

V = I x R

R = V/I

Learn more about Refrigeration Technologies chemical products HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Universal Digital Refrigeration Controls and the Danfoss ERC 213 May 10, 2018

In today's podcast episode, Jamie Kitchen talks about refrigeration controls and applications. He also tells us about the Danfoss ERC 213 universal digital controller.

Electronic refrigeration controls tend to have greater accuracy and flexibility than traditional electromechanical controls. These electronic controls also allow you to perform many more tasks than traditional ones. Electromechanical controls also wear out and lose their accuracy over time.

When you deal with applications that require various temperature, humidity, and defrost requirements, you can use electronic controls to choose between several options for the defrost method, defrost stop temperature, fan delay after defrost, etc. You can also put voltage and head pressure protection measures in place. You can optimize defrost and box temperature with electronic controls, but you can't control evaporator coil feeding. However, EEVs work well with these refrigeration controls and can adjust evaporator coil feeding. The ERC 213 has temperature and defrost sensors, but you can also configure it to work with other sensors, if you prefer.

The ERC 213 has seven different application settings (0-6). In cases where a preset option will suffice, choose between Apps 1-5. (Consult Resources for the ERC 213 installation guide, which explains each application.) However, you shouldn't assume that the electronic controls will have the same settings as mechanical controls. If you want to learn the full functionality of the ERC 213, you can use Apps 0 & 6 to customize parameters. Just remember to supply the correct voltage to the controller (120v).

Bryan and Jamie also discuss:

Customizable settings
Superheat controllers and EEVs
How defrost requirements change seasonally
Controlling compressors
Ice machines and restaurant refrigeration equipment

Resources

Find out more at Danfoss.com, and check out the ERC 213 installation guide to learn more about the ERC 213.

Check our Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Manifolds vs. Probes Battle w/ Adolfo Wurts May 08, 2018

In this episode, Adolfo Wurts from Arbiter comes on and debates why a tech would want to use a manifold over wireless probes and vice versa.

In our industry, we are likely to see a trend of moving towards wireless equipment that connects to a single device. Wireless connections and digital displays may save us money on tools and allow us to store and interpret data more efficiently. However, a manifold can help you recover refrigerant, whereas probes cannot. Manifolds also have sight glasses, which help you check for overfeeding; probes do not offer you much help on that front. Manifolds can also fit into tight spaces a bit more easily than probes, but probes have already come a long way and will continue to get better.

Manifolds may feel heavier and seem more durable, but wireless probes are actually light yet hardy, and you don't have to worry about cracking screens. Probes and manifolds are probably similarly hardy, but probes are lighter and have fewer components to damage. Probes also have a massive edge over manifolds in the area of contamination prevention.

Using your phone with probes has its advantages and disadvantages. Unfortunately, you expose your phone to situations that may damage it. However, you can access all of your readings in real-time from the phone. Your phone also has more processing power, and some apps can perform advanced calculations. You can avoid exposing your personal phone to field damage by using an older, cheaper phone just for field usage.

So, as our society and industry become more tech-savvy, probes will continue to improve. Probes that have an edge now will still improve, and you may want to consider using probes over manifolds. However, you may want to have additional hoses and a sight glass.

Adolfo and Bryan also discuss:

UEI Hub kits
Tool misuse and damage through improper storage
Software in HVAC/R apps
K-type thermocouples
Using probes in ductwork
Dehumidification

Find out more about the UEI hub kits HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

HVAC/R Conductor, Breaker, and Fuse Selection May 07, 2018

In this podcast episode, Phil Barr joins Bryan to explain sizing for wires and breakers in HVAC/R work. You will be able to select breakers, conductors, and fuses properly and without confusion. Phil Barr is the leader of the electrical division at our business.

HVAC/R equipment may have hermetically sealed motors. Unlike squirrel-cage motors, hermetically sealed motors have an outer shell that makes it impossible to access the inner components. Semi-hermetic equipment, such as some compressors, look like hermetic equipment but can open up. Wire sizing varies between hermetically and non-hermetically sealed motors, and the NEC explains the wire sizing requirements, but YOU need to know the context for those requirements.

Once you know your equipment type, check the nameplate with a rating, such as MCA, RLC, branch circuit selection, etc. The manufacturer will establish that rating, and you will use it to look up the correct wire sizing requirements. Wire insulation and conductor type also dictate the sizing and installation requirements. Conductor length and voltage drop also affect wire sizing.

Fuses or circuit breakers prevent shorts. Shorts are undesigned paths with little to no resistance, so fuses and circuit breakers protect equipment and buildings from overcurrent due to shorts, NOT thermal overload. So, you use MOCP as a guideline for sizing your breakers. Thermal overload protection keeps conductors from melting under overload conditions.

If you want a breaker that is under the MOCP value but it exceeds the MCA and the terminations are rated correctly, you can typically use a breaker between the MCA and MOCP. However, you will still want to follow manufacturer recommendations and check with your AHJ.

Phil and Bryan also discuss:

MCA (minimum circuit ampacity)
"Undersized" conductors in new constructions
Reducing voltage drop
MOCP and related terms
Inrush current
Adjustment factors

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Humidity Talk w/ Johnathan Jones May 01, 2018

In today's podcast episode, Johnathan Jones from Clean Comfort, Ultra-Aire, and Therma-Stor talks to us about humidity, dehumidification, and ventilation.

Relative humidity (RH) is a moisture content ratio that depends on temperature. Hotter air can hold more moisture, and colder air can contain less moisture. You can increase or decrease the temperature to change the relative humidity, but the dew point stays the same. The safest humidity range is between 40-60%. It is typically harder to add humidity to an arid place than to remove humidity from a tropical place.

We work to control the dew point (keeping it below 55 degrees). When we keep our indoor temperatures well above the dew point, we don't have to deal with condensation and moisture, which leads to microbial growth. We encounter two conflicting schools of thought: reduce the fan speed to control humidity or raise the fan speed to keep the ducts warm enough to prevent "growth." However, a dedicated dehumidifier takes care of the space without requiring fan speed changes.

A lot of indoor moisture comes from our bodies, such as by breathing and talking. Local ventilation, especially during cooking and showering, helps reduce moisture ONLY if it sucks in quality outdoor air. Ventilation strategies can be balanced or imbalanced. Balanced ventilation helps us avoid negative ventilation; mechanical ventilation brings the building under positive pressure. When a building is under positive pressure, air gets pushed out to maintain balance. Additionally, pollutants tend to stay out. However, positive pressure can cause condensation to occur in colder climates and works best alongside a dehumidifier.

We also discuss:

Moisture units (pints, pounds, grains)
Infiltration
Encapsulated attics
ERVs in coastal states
Ventilating dehumidifier setup
Comfort differences based on humidity alone
Latent and sensible capacity
Hot gas reheat applications
Dehumidifiers and energy efficiency

Check out Clean Comfort HERE, and check out Therma-Stor HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out Refrigeration Technologies HERE.

Short #7 - A Moisture Problem Apr 27, 2018

In this short episode, we replace a dirty "M" word (mold) with another "M" word (moisture) that gets to the root of the problem.

"Mold" and "mildew" can freak out your customers. For years, I've refrained from saying "mold" at my own company and trained my techs to avoid it AND "mildew." Instead, we have called it "biological growth" or "organic growth." Those still aren't great. Just recently, my friend Joe Medosh suggested referring to fungal growth as a "moisture problem" instead.

"Moisture problem" is a fact-based and less disgusting term. We can focus on solutions with indoor air quality (IAQ) to address the overarching issue that causes the growth, not just the nasty growth.

In some cases, parts of the home may hit the dew point in colder temperatures. So, drywall is particularly vulnerable to falling to dew point if the building envelope has been poorly sealed. So, we have a practical means of reducing relative humidity below 55%. We can also seal the envelope better and address potential issues related to infiltration.

A duct with poor or compressed insulation may also be prone to "moisture problems." We can address those "moisture problems" by properly strapping the duct. In cases when air handlers sweat by an improperly sealed duct, we seal the duct correctly to nip the problem in the bud. In the case of sweating vents, we must analyze the supply air, check the blower fan speed, and look for restrictions. Make sure all components are clean and that you seal up any leaky areas.

Remember, "moisture problems" do NOT occur because hot meets cold! The moisture content and dew point are the key factors, not just a temperature differential.

If you have an iPhone subscribe to the podcast HERE and if you have an Android phone subscribe HERE.

Prevent Compressor Murder Part 2 w/ Emerson Apr 24, 2018

Here is part 2 of the discussion with Trevor Matthews about the causes and prevention of air conditioning and refrigeration compressor failure.

Slugging occurs when the compressor attempts to compress oil or liquid refrigerant. A telltale sign of slugging is valve plate damage. On a semi-hermetic compressor, you can remove the screws on the head to access the valve plate. Wrist pin wear occurs during slugging the wrist pin is between the rod and the piston; you should test the wrist pin to see if it makes a knocking sound before you dismiss all other possibilities and replace the valve plate.

Overheating occurs when there is a system-related issue. Compression ratio is an indicator of overheating, but few technicians check it often enough. A requirement for external cooling and dirty condenser coils can cause overheating. Overheating also causes oil issues; when a compressor gets too hot, oil breaks down and loses its ability to lubricate the bearings.

Oil loss is a tricky cause for failure; it is hard to notice without a sight glass. Short-cycling can lead to oil loss over time, and bearings will begin to wear when there isn't enough oil to lubricate them.

Contamination usually occurs when moisture corrodes the copper plating and introduces acid to the system. Acid and sludge are the most common contaminants. Proper reaming practices also keep copper out of the system and reduce the risk of acid contamination.

Trevor also discusses:

Slugging in scroll compressors
Sight glasses and oil measurement
System load and suction pressure
Maintaining design compression ratio
"Blow by"
Oil separators
Replacing line dryers
Components to troubleshoot and inspect

Verifying System Operation Sheet from Emerson http://hvacrschool.com/Emerson

Verify Diagnosing Compressor Failures from Emerson http://hvacrschool.com/CompFailures

Short #6 - Energy? Compared to What? EP1 Apr 20, 2018

In this short podcast, we start the conversation about "Energy? Compared to What?" and explore several energy comparison examples.

When we think about energy, we can confuse some terms. For example, temperature and heat are related but NOT synonymous. Temperature is an average measurement of heat energy; when many molecules move at a bunch of different speeds, the temperature represents the average speed of those molecules. Temperature does NOT measure total heat content. Voltage and amperage are two more confusing terms, and they get even harder to understand and differentiate when you throw "power" around.

In most diagnostic cases, we usually measure things to compare them, such as using a voltmeter to measure a difference in electrical charges. We could compare the usage of a voltmeter to a temperature difference between two rooms. The wall between the rooms presents resistance between the temperatures of the two rooms (R-value, which affects energy transfer), and the voltage is analogous to the potential difference between the rooms.

In the HVAC industry, we can witness energy differentials in temperature, charges, and pressure. Resistance gets in the way of these differentials reaching equilibrium and must be accounted for in our readings. Resistance affects the rate of energy transfer; that resistance can show up as friction, R-value, and other values that affect the total amount of energy transferred.

Many techs also go wrong when they assume that a 120V blower motor draws twice as many amps as a 240V blower motor. In truth, the 240V blower requires twice as many amps to hit the same work target. In a 240V motor at 120V, it would draw far less amperage and result in less than half the usual horsepower.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Prevent Compressor Murder Part 1 w/ Emerson Apr 17, 2018

In today's podcast, we talk with Trevor Matthews with Emerson. He tells us about the causes and prevention of air conditioning and refrigeration compressor failure.

Most compressors don't die a natural death... they're murdered. Of course, that's to say that installation and maintenance play a major role in the compressor's operation and lifespan. Electrical and mechanical failures are the two broad causes of compressor failure.

When it comes to electrical failures, Trevor often sees single-phase compressors fail early when their electrical components don't receive proper inspections and care. For example, contactors may go too long without inspection or replacement. Three-phase compressors are also prone to phasing issues and may run backward.

Common mechanical failures deal with oil in the system. Oil lubricates the bearings inside the compressor. Unfortunately, that oil can mix with liquid refrigerant, become diluted, or experience acid contamination. Some oil-related failures include floodback, flooded starts, slugging, overheating, oil loss, and contamination. Compressors cannot compress liquids, so many of them fail when the refrigerant condenses to a liquid inside the compressor.

Many failures occur because technicians don't think they have enough time to troubleshoot or inspect the whole system. Trevor recommends setting up a checklist with all of the tests you need to perform.

Trevor also discusses:

Service replacement compressors vs. OEM compressors
Megohmmeter usage
Causes of floodback/flooded starts
Compressor superheat
Suction accumulators
Bearing wear
Temperature control and pump cycles for controlling flooded starts

Verifying System Operation Sheet from Emerson http://hvacrschool.com/CompFailures

Intro to Manual J & S w/ Jack Rise Apr 12, 2018

In today's podcast episode, we talk with system and duct design educator Jack Rise about ACCA Manual J load calculation and Manual S system selection.

Many people know about Manual J, but relatively few techs follow it properly. When people attempt to do Manual J calculations, many of them go wrong when they overestimate the difficulty of the equations in Manual J. However, many of these techs do better when they can use software like Wrightsoft to help with their load calculations. The best way to approach load calculations is to develop confidence in software programs and field experience (sizing equipment and sealing ductwork); you are more likely to make mistakes if you put all of your confidence in one or the other. Some techs also don't take the time to measure buildings properly if they are either over-reliant on technology or too confident in their field skills.

Manual S is all about equipment selection after the load calculation. However, much of the manual is not useful for fieldwork. The rules are also not as regionally thoughtful as they could be, especially regarding furnace sizing and the consequential heat loss. Manual S is only useful if you perform a Manual J calculation first and use that result as a guide. Rise does not believe that Manual S is bad, but he thinks it gives installers way too much leeway on sizing as it stands.

Jack and Bryan also discuss:

Wrightsoft
Manual J practices in different types of buildings
Envelope leakage in retrofit applications
Most important chapters of Manual S
Accounting for sensible and latent heat load
New ventilation requirements
Odors, cooking, and building design
Increasing airtightness in building construction
Encapsulated attics

Learn more about ACCA standards and codes at acca.org.

Learn more about Wrightsoft HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Low Voltage Diagnosis Basics w/ Bill Johnson Apr 03, 2018

In this podcast, Bill Johnson shares his practical tips to make low-voltage electrical diagnosis easier in HVAC work. Bill is one of the original authors of the Refrigeration and Air Conditioning Technology manual.

A common issue that techs have in low-voltage diagnosis is that they overcomplicate the issue. Techs should take the time to trace out the system and see where all the wires lead. The techs can be more effective if they know a system's components and those parts' relationships. During diagnosis, some techs also don't allow themselves to use their hands. Bill recommends using an alligator clip on the system as you "walk your way" through the whole circuit for diagnosis.

"Short" is a commonly used term. A true "short" occurs when the current takes an undesigned path with almost no resistance. Some of the things that we casually call "shorts" are actually open-circuit issues where the current doesn't make it all the way through the circuit. Real "shorts" include shunts on the load and blown fuses. If a fuse blows but everything else in the low-voltage circuit seems to be operating fine, check the amperage at the transformer outlet.

Electronic boards give techs a lot of trouble because they seem complicated. But, in the end, these boards are just switches where a hot wire goes in and a hot wire goes out. (The common wire goes straight through the board.) The board is nothing more than a distributor of voltage, and the best way to work on them is to simplify them. You can simplify electrical boards by figuring out the inputs, outputs, and sequence of operation.

Bill also discusses:

Grounding on one leg
Connecting to ground
"Probing" the hot side
Measuring amperage on a thermostat
"Spark-tricians"
Commercial vs. residential low-voltage electronics
Stripping wires

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Introduction to Walk-in Refrigeration Mar 28, 2018

In this podcast episode, refrigeration tech Eric Mele talks us through some common characteristics of walk-in freezers and refrigerators. Eric recently discussed reach-in refrigerators on the podcast, and you can listen to him talk about those HERE.

Common walk-in applications include coolers, freezers, and wine rooms. You may even see some package units. Condensers typically go on top of the box or the roof, and evaporators are inside the refrigerators. Many of these refrigerators also have pump down solenoids on their equipment. Thermostats mostly control the opening or closing of the solenoid valve. To cycle the unit, you shut off the liquid line and let the system pump all the refrigerant into the condenser.

Evaporators tend to come in the side-discharge or pancake-style varieties. Wine rooms may also have ducted evaporators. Some older evaporators may not have fans; we call these gravity evaporators.

Heaters are components that you'll see quite often on walk-in equipment. Drain pan and drain line heaters are critical for walk-in coolers, especially freezers. You can test them by touch or by using a thermal imaging camera. Freezers also have door heaters. Walk-ins also have low-ambient controls. Fan cycling is a low-ambient strategy, but commercial walk-in refrigerators may also have a headmaster.

When you first start working on walk-ins, you may feel overwhelmed if you don't have all the parts on you. However, if a unit has multiple fans and only one is not working, you can typically still run the equipment if you cover the faulty fan and seal up the opening in the shroud. The goal is to get (or keep) the equipment running to save consumable products.

Eric and Bryan also discuss:

Pressure switches
Defrost controls
Troubleshooting equipment (sight glasses, etc.)
Adjusting charge
Superheat values
Patching coils

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #5 - Wire Routing & Connection Mar 27, 2018

In this short podcast episode, Bryan covers some basic best practices for wire routing and wire connections in HVAC work.

When it comes to electrical work of any kind, the wires must have proper protection. For example, the wires must be in the proper conduits. They must also work on appliances that they are rated for. HVAC technicians must also understand their qualifications against local codes to ensure they have been authorized for electrical work.

You also NEVER want to route the wire through an opening you can't shove your finger through. If you can cut your finger on an opening, then that opening will probably cut the wire. If you need to run a wire through one of those difficult places, use a grommet. In any case, make sure you properly strap the wire, such as with zip ties. Do NOT trim wires to make them fit a connection.

When routing wire, you WILL be making connections inside the appliance. Make sure you know your connectors and their ratings to make the best, safest connections possible. Check if there is any tension at the connections and disconnects; if there is tension AGAINST the terminal, check your wire angles and adjust them until they sit still or have a little tension towards the terminal. The goal of creating a good connection is to avoid melting, arcing, and other unsafe conditions. Replace melted plugs and leads entirely if you come across them.

When you make a crimp connection, make sure you give them a good tug to check their tightness. Make sure there are no exposed wires by your crimp connections. Soldered connections are usually excellent connections, especially with heat shrink over them.

Bryan also discusses:

Using torque screwdrivers
Terminal crimping (insulated terminals, indentations, using ratcheting crimpers)
Lineman splice
"Doubling over"

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Furnace Commissioning Part 2 w/ Jim Bergmann Mar 21, 2018

In the second part of this podcast series, Jim covers the basics of furnace commissioning in more detail with some common-sense practices. (Listen to Part 1 HERE.) Even though installers set up a furnace system, the technicians help with the equipment startup and commissioning. That way, two parties can ensure that the installation is proper.

The technician is perhaps better equipped to check the electrical connections. As technicians, we can also check the polarity of the power supplies (ensuring that the sine waves are in sync). If the polarity is backward, sometimes the hot wire has been switched with another wire, or you may have to switch the primary or secondary on the transformer. Flame rectification also ties directly into the electric components of a furnace.

Inspection is also a critical component of furnace commissioning. As such, our eyes and ears will be our most important tools during the commissioning process. During the inspection, we should check over the original factory parts to ensure that everything is in order and that the furnace will operate safely.

After we've calculated the temperature rise and set the blower speed, we must evaluate our static pressures. The static pressures let us know how our motors and ductwork are doing. The goal is to get our static pressures as close to 0.5" wc as possible.

Be sure to perform a flame disruption test to ensure that the flame does not starve. Many technicians also fail to check the high limit cutout. When techs fail to check that cutout, the heat exchangers can break from stress. To check that high limit cutout, we can use a piece of cardboard to block the filter; that blockage raises the temperature, and it's our job to make sure that the limit cuts out and shuts the burners down.

Jim also discusses:

Grounding screws
ECM motors
Home insulation and furnace/ductwork sizing
Furnace switches/safeties
Flame rod microamps

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #4 - Blower Taps Mar 19, 2018

In this short podcast episode, Bryan talks about blower taps in furnace systems. He explains how to set up their fan speeds and repair them.

Before you even look at the blower taps in a system, you must know a bit about the system design. Is the system supposed to remove high amounts of sensible heat? What is the capacity? How quickly should the thermostat drop? When a system is supposed to move lots of heat and has a high capacity, it needs high airflow; to run optimally, the system needs higher fan speeds to move more CFM per BTU. Moreover, a Manual J calculation can tell you how much sensible and latent heat the system must move. Also, keep in mind that system tonnage does NOT always indicate the amount of BTUs a system is actually moving.

Conversely, to calculate the airflow needed for heating, you must look at temperature rise. Ideally, your temperature rise should be near the middle of the temperature-rise range.

So, how do you set the airflow and know how much you're producing? That's where you measure your static pressure and look at fan tables. Remember to make sure the blower is clean and to factor in additional resistance from components like heat strips or filters. Alternatively, you can measure airflow with a duct traverse or by using an airflow hood. Then, you set the fan speed accordingly.

Overall, to set the blower taps, you need to be able to measure your airflow and read fan charts. If you're merely commissioning a new system, measuring airflow becomes less important; instead, you must ensure that the manufacturer's fan charts are correct. Remember, the airflow needs to be different for a customer's heating and cooling needs.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Furnace Commissioning Part 1 w/ Jim Bergmann - Input / Rise Mar 15, 2018

In today's podcast episode, Jim Bergmann covers furnace commissioning, including setting up furnace input, clocking the meter, setting temperature rise, and much more. The goal of commissioning is to optimize a furnace's efficiency; we want to make sure we correctly engineer the intake/exhaust system to extract as much heat from the flue gas as possible.

The commissioning process for an 80% furnace is pretty similar to that of a high-efficiency furnace. Checking gas pressure, setting temperature rise, and combustion analysis are critical procedures when commissioning both furnace types. Moreover, you must know the heat content of the fuel and the amount of fuel going into the furnace before you can determine the correct input. There is an acceptable range for gas pressure, typically within 10% of the specs (usually 3.5" wc, so the acceptable range is 3.2-3.8" wc). Both the gas pressure and heat content let you know how efficiently the furnace is firing.

When checking the input, you must clock the gas meter; you do that by timing a single revolution of the gas meter and determine how much fuel goes into the appliance during that time period. You can't have the water heater on at the same time that you are clocking the meter. When you clock the meter, you can start with a gas pressure of 3.5" wc and go up to 3.8" wc. When clocking the gas meter, you may realize that the orifices are incorrectly sized.

Ideally, you want your temperature rise to be in the middle of the manufacturer-specified range. For example, if the range is 40-60 degrees, you would want your temperature rise to be close to 50 degrees).

Jim also discusses:

Weighing condensate
Primary vs. secondary air
Excess air
Changing/resizing orifices
Other gas lines in the home
Ductwork sizing for temperature rise/CFM
Filter considerations

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #3 - Saturation Mar 12, 2018

This short podcast episode is about saturation and what it means. Bryan covers related topics, including boiling, evaporation, and condensing.

Saturation refers to something that is "full" of something else. In science, "saturation" refers to a substance being in the middle of a phase change. (For example, boiling water stays at 212 degrees until it all boils off and becomes water vapor.) In HVAC, we often use the term to refer to refrigerant with liquid and vapor are present at the same time. The refrigerant is typically both liquid and vapor in the evaporator and condenser; phase changes occur in those two components as refrigerant changes from a liquid to a vapor and vice versa.

Refrigerant tanks are contained systems, so the liquid-vapor mix remains at equilibrium, and the temperature and pressure will change at a predictable rate. That is why we can use the P-T chart to determine the refrigerant type; a given type of refrigerant that is changing state at a given pressure will always be a certain pressure.

The process of changing state is where we can utilize so many more BTUs of heat. When a substance is at saturation, that substance will not increase in temperature so long as it remains in its current state. However, that substance will continue absorbing heat until it fully changes its state. We call the added heat that does NOT contribute to a temperature change "latent heat." Evaporators are so effective at absorbing BTUs of heat because refrigerants have relatively high latent heat of vaporization values; it takes a lot of added heat to make a refrigerant change from liquid to vapor.

However, evaporation can occur WITHOUT boiling. Temperature is only the average heat content, and some faster-moving liquid molecules can still break free and become gas.

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Measuring Airflow For Techs Mar 08, 2018

In this discussion with Bill Spohn from TruTechtools.com, we cover the practical steps and tools for YOU to start measuring airflow today, if not sooner.

There are several ways to measure airflow; when measuring airflow, start with the "why" rather than the "how." Understand what the goal of the airflow is before you begin taking measurements in random places.

You can take a bulk measurement at a return, but you have to be prudent to avoid human error. The best way to avoid error is to use a TrueFlow grid, which replaces the filter and uses a pitot array to measure airflow in the return. Another relatively easy way to get a bulk measurement is to use a flow hood. However, it can be easy to mess up the positioning of a flow hood (or not have enough room for it).

Many techs misuse tools like vane anemometers and collect poor data. Vane anemometers can gather information throughout the duct (mini vane) or over the supply or return (larger vane). You want to pick up the micro-transitions in air velocity to get quality data; you can use either point or traverse measurements and average those readings to come up with your average CFM.

We can take measurements INSIDE the duct with pitot tubes (although we have our reservations about using those), hot wire anemometers, and mini vane anemometers. In-duct measurements require multiple measurements and consistency during testing.

A common system airflow measurement doesn't measure CFM at all; that measurement would be static pressure. However, you need to have the correct tables and understand all of the load requirements to measure static pressure effectively.

Bill and Bryan also discuss:

Pitot tubes vs. static pressure probes
Air movement metaphors
Point vs. traverse measurements
Static pressure drop
Total system airflow setup
Ventilation airflow

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #2 - Delta T Mar 07, 2018

Today, Bryan discusses delta T (evaporator air temperature split) what it is, what it means, and how to avoid some common pitfalls.

Delta T is NOT the air temperature rise on a furnace, and it is NOT the design temperature difference (DTD). Instead, delta T refers to the temperature split between return air entering the evaporator coil and the supply air leaving the unit. Typically, 20 degrees (Fahrenheit) is a desirable split, but there is still a range based on relative humidity, enthalpy, and airflow. The range can be as high as 24 degrees.

To measure delta T properly, you need high-quality probes. (Don't use cheap dial probes if you don't want an inaccurate measurement.) Whenever you expose a probe to another probe via an air gap, they can affect each other's temperatures. Radiant heat transfer occurs between them, and you can get incorrect readings. In general, you want to keep your supply probe downstream of the coil. Do NOT use an infrared thermometer to measure the temperature split. Infrared thermometers are inaccurate and may also pick up duct gains.

Delta T is not a fixed value, but it is still rather predictable. You can use our calculator to help get an idea of the measurement you're aiming for. Some factors that reduce the temperature split include high airflow, high relative humidity, and low capacity (and all of its possible causes).

High temperature splits typically occur due to poor airflow. Dirty filters and coils are the main culprits of poor airflow and high temperature splits by extension. Dehumidification mode and lower relative humidity may also result in higher delta T values. (However, dehumidification mode is usually intentional and is rarely a cause for concern.)

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Beating the Ego, Ignorance, and Insecurity Monster w/ Andrew Greaves Mar 01, 2018

In this simultaneously heavy and lighthearted discussion, Bryan Orr and Andrew Greaves discuss ego, Dunning-Kruger, insecurity, and apprenticeship in the trades.

In the early days, apprenticeships were quite different from the way they are today. One-on-one mentorship used to be a much more significant component of early apprenticeships, but that style of training is uncommon for today's apprentices in all sorts of trades. As a result, many young technicians enter the field too quickly and don't have the training to perform a job skillfully.

As such, many inexperienced techs become confident with bare-minimum work because nobody points out their mistakes. Moreover, many green techs also don't have the self-awareness to recognize their lack of skill. We call that disconnect between confidence and skill the "Dunning-Kruger effect." Another common scenario is when techs understand that they don't know something but are too embarrassed to admit it. Unfortunately, a tech's ego can get in the way and make them stick to their guns for no good purpose.

However, old-timers are also part of the ego-ignorance equation. Many of them fail to explain the "why" behind their practices. Some old-timers share bad practices without knowing what they're doing. Moreover, when leadership breeds a culture of ignorance, the younger technicians will be set up for ignorance and ego problems.

The way to move past the Dunning-Kruger effect and check your ego is to think about what you're thinking about. Question the validity of your OWN thoughts and ideas, and accept that you could be wrong or have a flawed understanding.

Bryan and Andrew also discuss:

Techs' behavior on social media
Cognitive bias
Metacognition
Organizations that breed ignorance and ego issues

Check out AK HVAC on YouTube - https://www.youtube.com/user/akgreaves

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Short #1 - Refrigerant Circuit Basics Feb 22, 2018

In this short episode, we review the basics of the refrigerant circuit. The standard HVAC refrigeration circuit has four main components: compressor, condenser, metering device, and evaporator.

The compressor squeezes refrigerant vapor into a smaller volume by applying lots of pressure. It simultaneously moves and compresses gaseous refrigerant. The more a compressor has to compress a gas, the less gas it moves. The more gas a compressor moves, the less gas it compresses. Then, the refrigerant leaves the compressor via the discharge line. The discharge line is very hot because the temperature increases with pressure.

The hot vapor feeds into the top of the condenser. The condenser brings the gaseous refrigerant back down to a liquid. Condensers come in all shapes for various applications, but all condensers' main goal is heat exchange. Condensers desuperheat, fully condense (change vapor to liquid), and subcool. Subcooled liquid refrigerant leaves the bottom of the condenser via the liquid line.

The liquid line leads warm, subcooled liquid refrigerant to the metering device. The metering device's goal is to drop the refrigerant's pressure. That pressure drop facilitates boiling in the evaporator coil.

The evaporator absorbs heat from the space. Fans blow warm air over the coils, allowing that heat to come into contact with the refrigerant. The refrigerant boils when it absorbs enough heat. The last few rows of the evaporator are where superheating occurs. Superheat is the temperature above the saturation point; superheat indicates that the refrigerant is all vapor, no longer a liquid-vapor mix. Then, the vapor refrigerant travels back to the compressor via the suction line; the refrigerant circuit restarts. The suction line is rather cool; we use some of that cool refrigerant gas to cool down the compressor.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bi-Polar Ionization and IAQ w/ Jon Bennert Feb 21, 2018

Jon Bennert from Air Oasis teaches us about PCO and Bi-Polar air purification and how it improves indoor air quality through ionization.

Photocatalytic oxidation (PCO) is a technology field that uses catalyst metals, hydration agents, and lights to help remove pollutants from the air. These technologies shine a light source on a photocatalyst metal that reacts with pollutants in the air. These pollutants include volatile organic compounds (VOCs), viruses, mold, and other unwanted particles in the home. Some bacteria that are good for you in your gut are NOT good in your respiratory system.

Bi-polar ionization causes reactions to occur with the pollutants. Ionization could potentially break down molecules or genetic material in VOCs and viruses, respectively. Other biological contaminants, including mold and bacteria, also have their proteins broken down and become unable to replicate or reproduce. Larger particles, like dust, are forced to clump together and become so heavy that they fall out of the air.

The air motion in the Bi-Polar product line is the mixture of positive and negative ions that are splitting water vapor molecules. So, you can tell if the Bi-Polar products are working if you can feel airflow; you can tell that the product is generating ions. These ions work to break down harmful particulates in the air AND eliminate odors. Bi-Polar products that use ionization are desirable for people with allergies or homes with lots of shedding pets.

Bi-Polar products are small and easy to install. They simply fasten to the shroud with magnets. These products also come in some voltage ranges, and they have a small energy footprint as well.

Jon also discusses:

Ionization history
Petri dish tests
Bi-Polar products and PCO usage
Outdoor air standard qualifications
Servicing Bi-Polar products
Ice machine contamination

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Reach-In Refrigeration w/ Eric Mele Feb 14, 2018

In today's podcast episode, Eric Mele comes on to talk about reach-in coolers (refrigerators), freezers, and wine coolers with some mindset and technical tips. We mostly discuss self-contained equipment.

Coolers are medium-temperature applications, while freezers are low-temperature applications. Wine coolers vary from normal coolers because they have slightly higher temperatures and controlled humidity. The cooler must control humidity to preserve the wine quality and prevent the cork from swelling.

Metering devices vary with the size and type of equipment. We typically see capillary tubes in smaller reach-in coolers and TXV in larger ones and blast chillers. We typically use automatic expansion valves (AEVs/AXVs) for wine coolers. An AEV controls suction pressure in conjunction with a TXV, which controls superheat.

Hooking up gauges is typically a last resort. We can chalk up most reach-in cooler problems to restrictions, which usually indicate cleanliness issues that are easy to solve. For example, dirty condenser coils can cause cap tube restrictions.

Control strategies vary by size, application, and complexity. For example, simple reach-ins rely on manual defrost only. However, even higher-end blast-chillers recommend manual de-icing (although they DO have defrost controls). The main defrost types are manual, fan, and electric. Smaller reach-ins have a "cold control." Cold controls are relatively simple dials that stop the compressor when the evaporator coil reaches a set temperature.

Most reach-in refrigerators are ONLY intended to hold products at temperature. With the exception of blast chillers, most reach-ins cannot bring a bunch of hot food down to temperature. These situations will result in poor performance, so customers should be aware of the refrigerator's appropriate usage.

Eric also discusses:

The troubles of charging reach-in cases
Creating your own access ports
Electric defrost in reach-in applications
Thermal imaging cameras in diagnosis
Manual defrost strategies
Pump down

Check out Eric Mele on YouTube HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Building Performance for HVAC Techs w/ Stephen Rardon and Neil Comparetto Feb 06, 2018

Stephen Rardon and Neil Comparetto join the podcast to talk about their headfirst dive into building performance as HVAC techs. They discuss jobs they do, how the transition has been, and important HVAC principles in building performance.

Addressing duct leakage can help with indoor air quality and home performance overall, but it can also even help reduce noise. Building performance and HVAC both require the serviceperson to give the customer options and inform them of their specific situation. In both cases, you would give the customer a chance to improve their living situation by offering a personalized set of offerings. However, building performance allows us to give the customer control over their comfort.

The main selling points of building performance solutions are health, comfort, and efficiency. Customer health is important because they want to make sure asthma, allergies, and other conditions won't be aggravated in their home. Comfort is important for many people, and efficiency is typically important for those with a green ethos.

If contractors and technicians want to get into building performance, it pays to take time to learn the business. It's even better if contractors put training programs together for their technicians. However, technicians need to be able to care about the material; otherwise, the investment in training may not be worth it. You must care about why we need building performance before you enter that side of the industry.

Stephen, Neil, and Bryan also discuss:

Bringing building performance into HVAC business
Blower door testing
Sales packages
System performance inspection
Challenges of growing a company
Precision manometers and other building performance tools
Zonal pressure diagnostics
Creating service departments within companies
Thinking of the building as a system
Expertise to combat automation

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Defrost in Commercial Refrigeration w/ Dick Wirz Feb 01, 2018

Dick Wirz, author of Commercial Refrigeration for Air Conditioning Technicians, talks to us about refrigerator and freezer defrost strategies. Check out Dick's book HERE.

In commercial refrigeration, we deal with much lower evaporator temperatures than residential HVAC. Although an evaporator temperature of 40°F may be commonplace in residential HVAC, you can expect evaporator temperatures from 25-30°F in refrigeration. Even though having ice on the coil is a negative thing in residential HVAC, it is perfectly normal in refrigeration.

The purpose of defrosting is to bring the evaporator temperature above freezing to melt off the frost. We can defrost a coil in a few different ways, including a mere off-cycle defrost in medium-temperature refrigeration. When the system shuts off, the evaporator coil can start defrosting. However, if too much heat is introduced to the system, more frost can accumulate on the evaporator coil. As such, a planned defrost may be in order. These defrosts occur on a timer and turn the system off overnight. Alternatively, these defrosts may use electricity or hot gas to remove ice from the coil more rapidly, especially in low-temperature applications.

Electric and hot gas defrost are common defrost types. The hot gas method generally reverses refrigerant as a heat pump does; hot discharge gas runs through the evaporator coil and melts the ice off the coil. However, hot gas is an expensive method and can negatively impact system longevity if used improperly. The electric method is cheaper than the hot gas method; this method relies on electric heat outside the coil to melt the frost from the outside.

Dick also talks about:

Warm air infiltration
Coil-sensing thermostat controls
Defrost failsafe
Defrost termination
"Snowing" in the box and fan delays
Drain pan heaters and drain complications
Paragon timers
Demand defrost setups/clocks

Check out RefTech HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bonus - What you missed at AHR w/ Bill Spohn Jan 31, 2018

In this episode, Bill and Bryan recap the 2018 AHR conference with what they learned and what you can expect to see in the HVAC/R trade in the next year. There were 2100 exhibitors who gave demonstrations and discussed products. AHR shows the real scope of the HVAC/R industry, and it is an excellent opportunity to learn more about the trade and do some networking.

At the AHR conference, there were some demonstrations that may indicate a paradigm shift in the industry's best practices. For example, the AccuTools booth projected the rate of evacuation through three hoses of different diameters, including the mythical 1" hose. The visual representation of those evacuation rates showed the trend towards faster evacuations with larger hoses. More tool manufacturers may jump on the trend to make larger hoses that assist technicians and lead to better evacuations.

The technology on display at AHR also testified to the fact that many more tools are integrating with our cell phones, including the CPS IAQ monitor. AHR also had a treasure trove of new technologies, including BluVac's Bluetooth-connected combustion analyzer. BluVac's branding is very science and engineering-focused, and they also fine-tune their technology to support techs in the field. Overall, AHR was a fantastic forum for people to spread information about products. In turn, Bill and Bryan had some of their product research validated and built upon.

Bill and Bryan also discuss:

Attaching micron gauges at the pump
Professional branding
Industry education
Surge suppressors and melting issues
The time Bill called Bryan out
Engagement with HVAC educational materials
Testo precision manometers and additional heads
Filling the HVAC/R skills gap
Increasing your value as an individual technician in this industry
Building performance in the HVAC industry
Internet of things (IoT)
The commercial HVAC market

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Intro to Pneumatic Controls w/ Jim Loring Jan 18, 2018

In today's podcast episode, Bryan talks to west-coast commercial tech Jim Loring about pneumatic controls and variable air volume (VAV) systems.

People sometimes confuse pneumatics and hydraulics. Hydraulics use liquid to provide pressure; conversely, pneumatics use air to provide pressure. Pneumatic controls use a bit more energy than other controls, but they are less costly all around. Nowadays, direct digital controls (DDCs) provide greater energy savings than pneumatics. However, pneumatic controls were a precursor to the DDC technologies we use on actuators today, and they are still a prevalent technology.

The air compressor is a critical component of pneumatic controls. That is because pneumatic controls require clean, dry air. Air compressors have an auto-drain and auto-dryer to help purify the air for peak performance. However, while air compressors are basic, their maintenance practices are often overlooked.

Variable air volume (VAV) units vary airflow throughout the building via zones. Each zone has a damper and a thermostat. The thermostats control the dampers, which control airflow to the zone and move via actuators. In a pneumatic control system, the air pressure release or gain at the thermostat moves the dampers. Thermostats also have to bleed off some of that air via direct or reverse-acting controls. Bypasses help regulate static pressure when dampers close.

Thermostats can help modulate the dampers; they don't merely open and close. The modulation occurs within a certain pressure range on a VAV system. (For example, 8 PSI would close the damper while 13 PSI would leave the damper wide open.) In addition to damper modulation, velocity controllers help control the air velocity based on signals from the thermostat.

Jim also covers:

Common air compressor problems
Pressure-reducing valves (PRV)
Restrictor tees
Direct-acting vs. reverse-acting controls
Heating and cooling in VAV systems
Damper position

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Floating Suction and Head and Rack Refrigeration w/ Jeremy Smith Jan 15, 2018

Jeremy Smith goes over floating suction and floating head refrigeration strategies. He also talks a bit more about low-ambient equipment operation.

Floating suction controls developed when we started using low-pressure controls on rack refrigeration. As the electronics advanced, we developed controls that could control temperature, which impacts pressure as well. Nowadays, controls can cross data and be much more effective at controlling pressure and temperature.

Suction pressure is the greatest contributor to a system's compression ratio. The higher the compression ratio, the less efficient a system is; a high compression ratio can be costly for grocery business owners or managers. Therefore, floating suction controls set the temperature exactly to what it should be based on the system's load, not lower than what the suction temperature should be.

Floating head controls attempt to minimize the compression ratio from the high side of the system. The floating head attempts to maintain head pressure by matching condenser fans closely with ambient temperatures. Ambient temperature controls the floating head control's set points. These floating head controls can set the condensing temperature as low as 68 degrees (F). The main factor that prevents the temperature from getting any lower is the expansion valve. It is possible that EEV usage could enable even lower temperatures, but they have been quite problematic so far. Jeremy recommends taking advantage of natural subcooling to get the most out of your floating head strategy.

These controls have to decrease capacity before they hit their targets. As such, these floating head and suction controls can be erratic and "swing" from extremes upon startup.

Jeremy also covers:

Energy and monetary savings
Pressure differentials caused by floating head controls
Expansion valves in refrigeration
Superheat "floating"
"Drain" leg or regulator

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Dehumidification Settings and Wiring with the Ecobee thermostat Jan 08, 2018

Bryan talks with Jesse and Nathan about setting up dehumidification for residential equipment in general. They also discuss some of the required and recommended settings on an Ecobee thermostat.

On typical single-stage residential equipment, dehumidification works based on CFM per ton. We control humidity by dropping the CFM across the indoor coil and extending runtime. However, as you cool the air, you reduce its ability to hold moisture. So, you increase relative humidity through cooling.

When we have achieved the desired humidity but not the desired temperature, the thermostat reduces the fan speed. Thermostats should vary the fan speed based on the call for cooling and the humidity in the air. Some systems have a dehumidification terminal; when there is a call on that terminal, the fan speed gets maxed out.

Some older thermostats would display relative humidity but did not have a dehumidification terminal; these systems would merely overcool instead of removing the humidity. These systems would be very prone to freezing. Nowadays, freezing still occurs on occasion, but our newer thermostats can control their CFM per ton much better to prevent freezing.

Ecobee thermostats work to integrate many different accessories. So, Ecobee thermostats try to solve every problem on a system, even on systems with supplementary humidifiers or dehumidifiers. These thermostats don't have a dehumidification terminal, but they have ACC- and ACC+ terminals for accessories, including dehumidifiers. Many technicians become confused when they think that the fan is a core element of dehumidification. Instead, the ACC terminals should be set as single-transformer, and you can choose the dehumidification option (which should NOT have the fan on). When wiring the Ecobee for dehumidification, connect the DH terminal to ACC+, remove the jumpers, set up the single-power source, do NOT dehumidify with a fan, and set "Dehumidifier Active" to "Open."

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What it Takes to be an Excellent Residential Service Tech Jan 02, 2018

In this episode, we cover the skills and traits needed to be the best residential service techs you can be. We follow up on the last episode's tips for getting a raise and discuss how to become more valuable as an employee.

All good service techs clearly have to be able to repair and maintain systems well. Commercial and residential techs need to demonstrate mechanical aptitude. However, soft skills are what separate the good residential service techs from the excellent techs.

Observational skills are imperative. Residential techs need to take a wide-narrow-wide approach to diagnosis. They must also utilize their senses to observe the ENTIRE piece of equipment. Observant techs are quite good at catching potential issues before they spiral out of control.

Resourceful techs make the most of the books, manuals, and other resources they have. If they don't have a resource, they find it.

Since residential service techs deal with customers, it pays for them to be pleasant with people. These people are still honest with customers, but they're positive and empathetic.

The best techs are organized and keep their tools in order for maximum efficiency.

Efficient techs increase their value as employees with every task. They become quicker as they become more confident with tasks.

Great techs are also conscientious. They are aware of their surroundings and considerate of the customer's property and feelings.

Excellent techs are also self-aware about their knowledge. They understand that they don't know everything, and they know what they have to study or search for.

Finally, the best techs are all neat, clean, and communicative. Residential service techs are our industry's ambassadors, and it is important that they communicate well AND project a good image of the industry and company to the customer.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Special Episode - How to Get a Raise, Promotion or Bonus Dec 26, 2017

As we ring in the new year, this episode focuses on how people in the HVAC/R trade can get a raise, promotion, or bonus without facing rejection or sounding selfish.

Before you think about asking for a raise or promotion, evaluate your company. Is your company pragmatic? Does the company refuse to address conflict or let tempers run high? Do your leaders care about making decisions logically and promote people who will truly help the business? A pragmatic company makes logical decisions and respects the employees who keep the business alive.

Many people want to ask for a raise when they find out that someone earns more than them or feel as though they haven't had a review in a while. People in these situations feel as though they are OWED additional pay.

Here's Bryan's advice: DON'T ask for a raise, promotion, or bonus unless you have a written salary agreement that hasn't come to fruition. When you ask a leader for a raise, you make your leaders put their guard up. In general, it's not a good idea to make someone else put their guard up when communicating with them.

If you want to talk to a leader about a plan to earn more money in the future, try to explain your vision of the future for the company; solve a company problem, or contribute to a leader's solution. Avoid self-assessments; talk about a plan or vision where YOU play an integral part in improving the company. Tie YOUR pay to the company's success, whether your solution addresses revenue, callbacks, or training within the organization.

Overall, you have to show that you're willing to accomplish a task to earn more pay. A pragmatic business will see the value in your ideas and will be more willing to give you a raise, promotion, or bonus after you execute your plan.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Single Phase, 3 Phase, and Split Phase Explained Dec 22, 2017

In this podcast episode, we discuss power distribution and some practical tips about three-phase, single-phase, and split-phase power.

The power company generates three-phase power; a power pole transformer typically has three current-carrying conductors. Each phase of power runs at 60 Hz and generates a sine wave. That sine wave peaks and valleys in a wavy formation. Power is generated in a rotating magnetic field, so it is helpful to think of a sine wave as a variation of a circle.

Transformers take high voltage and bring it down to 120V split-phase via a winding on the left, a winding on the right, and a neutral tap. The split sine waves are exactly 180 degrees out of phase; they are direct opposites, and they will intersect and both be "off" at the same time. The center is neutral. This 120V split-phase power results in 240V total; therefore, we can use them in 240V applications. Split single-phase motors require a capacitor.

Three-phase power uses all three legs of power, and the sine waves are 120 degrees out of phase with each other. In three-phase power, only one wave will be "off" at any point in time. Three-phase power is a more efficient means of running motors; split single-phase power is relatively inefficient and requires a capacitor. However, reverse-phasing is a possibility and may run motors backward, causing damage. The most common type of three-phase transformer uses the wye configuration and works for 208V applications.

Bryan also discusses:

Wye vs. delta configuration
Delta configuration high leg
Start assistance and capacitors
Residential vs. commercial applications
Capacitor failure
277V and 480V applications
Replacing single-phase with three-phase power or vice versa
Three-phase condensers with single-phase air handlers

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Desiccant Dehumidification w/ Tom Peterson Dec 18, 2017

Learn about large-scale desiccant dehumidification from the expert, Tom Peterson. Tom works with CDI (Climate By Design International).

Dehumidification has several different methods and applications. Cooling is the most basic of those methods, but it has its limitations. For example, dehumidification by cooling may leave moisture on the coil and lead to freezing. Desiccant dehumidification can remove water from the air without the possibility of freezing the unit.

Desiccants are crystalline structures with pores, and they remove moisture via adsorption. Water has a pressure that pushes other water molecules into those pores. Partial pressures also help force the pressures from high to low. Moisture will only come out of the desiccant upon heating the air around it. Heat excites the water molecule that has been trapped in the desiccant pore, so that molecule breaks the bond between itself and the desiccant (desorption).

Commercial/industrial dehumidifiers make use of desiccants. Desiccants fit into rotors or wheels, and air passes through the desiccant rotor. The goal is to dehumidify and only dehumidify. So, no heat transfer occurs as air passes through those desiccant rotors. About 3/4 of the rotor works to adsorb moisture, and about 1/4 of the rotor works to desorb moisture.

We measure moisture in a unit of weight called grains per pound of dry air (simplified to "grains"). Grains refer to moisture rather than a humidity percentage, but grains and humidity are indeed linked. Even though we attempt to reduce grains per dry air, we cannot have negative grains of moisture; it is an impossibility.

Tom also discusses:

Sensible vs. latent heat
Grain depression
Dew point

Learn more about desiccants at the CDI website at cdihvac.com and their YouTube channel HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Compression Ratio, Heat Pumps and More w/ Carter Stanfield Dec 11, 2017

Carter tells us why compression ratio is important, what it means, why it changes so much on heat pump systems, and the effect it has on system operation. We also talk a bit more about heat pumps and their unique challenges beyond compression ratio.

Compression ratio is a comparison of discharge pressure to suction pressure. A ratio of 3:1 indicates that the discharge pressure is three times higher than the suction pressure. The higher the pressure difference, the less gas you move and the less efficient your system is. The compressor has a fixed volume, but the gas's actual mass varies based on density and pressure. So, lower suction pressure results in less gas being moved. Dirty filters, coils, and other means of clogging the system can drastically increase the compression ratio.

Heat pumps are especially sensitive to compression ratio changes because they move varying amounts of refrigerant depending on the operating mode. As such, charging heat pumps can be a challenge. Some heat pump manufacturers use a charge compensator to help make charging a slightly less difficult task. Heat pumps may also have coils with smaller surface areas, which can drive up the compression ratio.

Heat pumps have highly variable evaporator temperatures, and refrigeration systems have highly variable condensing temperatures. Both of these highly variable conditions may indicate systems with susceptibility to high compression ratios. In the case of refrigeration systems, the metering devices are critical components for reducing keeping the compression ratios at bay.

If you cannot find manufacturer literature or are working on an old heat pump, Carter recommends using airflow and temperature difference to determine how much heating the system is accomplishing.

Carter and Bryan also discuss:

Rheem and Ruud heat pumps
Centrifugal blowers
Plenum placement
New inverter-driven compressors

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Using Volts and Ohms in Diagnosis Dec 05, 2017

In today's podcast, Bryan talks about voltage (volts) and resistance (ohms), specifically using a voltmeter and an ohmmeter for diagnosis. We also discuss voltage drop.

In many cases, Ohm's law is impractical for field usage because of the additional resistance from inductive reactance. We also don't typically measure impedance and only care about resistance on the windings. However, Ohm's law is still a valuable concept because it teaches technicians the relationship between voltage, amperage, and resistance (ohms).

Ohm's law states that volts equal amps multiplied by ohms (E = I x R). Therefore, if the volts stay constant, ohms will increase as amps decrease and vice versa.

We distinguish lines from loads in circuits; we say that loads are the parts that "do" something due to resistance in a circuit. There are two kinds of loads: inductive and resistive. Inductive loads generate expanding/collapsing magnetic fields, which can also cause rotational force or activate a solenoid. Resistive loads generate light and heat, so heat and resistance are related.

Of course, the diagnostic tools we use (multimeters, voltmeters, ammeters, ohmmeters, etc.) also have their limitations. A voltmeter merely determines a difference in charges between two points. When using a voltmeter on a low-voltage circuit, try to plant one of your leads on the common side and take readings throughout the circuit with your hot lead. Ground is also NOT a reliable reference point for diagnosis.

The point of measurements is to prove what we suspect to be true; we must understand what our data mean for system operation and what our tools' diagnostic limitations are. For example, when we ohm out contactors, we check to see if they're open.

Bryan also discusses:

Fixed wattage or resistance
Reading between wires
Meter lead placement
Amperage (dynamic current/electrons)
Undiagnosed shorted circuits
Contact points
Voltage drop and resistance
Infinite ohms
Wire length

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Variable Speed Motors and Why They Matter w/ Jamie Kitchen Nov 27, 2017

Jamie Kitchen from Danfoss talks all about variable-speed motor technology. He discusses why those motors exist, what they do, and how to think differently about the future of HVAC/R.

Most techs think about variable-speed motors as the X13 and ECM blowers in residential applications. Those motors can adjust their performance based on ambient temperatures and moisture levels. So, variable performance may result in better comfort and efficiency.

ECM motors adjust airflow based on sensor inputs, especially dehumidification calls. The sensors may pick up both sensible and latent heat content. Sensible heat is what we can feel (dry-bulb temperature). Latent heat refers to moisture in the air (humidity, wet-bulb). ECM motors adjust their speed based on data from both, which is highly beneficial for greater comfort in the home. Human comfort is a lot more complex than feeling satisfied with a single number on the thermostat; ECM motors help control humidity and give you more leeway over selecting an acceptable dry-bulb temperature of a space.

Variable-speed motors exist on the commercial side of the HVAC industry as well. Commercial HVAC equipment brings in more fresh air and is overall less restrictive than residential. A variable-speed motor can help manage the latent heat of fresh air and work as a form of air treatment. Variable-speed motors compare indoor and outdoor conditions to treat the fresh air and maintain the indoor conditions. These motors account for sensible and latent heat loads, just like the residential ECM motors, and they adjust themselves constantly.

Jamie and Bryan also discuss:

Capacity and heat profiles
X13 motor controversy
Having multiple variable-speed components in a system (compressor, blower, etc.)
Sensible heat ratio (SHR) and heat load matching
Complex human comfort
Reheat coils
Air treatment requirements

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Duct Design Facts w/ Jack Rise Nov 23, 2017

Jack Rise returns to the podcast to share some duct design facts with us and talk about his Manual D book on the ACCA website.

Before we can even start thinking about duct design, we need to think about the total effective length; even before that, we also need to think about finding the critical path. The critical path is the path with the greatest resistance to airflow (from the return to supply); the fittings in the critical path contribute to the duct's total effective length.

Flex duct is a controversial and somewhat complicated building material. It's common in Florida, but Jack doesn't use it in his duct designs; he can't depend on others to install it properly. Very few people tend to install flex ducts as tightly as they probably should.

Noise is a problem for ducts, and takeoffs on the plenum are a significant contributor to noise issues. Instead, Jack suggests having a takeoff from the collar that goes straight into the appropriately sized duct for the desired airflow. (It's also worth noting that noise is subjective and is difficult to measure.) It's also unwise to position two takeoffs directly across from each other, as noise travels across those.

The rise of indoor air quality (IAQ) products also requires us to look at duct design facts. Filtration improves IAQ but increases static pressure and can impede airflow. We need to be able to plan for IAQ products when we design ductwork.

Jack and Bryan also discuss:

Selecting the equipment location and position
Balancing damper placement and leakage
Radial systems and symmetry
Plenum sizing
Why panning is not great (and illegal)
Why bay jumping is a bad idea
Duct design vs. truss positioning
Airflow in the occupied zone

Check out Jack's book, Understanding Manual D, HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Removing Gas Meters and Heat pumps in Cold Climates w/ Nate Adams Nov 17, 2017

Nate Adams joins the podcast to describe the method behind his madness of removing gas meters and installing heat pumps in Ohio. Nate is in the home performance business, and he focuses on its intersection with the HVAC industry

We typically find heat pumps in milder climates, so removing gas meters and replacing them with heat pumps is a bold move in cold climates. However, high-performance heat pumps have inverter technology, which allows them to run in colder climates without freezing over in the snow.

Nate predicts an eventual switch to heat pumps from fossil fuels. Heat pumps that rely on geothermal, solar, and other renewable energy sources will be much better for the environment than natural gas and oil. Backdrafting and CO issues are also nonexistent in heat pumps. However, we also have to consider domestic hot water and other appliances that use natural gas when we switch homes over to heat pump technology. When colder climates embrace electric heat pumps, they will have to prepare for increased dehumidification needs due to the moisture in the air during the spring and fall.

According to some tests run by Nate, fully electric systems model nicely and perform on par with gas furnaces in his Ohio climate. However, some people may object to heat pump installations because they prefer the comfort of gas furnaces. When you look at mean radiant temperature (MRT), surface temperature contributes most to human comfort. In that case, BTU output and load matching are what really matter, not the system type.

Nate and Bryan also discuss:

Equipment sizing for load conditions
Split systems and backup heat
Being theoretical vs. using real data
ACH50 vs. CFM50
High-efficiency furnaces and combustion air
Determining surface temps and MRT
Startup and commissioning of high-performance heat pumps
Dehumidification and reheat systems

Learn more at energysmartohio.com and natethehousewhisperer.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Leak Free Systems w/ Bill Johnson Nov 13, 2017

Bill Johnson is one of the great educators and writers of our time in HVAC/R. In this podcast episode, he shares some information about his career and some of his top tips on keeping systems leak-free.

Bill began his work on leak-free solutions by using Glyptal on centrifugal compressors. The Glyptal would harden around leaks and seal them up. Nowadays, this is an ineffective approach to sealing leaks in higher-pressure systems.

Bill got the idea to start manipulating pressures to minimize leaks with a standing pressure test for 24 hours at the highest test pressure recommended by the manufacturer. That is Bill's best practice, though it is not always feasible. Bill's rationale is that leaks become much more evident under those testing conditions. (Remember, pressurize the line set. Pressurizing the system can be a bad idea.)

On top of that, Bill recommends pulling a deep vacuum and performing a standing vacuum check according to the manufacturer's guidelines. Fitting inspections are also critical; fittings may be sealed imperfectly, and they are common leak points. Check fittings with a mirror and a good light to look for imperfections and cracks.

Leaks generally occur in piping, not the equipment itself. Moreover, vibrations and corrosion generally cause leaks.

Begin a leak inspection by leak-checking the gauge ports BEFORE attaching gauges. In general, inspect the entirety of the equipment with your senses before attaching gauges. When leak-testing with soap bubbles, make sure to use one that doesn't need to be washed with water, as water can lead to corrosion. (We recommend Refrigeration Technologies Big Blu.)

Most of all, don't leave a job until you find a leak or confirm that the system is leak-free!

Bill also discusses:

Being an HVAC teacher
Critical charge leak detection
Pressurizing with nitrogen
Misleading leak detection equipment
Torque wrenches

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Furnaces - Introduction and History w/ Jim Bergmann Nov 09, 2017

Jim takes us all the way through the history of furnaces, from the Stone Age when he was a child to modern modulating condensing types.

The goal of a furnace is to move heat, so a furnace uses heat exchangers to facilitate heat transfer. Furnaces have primary and secondary air. The primary air goes through the burner, and the secondary air goes around the flame and is pulled in around the heat exchanger inlet. So, the flame's heat creates a draft that pulls air in.

Natural gas and oil (LP/propane) furnaces are common nowadays, but we initially burned wood and coal in furnaces. The first gas furnaces came into existence by modifying coal, not from the gas lines we see nowadays. Long ago, the flue gases were also exhausted to the basement; CO poisoning was less of a concern back then, as combustion was usually complete. Burning the building was a much more severe risk.

The first "gas crisis" in the 1970s forced us to focus on gas furnace efficiency. In that time, we developed spill switches and retrofit kits that converted furnaces over to spark ignition. In the 1980s, we came out with the draft-induced 80% furnaces we see nowadays. We also eliminated standing pilots and draft diverters. Even though the appliances became more efficient, we didn't actually burn the gas any more efficiently.

So, despite the technological advancements we've made over the years, we don't actually burn gas any more efficiently than we did in the 1930s. However, our modern furnace technology has eliminated standby losses, controlled ignition, and focused on the role of latent heat in combustion.

Jim also discusses:

Flame color and types
Draft hoods and diverters
Products of complete combustion
Excess air: a double-edged sword
Natural ventilation
Efficiency percentages
Furnace testing and ratings
Turbulators
Modulation

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Electrical Circuits Class Nov 07, 2017

This podcast episode on electrical circuits is a class recording. In it, Bryan discusses transformers, ground, common, and line vs. load sides of a circuit.

Transformers use induction to pass alternating current signals to electrical appliances. Alternating currents (AC circuits) are tricky because the current switches direction each time. Therefore, the current flow is difficult to visualize because the direction keeps changing. Electrons naturally want to go to the other side of the transformer, not to ground. So, we have to connect both sides of the transformer to ground to send electrons to ground. (In this case, ground refers to the metal body of equipment, not the earth.)

A "short" is an undesigned path, typically taken at high current due to low resistance. The high current can blow fuses and cause equipment failure. Therefore, we connect to ground to prevent that high current from taking paths that will cause equipment failure.

The part of the circuit that we call "hot" is on the line side of the switch. That part is the line that goes into the switch. The part of the line that leads from the switch to the load is called the load side. After the load, we have "common" or "neutral." When common is connected to ground, it will be electrically the same as ground. However, it's worth noting that "common" can mean several different things in electrical. (Typically, we call common "L2" in high-voltage circuits with multiple phases, "neutral" in 120v circuits, and "common" in low-voltage circuits.)

Bryan also discusses:

The downsides of memorizing wire colors for making connections
"Common" misconceptions
Switch types in electrical circuits
Thinking of connections as a switch and load
Various terminals and wires

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Electrical Basics: How and Why Electrons Move Nov 03, 2017

In HVAC work, we deal with quite a few electrical components. But where does electricity come from? Why do electrons move? In this podcast episode, we talk about differential charges, sine waves, and some voltage measurement basics.

A large chunk of electrical theory is centered on electron movement. We get electrons to move with differentials in charges or energy states. Nature tends towards equilibrium, so electrons will move to restore a state of balance. A battery or transformer does not create energy; they create energy imbalances that cause electron motion to occur. Alternating current (AC) creates a differential by reversing the direction of current several times per second. Transformers and motors use AC power and inductance to drive HVAC systems.

When testing with a voltmeter, you're looking for a difference in charges. So, the probe placement matters. When you have no difference in charges, no electrical work is being done.

Most of the power we use comes from power plants. At these power plants, rotating magnetic fields generate the power we use. Power generated through magnetism creates a sine wave. A sine wave is a variation of a circle; the wave goes up and down in a cyclical pattern. So, you can look at sine waves and determine exactly how legs of power are out of phase with each other. For example, single-phase power comes in and splits at the transformer, creating an opposing sine wave that is 180 degrees out of phase with the power leg (when one wave peaks, the other valleys).

There is also some confusion surrounding "neutral" and "ground." Ground is merely a conductor for safety reasons and has nothing to do with electrical operations; the ground does not generate electron movement. Neutral is NOT the same thing; neutral is a circuit conductor, but we usually connect it to ground.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Duct We Tend to Forget w/ Joe Medosch Oct 29, 2017

Do you think of the building envelope as a duct? Do you test it? In this podcast episode, Joe Medosh talks to us about envelope testing and why it’s the future of building health and comfort.

The building envelope is the largest duct in the entire home. However, so many HVAC techs forget about it; they attempt to optimize comfort in the HVAC system and ducts, not the home itself. Techs use Manual J and S, but they don't use the infiltration rate in their calculations. Infiltration in the envelope is a major culprit of discomfort in the home, especially through and around windows.

We use blower doors to determine leakage. During the blower door test, we depressurize the home by a pressure difference of -50 Pa, and we can then calculate the air changes per hour by taking the CFM, dividing it by the volume, and multiplying that number by 60.

The pressure pan is another tool that we use to determine leakage. Pressure pans are semi-quantitative tools that help you figure out where leaks are coming from; you won't find out how much CFM leakage you have, but you will find out if there is CFM leakage.

The commercial HVAC industry has already used "fresh air" in buildings via economizers. However, the residential HVAC industry does not bring fresh air in via the HVAC system. Joe proposes solutions to seal homes but allow fresh air to enter the home in a controlled manner; when we bring that fresh air in, we could implement dehumidification measures to avoid fungal growth.

Joe also discusses:

Windows and energy savings myths
Measuring volume in the home
Common sources of leakage in the home
Gas appliances and combustion/CO risks in tighter homes
Outdoor air and retrofit applications
Backdraft
Balancing ventilation

Check out Retrotec at retrotec.com or purchase Retrotec products from TruTech Tools at trutechtools.com/retrotec. (Use the code "getschooled" at checkout for a discount!)

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Ductless Maintenance Steps - Part 2 Oct 23, 2017

Ductless expert Jesse Claerbout talks about his best maintenance practices for ductless air conditioners and heat pumps. This episode is part 2 of the two-part series.

Ductless outdoor units tend to have clean condensing coils. The only real issues are grass clippings (and cottonwood, in some locations). which typically don't affect performance too sharply. Jesse likes to clean outdoor units with plain water; he does not use cleaners.

Drain cleaning is a little more involved than condenser cleaning. When cleaning a gravity drain, Jesse uses a shop vac to get rid of standing water. He does not run water through the drain line until after he begins reassembling everything after cleaning.

Three main lines need to be insulated: the suction line, expansion line, and drain line. A proper ductless maintenance procedure will include checking the state of those lines' insulation.

Condensate pumps can be a necessary evil in ductless unit maintenance. The cleaning procedure is straightforward, but it requires a lot of work and leaves plenty of room for techs to cut corners. Much of the difficulty comes from exposing the reservoir, which is the component that truly needs cleaning. You can clean it from the poly-tubing, but you must use a shop-vac to clean it thoroughly.

When you finish, make sure that the blower wheel sounds right and that no parts are rubbing against each other. Let the unit run for 15-20 minutes before taking line temperatures so that all the parts can dry. Check the charge (preferably without gauges), air temperature split, and your amperage to make sure that the unit works as it should.

Overall, the most important goal of ductless maintenance is to establish a cleaning regime that works for your business and the customer.

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Ductless Maintenance Steps - Part 1 Oct 20, 2017

Ductless expert Jesse Claerbout talks about his best practices for maintaining ductless air conditioners and heat pumps. This episode is part 1 out of 2. Ductless maintenance can be a bit more extensive than regular split system maintenance.

Ductless filters are plastic; they are not high-MERV and can simply be washed off with water. Customers can clean their own filters with nothing but water from a hose or sink.

Blower wheels are a bit more challenging than filters; the blower wheels are long, have small cups that are prone to buildup, and carry an electrostatic charge. Due to the blower wheels' challenging nature, technicians require special training to deal with the additional labor, and customers require special education. As such, we at Kalos charge for special blower wheel maintenance. We pull the blowers from the systems and clean them (though the process of getting a blower wheel off the blower shaft is complicated). You can wash the blower wheel outside with a safe cleaner; make sure the wheel is dry when it goes back inside.

Removing the blower wheel gives you full access to the drain pan. During a ductless maintenance procedure, remember to clean out the drain pan thoroughly with a safe cleaner. If you clean ANY component indoors, use a drop cloth, especially if you're cleaning on carpet.

We clean evaporator coils and the housing with spray bottles (preferably) or pump sprayers. Clean WITH the grain, not against it, and use only water or mild, non-toxic cleaners. A botanical cleaner works well, especially for customers who may have allergies. Rectorseal also has a cleaning kit (Desolv) that comes with a good coil cleaner, a cleaning bib that surrounds the ductless unit, and a pump sprayer.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Run Capacitor Facts You May Not Know Oct 18, 2017

In this episode, we cover some common misconceptions about run capacitors, some easy ways to test them, and some tips on working with them.

A run capacitor is a power storage device; it contains oil to dissipate heat and some thin metal plates wrapped in a spiral. Capacitors also contain plastic insulation between the metal plates to keep the power separate; electrons should NOT cross the insulation, and there should be a charge difference between the plates. Current also does NOT flow through the capacitor; capacitors merely store and discharge power.

Capacitors also do NOT boost voltage. You may notice higher voltage between terminals, but the capacitor is not involved in that voltage boost. You see that voltage increase because of the inductive motor's back EMF. Back EMF only occurs on systems with a running motor.

On a single-phase PSC application, the run winding is the primary, and the start winding is the secondary. A run capacitor that is too large will draw more current on the start winding. You may see a slight drop in overall amperage on the common wire, but large capacitors increase the current on the secondary winding. The start winding is not designed to carry excess current.

Connecting capacitors in series REDUCES capacitance. Therefore, most of the time, we connect capacitors in parallel. Many electrical circuits nowadays are connected in parallel (compare to Christmas lights, which are connected in series).

Bryan also covers:

Capacitor basics (terminals, microfarads, etc.)
"Common" confusion
Capacitance and current relationship
Start capacitors and potential relays
Hard start kits
PTCR products
Series vs. parallel capacitors
Testing capacitors (in the circuit, under load, with a capacitor tester, etc.)
Calculating capacitance and evaluating capacitance ratings

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bonus - The Case for Tamper Resistant Caps w/ James Bowman Oct 11, 2017

James from Rectorseal talks about the IMC codes relating to tamper-resistant caps and why you may consider installing them now.

Tamper-resistant caps, also known as locking refrigerant caps, fit on refrigerant ports to prevent unauthorized access. Even though these caps can RESIST attempts to tamper with the equipment, they are not (and cannot be) fully tamper-proof.

Many new construction companies used to put the caps on ONLY to pass inspection; they then take the caps off to reuse them several times. That's an inhalant abuse risk, and it's also a liability issue for other contractors who service the equipment. So, the IMC requires locking-type, caps to be fastened to the equipment after charging or recovery. Unfortunately, it's impossible to enforce the code, even as it currently stands.

Moreover, many technicians want manufacturers to make their equipment easier to service. Components like tamper-resistant caps make it harder to service equipment. Almost no standard tools can remove those caps, and you will need special tools for tamper-resistant cap removal. The code, however, does not define what a "tamper-resistant" cap is; a key could fall under that umbrella.

However, tamper-resistant caps are still worth considering because they prevent inhalant abuse. Inhaling refrigerants is a gateway for harder drugs, including heroin. Even though tamper-resistant caps may not stop adolescents from doing drugs at all, we remove our industry from that controversial subject. It is also a good idea to give your system caps that make it harder for people to steal refrigerant, especially as refrigerant prices rise.

James also discusses:

The purpose of code commentary
Inhalant abuse prevention
Code compliance
Built-in vs. added components required by code
IMC vs. AHD
Explaining tamper-resistant caps to customers

Check out Rectorseal's Novent refrigerant caps HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Economizer Basics w/ Jerry Eavenson Oct 10, 2017

Many techs know just enough about economizers to bypass them. In this podcast episode, Jerry Eavenson and Bryan talk about the basics of what an HVAC economizer is and how it functions.

Economizers typically work on the air side of package units and help pull fresh air into a structure. Economizers are almost exclusive to commercial HVAC. Climate also plays a role in their usage; you will not find many economizers in hot and humid places like Florida.

An economizer is generally an energy-saving device that brings fresh air into a building if it is of a higher quality than the return air. These economizers determine if the outside air is better than the return air via enthalpy controls. Enthalpy controls evaluate the humidity and temperature of the air.

When you set up an economizer, you can easily go wrong if you don't understand the sensors that are involved in the setup. Many economizers have dry-bulb or enthalpy sensors (wet-bulb), and these sensors are not interchangeable. You typically have to know the model number to differentiate the two types, but the model information is readily available on the internet. Typically, your differential set points will depend on your climate zone. You may come across fixed-enthalpy or differential controls.

When it comes to economizers, acquiring documentation is the best move. As with all types of HVAC equipment, reading the manual is the key to understanding what an economizer does. Jerry recommends identifying the controls, sensors, and functions of the equipment. Economizers may vary greatly across models within a manufacturer (let alone across manufacturers).

Jerry and Bryan also discuss:

Heat loads of commercial spaces
Variable frequency drives
Sensors
Economizer setup
Honeywell Jade
Cooling stages
Controls
Dehumidification-only application possibilities
Return duct sizing
Climate zones

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

A Steam Heat Primer by Dan Holohan Oct 07, 2017

Dan Holohan is the father of modern steam heat training. This episode is a narration of his in-depth steam article "A Steam Heating Primer" from HeatingHelp.com.

Read that article HERE.

Check out more about Dan's work at heatinghelp.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Lost Art of Steam Heating w/ Dan Holohan Oct 03, 2017

In today's podcast, Bryan talks with legendary Hydronics author and trainer Dan Holohan about the history of steam heating and some practical applications of old ideas. Recently, Dan has been working on more novels, having published two of them over the past few months.

Dan also discusses:

The 2-PSI standard
Transportation metaphors for BTUs in steam
Harmful renovations for old boilers
Replacement vs. restoration mindsets
Gaps in steam boiler education
Monopolizing the market if you HAVE the education
Boiler piping and venting
Two-pipe vs one-pipe steam

Find out more about Dan and hydronic heating at HeatingHelp.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bonus - The Spark Ranger Sep 30, 2017

This special podcast episode focuses on the tragic life and times of Spark Ranger Roy Sullivan.

Roy Sullivan was a park ranger who was born in Virginia in 1912. He grew up in the 1920s when the mining industry was in full swing and had scrapped up the beautiful mountain landscape. In 1935, Shenandoah National Park was founded, and Roy decided to become a park ranger. He wanted to help restore the land and protect it from human destruction, such as the mining industry.

One of Roy's duties was to scope out the forest on the new fire lookout tower. That new tower had yet to have a lightning rod installed. One day, a lightning storm approached while Roy kept watch, and lightning struck the tower. Roy survived the strike, though he was badly burned in the incident.

In July of 1969, Roy encountered lightning once again. That time, Roy was driving a car. Although many people believe that the tires are insulators, most people are protected from lightning by the Faraday Cage effect; the current travels through the metal around you until it reaches the ground. Roy, unfortunately, forgot to close his window and had a lightning charge from a nearby tree strike him through the window.

Roy got struck with lightning yet again while doing yardwork a little while later after a transformer was struck by lightning. He was allegedly struck by lightning several times after that, including on a fishing trip where he ALSO had to outrun a bear after getting struck by lightning. However, even though Roy had the scars, these lightning strikes are unconfirmed.

Sadly, Roy died by a[n allegedly] self-inflicted gunshot wound. However, the legacy of the Spark Ranger continues through his ongoing world record for "Most Times Struck By Lightning."

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Electronic Expansion Valves (EEV) w/ Jamie Kitchen Sep 27, 2017

In today's podcast, Bryan and Jamie talk about the electronic expansion valve (EEV). Bryan and Jamie describe how EEVs work and the reason they exist. In the process, the hosts also review a wide range of metering devices. We made this podcast to address the rising demand for EEVs in the aftermarket element of the HVAC business.

Like the TXV, the EEV is a metering device. Metering devices create a pressure drop as refrigerant moves from the liquid line to the evaporator. Traditional refrigerators typically use capillary tube metering devices because they require a constant temperature and operate in a fixed temperature environment. However, TXVs are a bit more variable but open linearly and are dictated by a minimum stable superheat value. EEVs are also variable, but they can influence the superheat more directly; the superheat always exceeds the minimum stable superheat. Therefore, EEVs can increase efficiency by reducing the evaporator temperature and compression ratio by increasing saturation temperature.

Even though EEVs dominate the grocery refrigeration market because of their head pressure control, we can use them in residential HVAC too. The EEV controls superheat more precisely than a TXV, and their algorithms can maximize efficiency and fill the evaporator coil with the most refrigerant possible.

There are two types of EEVs: the pulse-width EEV and the stepper motor EEV. The stepper motor has "steps" to modulate the degree to which it opens or closes. The pulse-width EEV either opens or closes, much like a solenoid valve.

Bryan and Jamie also discuss:

Hot pull down
Ideal compression ratios and efficiency
Minimum stable superheat
Compressor cooling accessories
Downsides of oversizing TXVs
Evaporator superheat vs. suction superheat
Technological advancements for EEVs, especially for Danfoss EEVs
Less obvious advantages of EEVs over TXVs

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

(Bonus) HVAC/R Industry State of the Union Sep 22, 2017

In today's podcast episode, trade school student Chris Caldwell interviews Bryan about trends in the HVAC industry, his business, and the future. Chris works in the HVAC business as a service tech and attends trade school in Alabama.

New trends include spending more money on testing instrumentation. Nowadays, there is a greater reliance on test instrumentation to produce accurate measurements. Diagnostics have certainly improved over time. On top of that, Bryan sees the industry's potential to improve other practices like evacuations.

Customers have paid more attention to indoor air quality recently, and that trend is likely to continue. There is a new emphasis on comfort over energy efficiency, especially in humid climates like Florida and Alabama. As such, HVAC techs can expect an intersection between the HVAC industry and the building science industry. Customers also enjoy having integrated controls, such as thermostats that connect to wi-fi.

However, some service companies and manufacturers have focused too much on shiny new technology. Bryan owes this phenomenon to the "sales-first" business model. He would prefer to see techs and manufacturers focus on basic serviceability. As such, Bryan would like to see an emphasis on creating thorough solutions to problems instead of seeking quick fixes.

In the future, Bryan hopes to see further development of tools like measureQuick. He would love to see better data collection practices. He would also like to see more unified communication protocols between appliances.

Bryan and Chris also discuss:

Solar solutions
Human comfort and IAQ
Communication between techs in the digital age
New ASHRAE outdoor air standards
"Sales-first" business models and the skills gap
How to make the HVAC industry appeal to the new generation
How to find fulfillment and validation in HVAC work

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Filter Drier Basics w/ Chris Reeves Sep 19, 2017

In today's podcast, Chris Reeves joins Bryan to discuss filter driers, including suction driers, liquid driers, core driers, different media, and basic applications. Filter driers are simple components, but they have plenty of room for misunderstanding within our trade. We refer to Parker-Sporlan Bulletin 40-10 throughout the podcast, and you can read that bulletin HERE.

Above all, filter driers act as filters that prevent debris from reaching the expansion valves and destroying them. As such, the best place to install a liquid filter line drier is as close to the expansion valve as possible. These filter driers also catch and hold water from the system; they minimize moisture to keep HVAC systems functioning properly. Filter driers also catch and remove acids from the refrigerant circuit. A filter drier and its desiccants CANNOT remove non-condensable gases.

However, filter driers should NOT be the primary method of removing moisture. Proper evacuations with deep vacuums should be the main method, as filter-driers are limited in their moisture removal capacity. You also don't want to use a filter drier that has been exposed to atmosphere any longer than a few minutes; the drier has had time to collect moisture and will be less effective. Each time you open up a system, removing the filter drier is the best practice.

We use biflow filter driers on heat pumps. The refrigerant can flow in both directions; a check valve directs the flow, so the flow always goes through the core and filter pad the same way, regardless of operation mode.

Suction line filter driers are for older HVAC systems with issues. You'll want to install them close to the compressor for maximum protection and watch the pressure drop across the drier.

We also discuss:

Temperature control
Overheating driers and exposing them to heat
HH-style filter driers (with activated carbon)
System sizing as a consideration
Burnout and contamination

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Nitrogen Pressures do Change with Temperature - the Basic Gas Laws Sep 16, 2017

In today's podcast, Bryan covers the four basic gas laws and how they apply to you as an HVAC technician in the field, not just in theory. Remember, when dealing with pressure, you must convert the units to PSIA, not just PSIG. To do that, you merely add 14.7 to your gauge pressure.

In every equation, the "1" indicates an original value, and the "2" indicates a new value.

The simplest of the gas laws was discovered first, Boyle's law. The law states that there is an inverse relationship between absolute pressure and volume. When a gas's pressure increases (such as via compression), you decrease its volume. Inversely, when you decrease a gas's pressure, that gas will expand, and its volume will increase. Mathematically, the law looks like this:

P1 x V1 = P2 x V2

Charles's law focuses on volume and temperature. This gas law states that volume and temperature rise or fall together so long as the pressure stays the same. You can mathematically describe the law with the following equation:

V1 / T1 = V2 / T2

The general law of a perfect gas combines Boyle's and Charles's laws. You can mathematically describe the law like this:

(P1 x V1) / T1 = (P2 x V2) / T2

As HVAC technicians, we should care about the gas laws because our pressures and volumes will change as temperature changes throughout the day, such as when doing a standing pressure test with nitrogen. Nitrogen is a relatively non-reactive gas, so it will follow the gas laws and won't condense to a liquid or react with other chemicals.

Dalton's law is the final law, and it states that the combined pressure of all gases in a closed space is equal to the sum of the individual gas pressures.

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Bonus - Tips from a VRF Tech w/ Alex Figueroa Sep 15, 2017

Alex Figueroa is a VRF and refrigeration tech in Puerto Rico, and he talks to Bryan about his work and specialized experiences. Since Mitsubishi is a forerunner in the ductless industry, many of the units that Alex has worked on are Mitsubishi units.

Alex works on lots of ductless mini-splits and VRFs in central air in commercial buildings. He typically works on VRF units that have ceiling cassettes or fan coils. Some VRF units also have branch boxes with electronic expansion valves (EEVs), and those components help distribute refrigerant flow. These systems have expansion lines, which some technicians may confuse for liquid lines.

As with other large commercial HVAC units, oil is also a concern in VRF systems. Smaller-tonnage systems have large accumulators, but larger systems may also have large separators. Some of these systems are large and may contain 200-300 pounds of refrigerant. Unlike many other HVAC units, these systems have an electronic interface that indicates superheat, subcooling, and other criteria that can help with charging and troubleshooting. (Techs can, however, hook up gauges at the condenser, but the practice is not often necessary.)

When you open up a VRF system for the first time, you will see lots of solenoids and other components that resemble refrigeration parts. Therefore, Alex felt that his experience as a refrigeration technician benefited him as he began working on VRFs. Like heavy refrigeration (especially grocery refrigeration), VRF systems may have several compressors and refrigerant circuits in a single system. Digital scrolls are common compressor types for these systems.

The greatest maintenance issues with VRFs deal with are dirty evaporator coils and filters. In Alex's experience, the electric controls are the most commonly failed component.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Ductless and VRF Diagnosis w/ John Chavez EP2 Sep 12, 2017

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, longtime VRF/ductless pro, covers his approach to ductless and VRF diagnosis in Part 2 of this podcast. (Listen to Part 1 HERE.)

If you believe that there is a component failure, you'll want to check the voltage going into the unit. You'll want to pay special attention to the board and see where power is going in and out. In other words, pay attention to your inputs and outputs on the board and pay attention to the documentation in the manual. Make sure you have a quality voltmeter on hand.

Another potential electrical issue occurs when the board blows out entirely. When that happens, you'll have to watch the input voltage and be mindful of the utility quality and local geography. Utility companies WILL NOT admit if they are part of the problem, so it is good for a technician to ask about the property and utilities to study the history of the unit and the location.

Watch your discharge air temperatures and make sure they perform correctly under AHRI conditions (the standard is 95 degrees outdoors, 86 degrees indoors); should have 40-50 degrees coming out of the discharge of the ductless unit. Pipes may even get as cold as 37 degrees before discharge protection kicks in.

To sum everything up about VRF diagnosis, you'll want to do whatever you can to find the root cause; don't be a parts-changer. To consider all possibilities, you must take your time to understand the unit.

We also discuss:

Lightning strikes and power surges
Determining delivered capacity
Critical charge
Electrical/controls terminology
Building science, thermal envelopes, and VRF performance
Sensible and latent heat loads
Inverter-driven compressors

Resources

Computer Room Application Formula

Ductless Steps

Friedrich Service Form

Seven Common Install Answers

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Matter, Mass, Weight, and Volume Sep 11, 2017

This episode covers some basics of matter that relate to HVAC/R. These basics include mass, weight, and volume. There will also be some talk of specific gravity and specific volume.

Matter and energy are the building blocks of the HVAC industry; we move matter around and transfer energy. Matter refers to anything that exists and takes up space, including all solids, liquids, and gases. We use three means of measuring matter: volume, mass, and weight. Volume refers to how much space an object occupies. Even though we use mass and weight interchangeably, they mean two different things. Mass refers to the amount of matter an object has, and weight is the force exerted on an object by gravity.

Density is a mass-to-volume relationship. Density comes into play when items float or sink in water, and it is a component of specific gravity. Specific gravity does not have an absolute unit of measure; it merely compares an object's density to water. For example, propane has a specific gravity of 1.5 in comparison to air and would sink. Conversely, natural gas has a specific gravity of 0.6-0.7, meaning that it would float in air.

Specific volume is NOT relative; we use a set unit for it, typically cubic feet per pound. The cubic feet of air per pound changes with temperature, humidity, and barometric pressure. So, "standard air" isn't a fixed value. All gases can be compressed and can be affected by temperature much more easily than the other states of matter. Specific volume is important because it helps us determine the amount of refrigerant we can safely put into a recovery tank; you must know the difference between the specific volume of water and the refrigerant you are using.

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Ductless and VRF Diagnosis w/ John Chavez EP1 Sep 09, 2017

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, a longtime VRF/ductless pro, explains his approach in Part 1 of this podcast.

You CANNOT have a haphazard approach to installation or service. The best thing you can do is respect VRF and ductless technology for what they are. When you take the time to understand the equipment and the processes at work, you will be successful. The best thing you can bring to a job is patience.

Unlike on typical split systems, gauges should NOT be hooked up to a ductless or VRF system unless they are absolutely necessary. Gauges may introduce contaminants into the system, and they may cause more harm than good if techs use them when they are unnecessary. Superheat is rarely a useful diagnostic reading for mini-split and multizone systems. However, superheat and subcooling are readily available readings that may be useful for diagnosing VRF systems.

Diagnostic work requires detective work; ask questions about the system history to see how it has performed in the past. Involving owners in the repair process is a good way to build a relationship while understanding the problem better.

Like split systems, dirty coils and air filters can severely compromise a VRF/ductless system's performance. So, try to make sure filters and coils are all clean during diagnosis. The fins of evaporator coils can get especially dirty and should be cleaned. Some ductless systems can be cleaned in place.

Be sure to take down the model and serial numbers of the system. If you need tech support, you MUST have those numbers to be as specific as possible. Service and installation manuals are also useful tools for diagnosis (yes, we know that some techs are allergic to reading). However, don't over-rely on the error codes.

Resources

Computer Room Application Formula

Ductless Steps

Friedrich Service Form

Seven Common Install Answers

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Watch the sequel to this podcast episode HERE.

Bonus - Tech Communication and "PM Specials" w/ Frank Besednjak Sep 07, 2017

Frank Besednjak talks about proper communication in conflicts between techs and managers. He also covers the potential problem with inexpensive air conditioning maintenance specials.

When it comes to communication, Frank is a proponent of honesty and straightforwardness. However, he understands and appreciates the fact that people have different communication styles. He encourages people to write down their ideas, whether those ideas benefit the company, themselves, customers, etc. Frank encourages managers to set up an email or text line for people to input their ideas via written media; the leaders should make employees feel empowered to become part of the solution. The difference between a committed and complaining employee will become clear in the way that they communicate suggestions.

Cultivating positivity in the business starts with future-oriented leaders. Managers who focus on the past allow negativity to breed, especially when they fixate on poor performances in the past. Frank also suggests that managers take the "good in public, bad in private" approach when discussing employee performance. The point is to find solutions, not make employees feel bad.

Some PM "specials" include the infamous $89-tune-up. Some techs use these PMs as opportunities to push products and make sales. Frank believes that the pricing is not the issue; dishonesty about the tune-up's intentions is the issue. Sadly, these "specials" are often scams, but they still work for bringing in business. Some companies even do "classes" that are truly sales meetings; those meetings teach techs how to upsell and push products. This practice also opens the door for honest, skilled techs to be replaced with salespeople who do not fix units as they should. Frank recommends implementing a good pricing strategy that lets customers make their own decisions. Then, you will attract business honestly.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

The Basic Refrigeration Circuit, Pressure & Enthalpy w/ Carter Stanfield Sep 04, 2017

Carter Stanfield, a co-author of Fundamentals of HVACR, talks about the entire refrigeration circuit. He also explains how to read and plot a pressure-enthalpy diagram.

The refrigeration circuit has four main components: evaporator, compressor, condenser, and metering device. When teaching, Carter likes to explain that boiling is a cooling process and condensation is a heating process. He describes saturation as the breaking point at which liquid refrigerant can no longer hold more heat (in the evaporator). The superheated vapor from the suction line then enters the compressor; the compressor adds even more superheat. So, the discharge line has very superheated vapor. In the condenser, saturation occurs when the vapor cools to the point that it can no longer hold more moisture; the temperature stays the same until the refrigerant becomes entirely liquid. Subcooled liquid travels to the metering device via the liquid line. The metering device reduces the pressure of the refrigerant and feeds the evaporator. However, some flash gas occurs and helps drop the temperature of the remaining liquid.

A pressure-enthalpy diagram illustrates the refrigerant's changes in and out of the saturated state as it moves through the refrigeration circuit. The chart looks like a curved dome, and saturated states are inside the dome. Pressure is on the y-axis, and enthalpy is on the x-axis. Pressure is a logarithmic arrangement; a linear arrangement would be impossible to plot. The bottom of the chart shows low pressures, and the top shows high ones. Enthalpy is the heat content of the refrigerant. We express it in BTUs/lb.

When you plot one of these diagrams, you can start with four lines and readings: high and low-side pressure, suction line temperature into the compressor, and liquid line temperature into the metering device. You will end up drawing a parallelogram shape on the chart.

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Bonus - Leak Sealants and How They Work w/ James Bowman Sep 01, 2017

James Bowman talks to Bryan about leak sealant products, including RectorSeal's Leak Freeze product. James talks about how sealants work, what happens when they don't work, and how to be open-minded without being gullible.

Leak sealants must not react adversely with the components inside a system (oil and refrigerant). Just as mineral oil caused some issues with O-rings, POE oil has additives that cause acid to form on the system. RectorSeal's Leak Freeze is technically an oil that can work with the oil and refrigerant that already exists in an HVAC system. Leak Freeze is a high-performance lubricant that creates a soft bond around a leak and doesn't clog the system.

Many refrigerant-based polymer leak sealants are hard chemicals that technically succeed at sealing leaks. However, these leak sealants are prone to clogging a system when they clot together (via flocculation). If a sealant has hazard pictograms, then there's a good chance it is a refrigerant-based sealant that creates polymers.

When selecting a product, there will always be pros and cons with each product category. There are cases where each type makes sense; you must know your customers, business, and employees to determine the best choice for each unique situation.

In a test that Bryan performed with Leak Freeze on a rubout leak on the high side of the system, he noticed that the sealant managed to stop the leak while the system ran. Then, the system shut off. After that, there was only a slight leak. Generally, the product was meant to work better on formicary corrosion on the low side, but it still proved to be effective at sealing a leak in a challenging location.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Commercial Refrigeration for A/C Techs w/ Dick Wirz Aug 28, 2017

Dick Wirz, author of Commercial Refrigeration for Air Conditioning Technicians, talks about making the switch from A/C to refrigeration.

Dick Wirz is an advocate for using rules of thumb, which is a controversial position. However, rules of thumb are an excellent way for A/C techs to dip their toes into the refrigeration world. Rules of thumb are less likely to overwhelm technicians than the exact technicalities of certain readings and measurements.

Some prime examples of using rules of thumb in air conditioning are condenser split, evaporator split/TD, subcooling, and superheat. Those all have relatively neat "rules of thumb" that don't vary too much. (30-degree condenser split, 35-degree evaporator TD, 10-degree subcooling, and 10-degree superheat.) On medium-temperature refrigerators, a common rule of thumb is a 10-degree TD for a 35-degree box with an evaporator running at 25 degrees (35 - 10 = 25). On low-temperature applications, the box temperature is -10 degrees. You still have the 10-degree TD, so the design conditions for the evaporator would be -20 degrees (-10 - 10 = -20). The pressures will vary across refrigerants, but the temperatures WILL REMAIN the same as the rule of thumb.

Ice is an alarming sight for residential technicians. However, commercial refrigeration technicians will occasionally see frost or ice under perfectly normal circumstances. Frost merely indicates that the temperature of a pipe is below freezing. Ice alone does NOT indicate floodback. In commercial refrigeration, the fans run all of the time to defrost the system (even during the off cycle). However, in freezers (low-temperature refrigerators), hot gas or electric defrost is required.

Dick also talks about:

Subcooling vs superheat in diagnosis
R-410a pressure confusion
Reach-in and walk-in refrigerators
Medium and low-temperature refrigerators
Defrost controls
Common issues in commercial refrigeration

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Introduction to Ammonia Chillers w/ Camron Conlee Aug 23, 2017

Camron Conlee joins the podcast to give us an introduction to ammonia chillers. He also explains what it's like to work with a poisonous refrigerant. The California division of TDI Refrigeration, where Camron works, primarily works on ammonia systems. We often see ammonia refrigeration in cold storage and food processing; ammonia refrigeration is usually in industrial applications away from the public.

Ammonia is more hazardous than CO2 and other refrigerants because it is toxic. When working on ammonia chillers, the most important thing is to keep the ammonia inside the pipes. You may even need to wear full-face respirators and personal monitors when working on potentially leaky ammonia systems.

Ammonia chiller oil systems are a bit different from R-22 systems. Oil separation is important in both ammonia and R-22 refrigeration, as ammonia systems typically use coalescing separation methods to isolate oil from the refrigerant. However, the oil generally doesn't mix with ammonia as readily in the first place. Some systems rely on pressure differentials to move liquid, and others use pumps to move liquid ammonia into the evaporator.

Preventive maintenance on ammonia systems is quite similar to PMs on other types of refrigeration systems. Compressors are also important components that require occasional maintenance. Like many other commercial refrigeration systems, several ammonia chillers have hot gas defrost.

The ammonia refrigeration world has a few different types of job opportunities. Some companies require in-house operators, but there are also external service companies, which may have a few smaller customers. In almost all cases, these jobs require technicians who can stay calm in crisis situations, as there is a lot at stake.

Camron and Bryan also discuss:

Recirculated vs. gravity-fed systems
High vs. low-pressure receivers
Dry vs. wet suction
Screw compressors
Copper and brass leaks
Finding ammonia refrigeration companies and trade schools

Find out more about TDI at tdirefrigeration.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Scales - The Episode You've been Weighting For w/ Adolfo Wurts Aug 22, 2017

Adolfo Wurts from Arbiter Incorporated, designer of the UEI WRS line of Bluetooth scales, comes on the podcast. We talk all about scales and how to use them.

You'll want to pull a scale off your truck every time you add refrigerant to a system. Many technicians choose to estimate how much refrigerant they have to put in, and they sometimes put in more refrigerant than they estimated in their quote. Consequently, the business loses money. You'll also want to weigh your tanks during EVERY recovery to ensure that you do not overfill your recovery tanks and risk hydrostatic pressure buildup. Weighing the charge also helps keep track of amounts of increasingly uncommon and expensive refrigerants, such as R-22. Also, make sure your scales have good batteries at all times!

Weighing the charge also shows you where previous technicians may have overcharged or undercharged the system to rectify a different issue. For example, someone may have starved their unit to reduce head pressure (maybe the condenser coil caused the high head pressure all along).

To get the most accurate measurements possible, you must assess the quality of your scale and how you use the scale. For example, your scale must be on hard, level ground. (Do not use scales on grass; opt for concrete instead.) You should also center the tank you are weighing. However, the UEI series typically shows little variation under undesirable circumstances. (That is still not a reason to be careless with your scale.)

UEI WRS scales are rugged and excellent for brutal fieldwork and inclement weather conditions. The scales also connect to smartphones via Bluetooth so that you can view the measurements remotely. The WRS series also has a wide range of design features for ease of use.

You can find these scales for sale at TruTech Tools by going HERE.

And don't forget to use the coupon code "getschooled" for a discount at Trutechtools.com.

Find out more about the WRS line by visiting the UEI website.

Big Announcement - 8/21/17 Aug 21, 2017

In this quick announcement I talk about the launch of the revolutionary diagnostic and data management tool MeasureQuick

Looking past the First Thing & Facial (Hair) Profiling w/ Todd Liles Aug 18, 2017

Todd Liles of Service Excellence Training joins the podcast. He talks about techs who shouldn't be on commission, how to make the most of your career, and facial hair profiling.

Todd's skillset was mixed; he had some technical knowledge, sales experience, and communication skills. He took those skills into training, and he started his own business based on his skills; his first business didn't pan out, but he founded Service Excellence Training and has grown quite a bit. Todd develops technicians by teaching them best practices, which also boosts sales.

In the past, some technicians have judged Todd because of his sales background; technicians and salespeople may have negative views of each other due to bad experiences with them. If we want technicians and salespeople to improve their lives, we need to be able to listen to each other and set aside our biases.

Some technicians may resent performance-based pay and argue that it gives sales techs a motive to take advantage of others. The truth is that most of us are simply hardworking people who want to do the right thing for customers. Working for performance-based pay doesn't suddenly make them unethical. In any case, techs can maximize their value by doing best practices and benchmarking the system; collecting data will make a technician more effective and more invested in the client's system and overall best interest.

When it comes to sales, facial hair profiling is very common. The clean-shaven look is a staple of sales technicians, but the training is much more important for sales success.

Todd and Bryan also discuss:

Service Excellence Training core truths of service
Having a rough childhood and making good vs. bad choices
Flat-rate vs. performance-based pay
Disorganized technicians and where they might shine
Dealing with paperwork
Uneducated technicians vs. shysters
Facial hair policies

Learn more about Todd's work at servextra.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Advanced Evacuation w/ Jim Bergmann Aug 16, 2017

Jim Bergmann returns to the HVAC School podcast to cover some advanced topics in evacuation, including rig setups and triple evacuation.

To increase the speed of evacuation, you need two large-diameter vacuum hoses to overcome the limitations of pressure. Core removal is also critical, as Schrader cores are a significant restriction. It's also unwise to use a manifold for evacuation; a manifold will double your hose length, provide a restriction, and serve as a leak point.

The vacuum pump is full of opportunities to expand your advanced evacuation knowledge. The pump oil needs to stay clean, and Jim recommends changing the oil after every use. When it comes to pulling the vacuum, it's worth noting that the vacuum is deeper at the pump than at the system itself. The vacuum at the pump does NOT reflect the vacuum at the system; core tools can isolate the vacuum pump from the system so that you can measure the true vacuum at the system.

When we "break" with nitrogen, we're referring to nitrogen sweeps at different stages of evacuation (especially in the case of a triple evacuation). Triple evacuations are rarely necessary nowadays, but you may need to break with nitrogen from time to time. Nitrogen moves through the system so quickly that breaking with nitrogen often has a minimal impact on the vacuum.

The length of evacuation doesn't really affect dehydration until you get below about 300 microns. Dehydration has more to do with the strength of the vacuum than its length.

Jim and Bryan also discuss:

Locking refrigerant caps
Assembly lubricants
Outgassing odors and gas permeability
Hygroscopic vs. hydrophobic vacuum pump oil
Vacuum pump oil management
Average air conditioning decay rate
Thermistor vacuum gauges
Nitrogen regulators
Metering devices
Gas ballast on vacuum pumps

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Using ZoomLock Every Day w/ Brent Ridley Aug 10, 2017

In this episode, Brent Ridley talks about the flame-free ZoomLock fittings and why he is using them for almost everything to replace brazing. These are tools from Parker, and they can give you leak-free fittings within seconds.

ZoomLock works in residential and commercial applications. The fittings come in a wide range of sizes for the large piping of VRF systems and the smaller copper tubing of residential A/C suction lines. Brent measures the tubing to make sure there's enough room. Then, he cuts the bell end off, deburrs the copper, sands the copper down, and applies the fitting. You do NOT have to apply a lubricant or anything before you add the fitting. The fittings have two grooves to match the grooves on the jaw; that is how the fitting can crimp properly.

Brent likes ZoomLock for its time-saving potential. You don't have to get your oxyacetylene (or air-acetylene) rig prepared and spend time brazing. There is also the potential to save money on the fuel and nitrogen you would use while brazing. As technology improves and the price goes down with increased production, it's possible that we can see ZoomLock-type fittings in more applications.

Brazing is a key skill, but it also comes with a lot of risk to our bodies and customer property, so ZoomLock is a promising replacement for brazing. Will ZoomLock replace brazing altogether? Probably not; it would be quite difficult to use those fittings on a reversing valve, for example. But is ZoomLock a nice tool to consider for some applications? I think so.

Brent and Bryan also discuss:

How Brent was introduced to ZoomLock
Stub lengths
Oil compatibility (POE vs. mineral oil vs. refrigerant)
Lateral strain on fittings
Filter-driers

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

How to Perform a Leak Detection on a Low Pressure Chiller w/ Jeff Neiman Aug 09, 2017

Jeff Neiman returns to the HVAC School podcast to explain how we can perform leak detection on a low-pressure chiller. Jeff works on systems with glycol loops or other forms of secondary fluids, which may have leaks from time to time. When the chilled water pump on the suction side runs into a vacuum, air can get into the system via the shaft seal. Then, more leaks can occur in the glycol loop as more air goes into the system.

High-pressure chiller leak detection is pretty much the same as on a package unit. However, your typical low-pressure chiller will sit in a vacuum and require us to spend more time on leak detection. These low-pressure systems often have massive amounts of refrigerant below atmospheric pressure. These may have purge units that keep non-condensibles out, but some trace amounts of refrigerant can be vented out with the non-condensibles. Leaks on the low side of the system can cause even more refrigerant venting.

Leak detection on the condenser side of a low-pressure chiller is pretty straightforward; like high-pressure chillers, you can use the same leak detection methods you'd usually use on a package unit or split residential system. When you know you have a leak on the low side, you can turn the chiller off; it will still be below atmospheric pressure, so you'll need to bring up the pressure to find a leak. Otherwise, you can weigh out the charge and flow nitrogen with trace amounts of refrigerant through the system.

Overall, leak detection can take a LONG time on low-pressure chillers.

Jeff and Bryan also discuss:

High vs. low-pressure centrifugal chillers
Raising the pressure on the low side
Submerging leaky components in water
Leaking in the tubes
Pressure and its effects on gaskets
Jeff's leak detection tools
Open-drive motors

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Special Episode - The Launch of an HVAC Industry Changing App w/ Jim Bergmann Aug 04, 2017

In this episode of the podcast, Jim Bergmann talks about the launch date of the measureQuick (MQ) app, what it will do, why he made it, who it is for, and why it's different than anything else that came before.

MeasureQuick is a universal measurement platform that incorporates Bluetooth to display, store, and interpret measurements. The initial release focuses heavily on air conditioning, but its goal is to assist with combustion analysis and refrigeration readings. It is a troubleshooting assistant that saves time and helps technicians make sense of their readings. It combines the air side, refrigerant side, and electrical side in a single Bluetooth-connected technology.

MeasureQuick helps technicians understand if the conditions are ideal for testing or if the system performs optimally while testing. The app does not automate the diagnostic process, but it is a diagnostic aid to help reduce callbacks. MeasureQuick contains both free and paid components for users, and it is backed by Testo and other sponsors.

Jim Bergmann's app brings a technological appeal to the tech-savvy rising generation. MeasureQuick encourages curious technicians to understand their readings and diagnostic criteria. The goal is to modernize the HVAC industry while bringing the knowledge base of the older generation to the newer generation. Jim Bergmann's goal is to make the app TEACH its users the best practices and principles of the industry; he aims to make information accessible to technicians with varied learning preferences. This app is especially useful for those who are not avid readers.

Of course, hacks who don't care about learning the correct way will always exist. However, MeasureQuick will hopefully bring accountability to our industry through education.

You can find out more by going HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Condensate Switch Codes and Practices w/ James Bowman Aug 02, 2017

James Bowman of Rectorseal returns to the podcast to discuss condensate switch codes and some best practices to comply with the codes.

The humble condensate switch actually has installation standards; although there isn't a "law" about the codes, many areas follow and enforce the contents of the International Mechanical Code (IMC). Some states, including Florida, also adopt elements of the IMC and amend it to create a set of guidelines for the state.

The IMC has widely-enforced code 307.2.3.1, which states that water-level monitoring devices must be installed in the primary drain pan; the device shall shut off the equipment. This code applies to downflow units and all other coils that don't have a secondary drain pan or provisions to install an auxiliary drain pan. The code also states that devices installed in the drain line are not permitted. However, code 307 is actually NOT saying that you can't install a switch in the secondary port at all; there are four different ways to comply with the code without installing a condensate switch in the primary drain pan.

Switches must comply with UL 508. However, there are plenty of non-compliant switches on the market. These may even say that they "conform" to UL 508. Compliant switches will generally not short out when dropped in water, but it's up to us to make sure we're using code-compliant switches.

If you're installing a float switch, be sure to follow the instructions; that's usually the best way to comply with local codes and protect the equipment. As always, make sure you test the switch before you leave the job site.

James and Bryan also discuss:

Mini-split drain considerations
Float switches in the primary drain line
Piping auxiliary floats
Testing safety switches for heating equipment
Drain pitch
Rectorseal condensate switches
Keeping redundancy in mind
Condensate switches for RTU and ductless units

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bonus - Being On Call w/ Les Fork Jul 31, 2017

Les Fork returns to the podcast to discuss on-call rotations. He explains why being on call is necessary and how you can make the most of it.

We are supposed to be on call for the sake of customer service; when a customer has an emergency, it's best for the customer (and the business) when someone is available to respond to the emergency. Of course, many of us dread being on call (although the paycheck might be quite nice).

You may only have one or a few techs on call, so it can be difficult to take on all of the customers each day. Although it's generally okay to speed up a bit and be less thorough, you should still be working to fix the issue at hand and tell the customer if the system needs further inspection in the future; it's also a great opportunity to propose a maintenance plan. The system should be working, the compressor should be running, and the capacitor should not be over-amping.

Some companies may offer 24-hour service, and others may not. If your company offers 24-hour service, you may indeed be on call at all hours of the day and night. It makes more sense to offer 24-hour service to commercial customers, though you can certainly offer it to a residential market. Overall, it might not be best to advertise 24-hour service because you may draw in price shoppers. (You're also at liberty NOT to offer service after hours.)

Les and Bryan also discuss:

Managing anger and being professional
Empathy
Billable vs. non-billable hours
Order of inspection
Scheduling and prioritizing customers
Walking customers through frozen coils
Money talk: warranties and call-out fees
Cleaning drains
Tip ethics and etiquette
Collecting payment

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Measuring Air Flow - Air Density and Direct Air Flow Measurement Part 2 w/ Jim Bergmann Jul 24, 2017

In this podcast episode, Jim Bergmann continues talking about standard air, air density, and mass vs. volume as well as some other methods of "directly" measuring airflow. It gets pretty deep.

Airflow hoods and vane anemometers can give you direct airflow measurements.

You use static pressure probes, not pitot tubes, to measure TESP. When measuring static pressure, you put the negative probe in the return and the positive probe in the supply. Then, you measure the TESP (away from wiring and airflow). However, air pressure fluctuates as that air moves in the duct. Velocity pressure occurs when air moves and creates turbulence. The blower moves air, which has weight. As such, density, volume, and mass are all important as well. As air density changes, the CFM remains constant at a variable mass flow rate.

When it comes to using any tool for measuring airflow, static pressure, etc., all tools are an investment of money and time; you must spend some time learning how to use those tools. You will discover those tools' limitations and must learn how to work with or around those limitations.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bonus - Impressions From a Week as a Tech from a College Intern w/ Bill Spohn Jr. Jul 24, 2017

Bill Spohn Jr. is a college intern working towards his business degree, but he took a week to see what it is like to work as an HVAC tech. He shares his impressions on this podcast. Bill is the son of Bill Spohn and has been a college intern working with TruTech Tools. However, he has just gotten his first real dose of the HVAC contractor experience in the full swing of summer.

Bill started off by riding with a Kalos residential tech, Tyler, who had seven calls that day, mostly for PMs; they worked from 8:15 to 9:00 PM. Bill was impressed with the professionalism of Tyler and how well he communicated with customers. The second day, Bill got to do an install, which was a physically taxing task (partially due to the Florida heat). He put in a new drain pipe, new copper tubing, a new air handler, and some new pieces of ductwork. Bill also spent a day with Jeff, where he did a lot of preventive maintenance.

As with many people, Bill learned a lot about the importance of refrigerant and proper charge. He also found SEER ratings and other efficiency measures fascinating.

Bill went into his experience with the idea to identify "pain points" for techs and suggest improvements to current tools and technology. Now that Bill knows what's important to techs in the industry, he can bring ideas to TruTech Tools to make the techs' lives easier and address the "pain points" that many contractors have to deal with.

Bill and Bryan also discuss:

Tyler's past
Working on trailers or mobile homes
Organization (or lack thereof) in vans and tool bags
Combined analog and digital gauges
Inventory tracking systems
Possible Testo 115i temperature clamp improvements

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Measuring Air Flow - Static / Capacity & ECM Motors Part 1 w/ Jim Bergmann Jul 19, 2017

In this two-part podcast series, Jim Bergmann talks about measuring airflow in HVAC systems. He covers a wide range of airflow measurement instrumentation and readings.

In this first episode, Jim covers ECM motor considerations, delivered capacity, laminar flow, and more.

In the HVAC industry, many techs confuse static pressure for airflow. Although you need static pressure to have airflow, it is NOT airflow and can fluctuate rather wildly depending on the duct conditions.

Static pressure is an indirect airflow measurement. Airflow is actually a measurement of velocity (such as with pitot tubes) that you then convert to a volume measurement (CFM).

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Brazing Basics and Tips Jul 12, 2017

In this podcast episode, Bryan talks about brazing basics and tips. He goes over safety, regulator settings, torch positioning, flowing nitrogen, heat control, and more.

Whenever you're going to be working with equipment that creates fire, you will want to make sure you know all of the safety procedures and have appropriate PPE. Make sure your gear is in really good condition; make sure your hoses and regulator have not been damaged. Be sure to have a fire extinguisher handy as well. When preparing copper lines, you'll want to keep things out of them. Make sure oxygen, dust, burrs, and flux can't get into the tubing.

Flowing nitrogen is a best practice, but it's also a staple among the brazing basics. Nitrogen displaces refrigerant, water, and oxygen that might be in the copper lines. Regulators can help you purge with nitrogen at somewhat higher SCFH (20-50) and then flow it at a very low SCFH (2-5). You should hear just a whisper of nitrogen when flowing it.

When you set up your torches, it's important that you look at the torch manufacturer's specifications. The tips have different designs for different functions, and it would be wise to read up on their purposes. When setting the oxygen and acetylene pressures, try to keep the numbers the same. Light acetylene first and THEN add the oxygen, and then you'll want to turn off the oxygen first and then acetylene. You'll want a neutral or slightly carburizing flame but not an oxidizing flame.

Bryan also covers:

Protecting the workspace
Unsweating
Reaming copper
Reducers, fittings, and swaging tools
Nitrogen flow regulator types
Wrenches for opening tanks
Brazing vs. soldering
Brazing/soldering rods
Getting the copper hot enough
Preventing carbon buildup
Leak testing joints

Bonus - Blue Collar Life & Experience w/ Ralph Wolf Jul 10, 2017

Bryan talks to Ralph Wolf from T&N Services on YouTube and the Working Joe's podcast. We talk about blue-collar life, how the trade has changed for us, and what experience gives a tech that can't be read in a book. Ralph started off doing sheet metal work in the Navy before going into HVAC. He started as a sheet metal installer and learned most of what he knows about HVAC on the job.

Taking accurate superheat and subcooling readings have become much more important over the years. We can't get away with "beer-can cold" rules of thumb anymore, especially as MicroChannel and TXVs have evolved and become more prevalent. Efficiency is becoming more important as well, especially due to government mandates.

Blue-collar jobs have a ton of best practices for each trade. However, those who have been in the trade a long time typically know the appropriate times and places for those practices. (For example, you don't need to check static pressure on EVERY system, but it's a great idea when you're commissioning a system or working on a system with airflow issues.) As you gain experience, you'll know when to use best practices and when you can bypass them for the sake of time. So, you'll come across two types of senior techs in the trade: those who are plain lazy and those who simply know the exact times and places for best practices.

Even though the blue-collar lifestyle very much becomes a part of who we are, we each have a different relationship with the trade.

Ralph and Bryan also discuss:

The practicality of best practices
Corrosion
System longevity
Airflow problems
Understanding individual pieces of equipment
Carbon buildup
Leak sealants
Ralph's YouTube journey
Differences between old-school tradesmen and millennials
Calling out dishonesty and poor quality

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Drying Stuff vs. Drying Air - Humidification, Dehumidification and Ventilation Jul 03, 2017

This episode is a rebroadcast of a very useful episode from the Corbett Lunsford's Building Performance Podcast at https://buildingperformancepodcast.com/. Corbett talks to building moisture control expert Lew Herriman about moisture, ventilation, and what happens when you're drying "stuff."

When we think about humidity control, we have to ask if we're drying air or drying "stuff." Dehumidification is about drying the air, but many people think about it when they actually want to dry "stuff" like fabrics and other absorptive surfaces often found in residential applications. However, drying out "stuff" does affect how we would dry out the air.

Commercial buildings often don't have a lot of absorptive materials, as many have tile floors. Residences tend to have carpet and upholstery, making them challenging cases in building performance. The HVAC system controls moisture, whether they have a humidifier, dehumidifier, or neither. HVAC systems create pressure differences, which contribute to dry air infiltration. Homes heated solely by radiant heat would not be as good at drying the air, but good ventilation could supplement radiant heat.

When we have humidity control problems that affect comfort or moisture on absorptive surfaces, we might start thinking about controlling absolute humidity. Absolute humidity refers to the actual moisture content in the air, not the moisture relative to the temperature. However, most homes don't have the ventilation systems that would help dilute the humidity, including HRVs.

Then, when drying "stuff," you have to put heat in to get the moisture out.

Corbett and Lew also discuss:

Absolute vs. relative humidity
Dry-bulb temperature changes and dew point
Duct leakage
HVAC and building performance strategies for mixed climates
Energy-recovery ventilators (ERVs) vs. heat-recovery ventilators (HRVs)
Exhaust at the source
Dehumidifiers
Dehumidifying incoming fresh air
Hypothetical makeup air systems for residential applications
Comfort metrics

Learn more about Corbett's work at buildingperformanceworkshop.com.

Bonus - Restaurant Equipment "Hot Side" w/ Nick Messick Jun 30, 2017

Restaurant HVAC and refrigeration tech Nick Messick comes on the podcast to talk about restaurant equipment, especially the "hot side." The "hot side" refers to equipment that heats the food; it includes often deep fryers but has a lot of variation. The "hot side" also includes specialty equipment for frying noodles and performing other unique functions.

In Nick's opinion, the worst service call has to do with fryer pumps due to all of the grease. The grease gets all over tools and your hands, and it can be quite difficult to work on equipment with fryer grease. Other things he dislikes working on are machines that are on their last legs, as many owners are reluctant to replace equipment.

Many fryers go through a melt cycle that turns the heat on and off to avoid burning the oil. The flames heat the bottom of the vat using a heat exchanger like a furnace; then, the gas vents into the flue and out the hood. These systems generally use spark igniters and may use either direct-spark or intermittent-spark ignition with a pilot. Nick's favorite call is when fryers make loud popping noises, as it's easy to diagnose and fix; the cause is typically either the ice cube relay or a bad igniter.

In grease-heavy restaurant environments, we clean equipment by using cleaners meant for electrical equipment. You want to avoid leaving residue on the equipment and ruining the control boards. The restaurant staff should be cleaning out the fryers themselves, but you may encounter some dirty equipment (and workspaces).

Nick and Bryan also discuss:

Dishwashers
Replacing equipment
Flame rectification
Circuit boards
Electric fryers
Drawing the line when it comes to sanitation in HVAC service

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

P.S. - Don't pull the fire alarm

Building Automation Basics for the HVAC Tech w/ Phil Zito Jun 28, 2017

Phil Zito of Building Automation Monthly comes on the podcast to discuss building automation and what HVAC techs should know about it.

Automation essentially refers to control systems; we started off with pneumatic control systems, and then we went to analog and electromechanical control systems over time. Building automation refers to the process of automating controls on a larger scale, such as for an entire building. As long as you can read electrical and mechanical diagrams, you can work on automation systems; you don't need to know about IT or robotics.

Large buildings like malls may require HVAC automation. In other structures like university buildings, you may also end up automating lights and other electrical functions. Automation makes other systems talk to each other, and it does that by controlling on/off schedules and set points. These building automation systems consist of sensors, switches, conductors, and decision-making logic (such as simple desktop servers).

Regardless of the automation system, the sequence of operation will always go in the following order: server, supervisory device, field controller, and input/output. A communication bus transmits messages between field controllers; it works like floating controls or pulse-width modulation. You don't need to know the binary communication of the computer; you just need to know how to measure voltage with your multimeter to work on a communication bus.

An HVAC tech may also be interested in knowing that building automation has an air side and a water side. These systems may also interface with package RTUs and VAV systems.

Phil and Bryan also discuss:

How Phil got into building automation
Servers
User and web interface
Resistance vs. analog values
Barriers to getting into BAS careers
Installation vs. service
Taking initiative and being resourceful
How BAS and HVAC workers can make each other's lives easier

Visit Phil's website HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bonus - HVAC Contractors and Distributors, Keys to a Great Partnership Jun 23, 2017

In this podcast episode, Bryan and Mike Layton of Shore Distributors explain how HVAC contractors and distributors can build a great partnership. Shore Distributors is a wholesaler in Maryland that carries Carrier, Bryant, and Payne.

The job of a territory manager is to help HVAC contractors, so they're there to help contractors. The territory manager's job is to help set contractors and dealers up for success, so they don't feel burdened by questions because it's their job to answer them. Territory managers know that the goal of business is to make money, so they understand the importance of moving boxes and making sales. That said, contractors who move boxes tend to make the rules and have access to privileges.

Warranty returns are a bit of a touchy subject; distributors tend to give contractors the benefit of the doubt and are generally willing to replace the part as long as you supply the correct information. However, Mike believes that the 10-year parts warranty has been detrimental to business.

End-user satisfaction is a goal we can all strive for. HVAC contractors can be more thorough when completing their jobs and setting up equipment; when installers take their time and explain proper use to the owner, they increase customer satisfaction. When HVAC contractors succeed, distributors succeed and can keep providing service to top contractors.

Overall, a healthy contractor-distributor relationship has mutual trust built on dependability. Distributors need to be dependable and available to help the contractors they serve.

Mike and Bryan also discuss:

A day in the life of a distribution role
Ego vs. results
Contractors that abuse warranties
Vetting techs and holding them accountable
Controls
What installers can do better
Inverter products
Understanding each other

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

TXV Operation, Diagnosis and Failure w/ Jamie Kitchen Jun 20, 2017

In this episode, Bryan talks with Jamie Kitchen from Danfoss about why and how thermostatic expansion valves (TXVs) fail and how they function in the first place.

As fixed orifices become a dying breed with the development of higher-efficiency systems, TXVs take over the mantle as the primary method of expansion. Expansion valves meter the flow of refrigerant by aiming for a certain suction line superheat value. Unlike a fixed orifice, which has an opening of a constant diameter, an expansion valve adjusts the opening size to the evaporator based on suction superheat readings.

TXVs have a sensing bulb, diaphragm, spring, and cap tubes. Various pressures act on these components: bulb pressure, spring pressure, and evaporator pressure. The sensing bulb picks up the suction superheat adjusts its pressure on the diaphragm based on the superheat it detects. Spring pressure and evaporator pressure act against the bulb pressure. The combination of all three pressures (bulb vs. spring + evaporator) dictates the opening of the TXV orifice into the evaporator. The bulb pressure is an opening force, and the spring and evaporator pressures are closing forces.

You can cause TXV failure by adjusting it or brazing it in improperly. When too much heat is applied to the TXV, the components inside can warp. Some TXV failures also occur due to contamination. Flowing nitrogen while brazing flushes carbon and oxygen contaminants out and reduces your risk of TXV failure later on.

Bryan and Jamie also talk about:

TXV anatomy (powerhead, spring, etc.)
Internal vs. external equalization
Pressure drop across the distributor
Subcooling and its relationship with the TXV
Solenoid and ball valve (upstream) malfunctions
Filter-dryer placement
TXV assessment during commissioning
Locating restrictions
Residential system airflow

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check The Charge Without Connecting Gauges - Part 2 Jun 14, 2017

In this second part of the podcast, Jim Bergmann wraps up the steps to check a system charge without connecting a gauge manifold.

You can check the charge without gauges if you use the following process (and know your DTD, CTOA, etc.):

Take the dry-bulb temperature. (Let's say it's 70°F in this example.)
Subtract the DTD (35°F).
Add target superheat (10°F).
Check the suction line. It should be 45°F in this example. If your probe senses a temperature that is NOT within 5°F of the temperature you calculated, check the filter, evaporator coil, etc., for dirt.
If the system is not dirty, check the charge with gauges.

For a more extensive look at the process in writing, check out THIS article.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check The Charge Without Connecting Gauges - Part 1 Jun 13, 2017

In this episode of the podcast, we talk about gauges. Jim Bergmann from Redfish Instruments and the MeasureQuick app explains why you may want to check a charge without using a gauge manifold. (That's not clickbait; if you've already connected gauges to a unit once, you can probably check the charge of that unit WITHOUT gauges moving forward.)

HVAC units manipulate temperature and pressure in the refrigerant charge. Heat transfer occurs between the refrigerant and the environment, and various readings indicate the charge level WITHOUT necessarily connecting the gauges. So, you can check the charge if you know the unit's SEER rating, target superheat, DTD, CTOA, and if the unit uses a fixed orifice or TXV.

A large portion of checking the charge without gauges deals with "benchmarking" the equipment. You do that by evaluating the system's performance over time and comparing it to the performance when the system was first commissioned. Airflow WILL decrease over time due to components becoming dirty.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Common Duct Design Mistakes w/ Jack Rise Jun 06, 2017

In this episode, Jack Rise talks about duct design regarding ACCA manual D, friction rate, face velocity, duct velocity, and what is ACTUALLY wrong with flex duct.

Manual D causes a lot of confusion for technicians, and most techs have a limited understanding of it anyway. When determining a blower wheel for commercial ductwork, Jack Rise calculates pressure drops for all of his elbows in the ductwork and makes his decision based on those calculations. Residential HVAC is a bit trickier, and that's where Manual D calculations come in. Luckily, many software nowadays, including Wrightsoft, can calculate loads very precisely and help you with duct sizing.

Just as with heat and pressure, there must be a velocity differential if you want air to move. If you need to move more BTUs of heat, then you need to move more CFM of air. Air also tends to take the path of least resistance. Trunk and branch design velocities must be different if you want any control over where the air goes. Trunk duct velocity typically stays between 700-900 CFM, but branch velocity can change quite a bit when you change the locations of the registers and grilles. Branch velocity tends to be 400-600 CFM. Good face velocity can be achieved by choosing the correct register and putting it in an ideal location.

Flex duct is not a bad material, but it is controversial due to its reputation for being poorly handled. Manual D has an appendix on compression and sag, and techs who consult it will design a much better duct.

Jack also discusses:

Available static
Choosing a blower and factoring friction rate
Oversized ducts
Compression, sag, and bends in flex duct

You can find the book at http://www.acca.org/store

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Why A/C Units Freeze w/ Eric Shidell Jun 02, 2017

In this episode, Bryan speaks with Eric Shidell about some of the basics of system freezing, what causes it, and what to do about it.

Freezing is a normal part of some equipment, such as low-temperature freezers and outdoor units on heat pumps. On straight-cooling systems, freezing is NOT normal and indicates poor operation. Ice formation starts on the evaporator coil and may spread to the compressor via the suction line. The best way to remove ice and defrost the system is to pull the disconnect on the outdoor unit but let the indoor fan keep running. Or, you could turn the unit off but leave the fan on.

The goal is to defrost slowly and steadily. Defrosting too quickly could potentially cause damage. Horizontal air handlers in the attic can flood the home if ice forms and melts off too quickly. In an upflow furnace, defrosted ice could damage the electrical components.

You will typically find low suction pressure on frozen systems. Many technicians who merely attach gauges and don't thoroughly inspect the unit for freezing will mistake the low pressure as a result of a low refrigerant charge. However, low pressures are a SYMPTOM, not the cause of freezing.

Freezing is generally caused by poor airflow over the evaporator coil. As frost appears on the evaporator coil, airflow will be further impeded. On top of that, the suction pressure drops even more. From there, all of these factors feed each other and cause the frost to snowball out of control (almost literally). Sometimes, coils may freeze due to low refrigerant, but the amount of ice will typically be minimal compared to freezing that occurs due to an airflow issue.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Blower Door Testing, Building Performance & More w/ Corbett Lunsford May 30, 2017

Corbett Lunsford from the Building Performance Workshop and the Proof is Possible tour talks to us about the moral superiority of building performance testing, blower door testing, and much more.

Building performance and HVAC have been becoming much more closely linked lately. So, it's a good idea for HVAC techs to learn a bit about building performance.

In the HVAC world, we often see homes with extremely hot upstairs portions and cool downstairs questions. That is a complex building performance issue. A good contractor can troubleshoot the issue with the building and find cost-effective ways to improve the enclosure (air ceiling and insulation) and the HVAC. The construction and improvement industries will be utilizing diagnostics and metrics, much like most of the HVAC industry today. (Metrics that we use include static pressure, superheat, subcool, etc.)

The blower door is the most important tool for diagnosing issues with the enclosure. Many odor and comfort issues deal with ventilation, not just the HVAC. As such, blower door testing can help diagnose issues that don't go away after improving or repairing the HVAC system. Air leakage is the most important issue that occurs with the enclosure.

A blower door test replaces the front door with an airtight shroud with a fan mounted inside. That fan then hooks up to a manometer to measure pressure in the home with reference to the outdoor pressure. The blower door drags the pressure down to 50 pascals, and then you can see how much air goes through the fan at that constant pressure. The air that comes through the fan indicates a lack of airtightness in the home. However, blower door testing requires practice and repetition. If you get one, practice with it before you use it for diagnosis.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Introduction to CO2 w/ Andre Patenaude May 25, 2017

In this episode of the podcast, Bryan talks with Andre Patenaude from Emerson about CO2 refrigeration, and transcritical booster systems. Modern CO2 systems are efficient and effective due to their electrical controls and components, including case and high-pressure controls.

Carbon dioxide (CO2) is a good refrigerant to address global climate change. From a sustainability standpoint, carbon dioxide is a superior refrigerant to HCFCs and HFCs. Carbon dioxide is also an A1 refrigerant, meaning that it is non-toxic and non-flammable. It is also inexpensive and compares to HFCs in cost. Unfortunately, it can rapidly change pressures and is more efficient in lower ambient temperatures. Overall, CO2 is a desirable refrigerant as we address the challenge of sustainability but is not without its challenges.

During the refrigeration cycle, carbon dioxide's critical point comes into play. In hotter ambient temperatures, the carbon dioxide's temperature and pressure may exceed the critical point. The refrigerant then becomes a supercritical fluid; the pressure and temperature change independently of each other. Accessing the supercritical zone is also known as "transcritical."

Carbon dioxide refrigeration is best for low-temperature grocery refrigeration. It has also worked its way into industrial refrigeration.

However, the greatest challenge revolves around the condensing temperature. Carbon dioxide must reject its heat to something that is much colder than it. A transcritical booster system's condenser becomes a gas cooler in the summer; instead of leaving the condenser as a liquid, a CO2 system leaves the gas cooler as a supercritical fluid. It becomes liquid when it passes through an electronic expansion valve (EEV) before the receiver. The CO2 refrigeration system also contains a flash tank and a bypass valve. The bypass valve partially dictates which compressor the refrigerant fluid travels to. There are also low and medium-temperature evaporators and compressors.

Resources

Seven Keys to Servicing CO2 Systems - Article by Andre

CO2 Booster Systems Introduction - Article by Bryan

Cascade Refrigeration - Article by Bryan

Emerson CO2 Application Guide

Bill Spohn is the Man-ometer / 10 Years of TruTech Tools May 23, 2017

In this just-for-fun episode, we celebrate 10 years of great tools and excellent customer service with TruTech CEO Bill Spohn. We hope you enjoy this lighthearted episode with some discussions about company culture, superior service, and a commitment to quality.

TruTech's approach to service goes more beyond selling the tool. The engineers at TruTech aim to learn how technicians plan on using tools. Those engineers want to use their technological expertise to create products that make technicians' lives easier in the realm of diagnosis and measurement. TruTech Tools also works to honor its relationship with the HVAC community and market. The engineers at the company see the value in the relationship between HVAC and building performance. TruTech Tools also carries trusted brands, such as Testo and Carrier.

When it comes to pricing, TruTech Tools believes in pricing based on the market price and backing up the product with superior service. Most of a product's value comes from the seller's service. TruTech Tools also remembers to reward loyal audiences and buyers with discount codes or rewards systems.

Bill Spohn also wants TruTech Tools to develop some more educational materials in the future. The company has a close relationship with the HVAC industry and wants to show its support through a commitment to training.

Overall, TruTech Tools values its connection with the HVAC community and takes pride in its standing as a trusted tool provider for such a great community.

Check out TruTech Tools at trutechtools.com and use the offer code "getschooled."

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Check out our handy calculators HERE.

When Will Techs Be Replaced By Robots? w/ Adolfo Wurts May 22, 2017

In this episode, Bryan talks with HVAC products designer Adolfo Wurts about technology, automation, and the coming robot apocalypse. Automation is a fear in many industries, and the HVAC industry isn't alone. Today, we talk about how instrumentation and AI technology may develop and what that will mean for the future of the industry.

Some recent practices that have severely impacted the job market lately have been globalization (where work moves overseas) and automation (where machines replace human labor). Globalization is not a major threat to our industry due to the local nature of our jobs. However, automation seems like a more valid concern. Automation has been occurring for a long time; it started off by replacing animal labor with vehicles at the beginning of the Industrial Revolution in the 1800s. Machines have also slowly been replacing repetitive human tasks.

Some high-wage professions have already been replaced by technology, including tax preparers and travel agents. That is because those people make high wages, and automation makes sense economically. Conversely, the cost to replace a fry cook with a robot would probably exceed the amount of money it would save in wages.

However, humans use their senses to solve problems; machines cannot make judgments based on sight, smell, sound, etc. HVAC techs use those senses to diagnose issues with the system. So, HVAC techs would be very difficult to replace with robotic technology. The customer service element of HVAC work, especially listening skills, would also be difficult to reproduce in a robot. So, we have lots of assets that technology cannot replace anytime soon.

Bryan and Adolfo also discuss:

Maintenance vs. healing
Datasets, algorithms, and robots
Technicians that will be automated before HVAC techs
Variable vs. standardized technology (homes vs. cars)
The concern of "dumbing down" techs with smarter diagnostic equipment

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EPA 608 Changes - What You Need to Know w/ Jeremy Arling May 17, 2017

In this episode of the podcast, Jeremy Arling from the EPA comes on and answers some common questions about the new rule changes that affect recovery, leak repair, recordkeeping, and evacuation on HVAC and refrigeration systems.

EPA 608 rules regulate the actions that technicians must take when it comes to refrigerants and the atmosphere, such as venting, recovery, and evacuation. It has always been illegal to vent HFCs, including R-410A. The changes to EPA 608 attempt to treat all refrigerants equally; R-410A would be on equal footing with HCFC R-22, for example. EPA 608 also clarifies the actions that require certification, including the purchase of ozone-depleting substances.

It is not illegal to recharge CFC or HCFC refrigerants. However, the availability of HCFC refrigerants will dwindle over time; systems will need to be charged with reclaimed refrigerants, not new R-22.

EPA 608 will also crack down on recordkeeping for recovery and reclamation. The technician does NOT have to keep the records; it is the responsibility of the company. However, the technician should keep track of the recoveries they do and provide those records to their companies.

When recharging leaking systems with over 50 lbs of refrigerant, technicians should know that HCFC-reliant appliances must be repaired, retrofitted, or retired within specific timeframes. There is no minimum time frame between the leak repair and verification testing; however, the EPA recommends testing within 10 days of the repair.

The EPA has approved the use and recovery of flammable refrigerants for a handful of industrial applications. Most of these also receive exemptions from the venting prohibition.

Resources

You can find the complete rule update HERE. You can also find Jeremy's presentation slides HERE and a quick sheet for technicians HERE.

If you want an app to help you keep a record of recovered refrigerant, I would suggest looking at the R-Log app HERE.

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Evacuation 101 w/ Jim Bergmann May 12, 2017

In this episode of the podcast, Jim reviews the basics of evacuation and dehydration. He also covers hoses and vacuum gauge placement.

Evacuation may just seem like a method to suck air and water out of a system. However, it is an intricate science that lacks a lot of detail in most trades education programs. The deepest vacuum we can possibly pull merely offsets the atmospheric pressure and is actually not that deep; the deepest possible vacuum is -14.7 PSI (-29.92" Hg).

The evacuation rig is the most important element of evacuation. If you want a fast evacuation, DO NOT use 1/4" hoses or manifolds. However, those are both common practices in the HVAC industry. The only way to increase the flow of refrigerant, air, and water out of a system is to increase the hose diameter. Larger hoses have less resistance than smaller hoses. Pump size does not seriously impact evacuation speed when compared to hose diameter and the presence/absence of Schrader cores. Schrader cores are other major sources of restriction, and you'll want to use core removal tools.

Air from a vacuum pulls in a localized area. As such, it is a BAD idea to hook your vacuum gauge up at the vacuum pump. You are measuring the pressure of the pump, in that case, NOT the whole system. When you read 500 microns at the pump, the real pressure of the system could be over 1000 microns (especially if you have 1/4" hoses).

Bryan and Jim also discuss:

Atmospheric pressure
Connectors
What is a "good" vacuum?
Decay tests
Moisture throughout the system and its effects on decay
Water's state changes and vacuum
Sublimation and ice during an evacuation
Capping off, soldering, brazing

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Psychrometrics for Fun and Profit w/ Jamie Kitchen May 08, 2017

In this episode of the podcast, Jamie Kitchen from Danfoss talks about wet-bulb, dry-bulb, relative humidity, dew point, enthalpy, and latent heat. These are the building blocks of psychrometrics, which deals with human comfort as it relates to temperature, humidity, and heat loads.

Humidity is water vapor in the air. As the air's dry-bulb temperature increases, the more water vapor the air can hold. That is partially why dew is more common on cold mornings instead of hot ones. However, the air's weight does NOT increase with more water vapor; moist air is less dense than dry air. Moist air has more heat energy than dry air, though. Relative humidity (RH) is the percentage of moisture that the air can hold before saturation. Saturation occurs at 100% RH.

In psychrometrics, there are two different types of relevant temperatures: dry-bulb and wet-bulb. Dry-bulb temperature refers to true thermodynamic temperature; humidity doesn't affect the reading. Wet-bulb also accounts for the rate of evaporation in the air; it accounts for the body's ability to cool itself through evaporated sweat. When the wet-bulb and dry-bulb temperatures are nearly identical, that means that the RH is high.

We have psychrometrics charts, and we can plot points based on wet-bulb and dry-bulb temperatures. These charts also have a "dew point" on them, which is the point where the air can no longer hold more grains of moisture. That moisture then condenses into dew or fog; this point is saturation or 100% RH. Dry-bulb and wet-bulb temperatures will be the same at the dew point.

Bryan and Jamie also discuss:

Absolute moisture content (moisture grains)
What Willis Carrier understood
Evaporative or adiabatic cooling
TXVs vs. fixed-orifice metering devices and temperature
Sensible vs. latent cooling
Commissioning equipment for comfort

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Measuring Voltage Drop w/ Jim Bergmann May 01, 2017

In this episode, Bryan and Jim discuss measuring voltage drop and what it means. They also cover some other pointers to keep from using parts to bandage a deeper issue.

A common mistake that technicians make is not understanding what an ideal measurement is before making a measurement. For example, they may not know what the refrigerant pressures should be before they attach the gauges. Electrical measurements are the same, and voltage drop falls under that umbrella.

Voltage refers to electrical pressure, and current refers to electrical flow; they are two different values. The voltage will typically be at its full value (e.g., 240v) until you test the system under load. The voltage will drop when the motor begins turning. A motor will generate either motion or heat. When a motor doesn't have enough electrical pressure (voltage) to start, it will generate heat until it trips an internal overload. Upon startup, a standard voltage drop will be around 20% on a properly sized circuit. When the unit drops voltage in excess, the compressor turns more slowly and reduces its output.

Many technicians measure voltage to see if it merely exists. They do not attempt to see if the voltage is at an appropriate level, and that's a major pitfall in our industry. Technicians ought to know the appropriate voltage values so that they can assess if the voltage drops are normal or excessive upon startup and while a compressor is running.

Common issues that cause excessive voltage drop include:

Excessive heat loads in the building (from other electrical appliances)
Undersized feed wires from the transformer to the pole
Loose lugs
Corroded connections
Conductors that are too small or too long

Before bringing out the hard start kit, make sure you do all of the preliminary checks to make sure you REALLY need it. Make sure the feed wire is the correct size and that your connections are solid. A hard start kit will mask the issues of voltage drop for a short time, but they don't address the core issue.

So, just check voltage drop under load. Voltage drop should not exceed 20% on startup and 3% while running.

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Starting Up a New Chiller w/ Jeff Neiman Apr 28, 2017

In this podcast, Jeff Neiman shares an overview of his chiller startup procedure and some things he looks out for when starting a chiller after the initial chiller installation.

The actual chiller startup is typically the factory's responsibility (per the manufacturer); however, the "startup" that we're talking about refers to the installation and early maintenance.

The first step is preparation. Neiman recommends having a copy of the installation manual and reading it beforehand. You should also have a "request for startup" or pre-commission checklist. You also want to make sure there is water in the system before starting up a chiller. Technical datasheets are also useful to have on hand.

Once you get to the job site, inspection will be your main job. You can look for dents in the coils and other signs of damage from shipping or mishandling. Review the installation location. Make sure there is proper clearance around the chiller. As with other HVAC units, liquid in the compressor is catastrophic. So, make sure that the screw compressor is warm and liquid-free. Although centrifugal chillers have separate oil systems, heat is also important in those chillers because it warms the bearings.

Next, you can open up the panel and check the power. Perform a voltage imbalance calculation to make sure your voltage is satisfactory. Check for proper wire sizing and the number of conductors. Check that the piping has been done properly for the flow direction. The condenser fan has set screws, and it would be wise to verify their tightness.

Then, you check your water flow to make sure it fits all the correct parameters on your technical datasheets. Check the valves, flow, and pressures as specified.

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Hard Start Kits, Types, and Applications w/ James Bowman Apr 25, 2017

In this episode, Bryan speaks with James Bowman from Rectorseal about hard start kits, PTCR devices, run capacitors, compressor overheating, and the Kick Start product. We also go pretty in-depth on potential relays and how they operate.

Hard start kits are mechanical potential relays connected to a capacitor, and they aid in starting the compressor. They come in two-wire and three-wire types. However, they have some pitfalls. For example, they are easy to abuse. You may also come across a "hard start kit" that does not have a mechanical potential relay (such as a PTCR), which is not a true hard start. Many of those false kits are low-quality and borderline dangerous.

The start cycle starts in approximately 0.4 seconds. A proper hard start kit will help the compressor start in less than 0.4 seconds. Two-wire electronic start kits don't react quickly enough and cannot remove themselves from the circuit in time. Two-wire mechanical potential relay kits, on the other hand, measure voltage between run and start, unlike a three-wire device that measures the voltage between common and start. Three-wire devices are typically okay, but they are not a universal component that can fit every unit.

Rectorseal's Kick Start kit is an aftermarket kit designed to work on most units as a replacement for the OEM kit. When dealing with aftermarket hard start kits, the best practice is to know your equipment and the hard start kit's compatibility with the unit. Hard start kits work especially well with reciprocating compressors with long line sets and HVAC systems with hard shutoff TXVs.

Bryan and James also discuss:

Potential relays
Back EMF
Start capacitors
Testing run capacitors under load and with meters
Looking at systems holistically
Copper plating inside compressors

For more information, go to rectorseal.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Completing the Service Call Process (Part 2) w/ Les Fork Apr 21, 2017

In part 2 of this conversation, we go through the condensing unit and wrap up the call with our no-fluff customer service best practices.

The service call

A thorough inspection is critical on any residential service call. A service call is an opportunity to check the integrity of the unit and the cleanliness of the blower wheel, drain, and other components. Check the charge, safeties, and five pillars. List the problems and present the solutions as suggestions. Provide appropriate timetables and provide all necessary information. If possible, you can let the customer watch you work on their system to build that trust and teach them about the unit.

If the customer gets worked up over the pricing or frustrated over something with their unit, own the frustrating circumstance. Make sure you stay calm and rational with them. Remember, you are a consultant that they should trust, and it is best to be empathetic and professional at all times.

When exiting the call, try to move on without spending too much time chit-chatting with the customer. Offer to answer questions by giving your contact information or the office's contact information.

The Residential Service Tech Process w/ Les Fork Apr 20, 2017

This is part 1 of 2 on the soft skills practices of approaching and completing a residential service call in the best manner possible.

Before the service call and good housekeeping

Before a technician even leaves to go to work, they need to get their head in the game. Be ready to face the day by showering, shaving, and brushing your teeth. Having self-respect is also a sign of respect for the customer. The drive to work is a good place to clear your mind; you can listen to podcasts or do other things to get yourself in a good place to work effectively. Getting to work early is also a good practice.

At the beginning of the workday, you can get a coffee, restock your truck, and fuel your truck to start your day with everything you need. When going to a customer's home, make sure you have reviewed the history of the unit and get there on time. Exit your truck as soon as possible; customers expect prompt service. Introduce yourself politely and listen to what the customer says. Respect their home; don't leave your trash on their property, don't smoke, and be careful not to let the smell of cigarettes bother the customer.

Electrical Myths P2 - Grounding & Bonding Apr 18, 2017

In this podcast episode, Bryan talks about grounding and some common misunderstandings related to ground, neutral, ground rods, and lightning.

The common phrase that "current goes to ground" is a myth. The transformer (or the power source) that feeds a building creates a potential difference in charges (voltage); current is the motion of electrons between a difference in charges.

A transformer has three terminals: two legs and the XO terminal (neutral). You have 240 volts between legs and 120 between each leg and the XO terminal. The leg of power going into the transformer is split into two in a single-phase application, so the sine waves are completely out of phase with each other. When you connect to a transformer, all of the power is either a balance between the two legs or is between the legs and the XO terminal (neutral); it NEVER goes to ground. If any power is traveling to "ground," it is traveling to the ground and going back to the source because there is no other path. Power travels to the ground and then to the source when neutral isn't properly bonded to ground.

Another common myth is that the current always takes the path of least resistance. The current does not always take the path of least resistance; it may take all appropriate paths.

All equipment is grounded to create a ground fault (this is called "grounding"). Then, it should be connected to a ground rod. Grounded assemblies attempt to dissipate high-voltage occurrences, such as lightning strikes and massive surges from distribution lines. Lightning is a very high-voltage DC phenomenon that can be fatal to people or equipment. So, dissipating electromagnetic pulses to ground is much safer.

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Ice Machines and Tech Support w/ Nick Messick Apr 14, 2017

Bryan talks with Nick Messick about some ice machine basics. They also discuss how to determine when to pick up the phone and call tech support.

Ice machines have the same basic refrigeration circuit as HVAC systems. However, ice machines require a much different cleaning regimen. Many maintenance people neglect ice machines by using incorrect cleaners. You need more of a sanitizer than a cleaner; sanitizers kill germs and fungi, but cleaners work better on corrosion. When cleaning an ice machine, watch out for mold and scale buildup. Scale buildup is especially problematic because it hardens the water. You can use ice thickness probes or listening devices to determine the condition of the water (and ice). Also, use a nickel-safe cleaner, like Refrigeration Technologies' Viper Nickel Safe.

Ice machines have "harvest cycles" where ice collects. Ice falls off the evaporator when warmth hits the evaporator. An ice machine may use hot gas or "Kool gas" defrost. Hot gas defrost reverses refrigerant through the cycle and sends discharge gas to the evaporator. Manitowoc systems use Kool gas, which uses saturated vapor at the top of the receiver and results in a quieter harvest.

Tech support can really help you if you can't understand the manual or get stuck. However, some techs let their pride prevent them from calling tech support. Ultimately, calling tech support to help you understand an ice machine will save you time and save the customer money. You can also walk away from a situation having learned something new for next time if you call tech support and let them help you. However, calling tech support should NOT be a crutch that techs depend on all the time; basically, don't let them be your autopilot.

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Sometimes a #12 Wire can go on a 40A Breaker Apr 10, 2017

In this episode of the podcast, we talk about condenser wire sizing considerations, ampacity, temperature, conductor sizing, voltage drop, and why a #10 wire doesn't always require a 30-amp breaker.

There's usually nothing wrong with OVERSIZING a wire or conductor. However, you still need to know which wires are safe for operation and comply with the National Electrical Code (NEC) protocols.

Relatively small conductors can carry relatively high voltages. Instead, amperage dictates the size of the wire. Therefore, we use ampacity (amp capacity) to determine the size of a wire. Transformers are a perfect example; wires going into the transformer are small, and wires leading out of the transformer are larger. You also size circuit breakers, fuses, or overcurrent protectors to protect the conductor.

The wire type that goes into a breaker depends on several variables. Some of these variables that affect ampacity include wire material, insulation rating, ambient temperature, and how many other conductors are in the same metal area. Thus, rules of thumb for wire sizing are not reliable. If the ambient temperature exceeds a wire's rating, you can derate a wire by using a multiplier; use the values in Table 310.15(B)2(a).

A major concern for wire sizing is the probability of a short circuit. The term "short circuit" is often misused to describe ANY sort of electrical failure, but that is not the case at all. "Overcurrent" or "ground fault" is a more precise term for excessive amperage. Overload conditions indicate that the load is too large, so high amperage is drawn. Compressors draw the highest amperage out of all HVAC system components.

Overall, size your conductor by minimum circuit ampacity and your breaker based on maximum overcurrent protector

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Techs vs. Engineers w/ Bill Spohn from TruTech Apr 04, 2017

In this episode of the podcast, we talk to Bill Spohn from TruTech Tools about how TruTech Tools got its start and some of the ways that techs and engineers approach problems differently.

Bill Spohn is a majority owner of TruTech Tools who became invested in the HVAC field in the 1990s. The beginning of TruTech Tools was a milestone in Bill's professional journey. After working at Superior Valve for a few years, Bill moved to Testo. While Americanizing many of Testo's products, Bill Spohn met Jim Bergmann. A German Testo employee advised Jim Bergmann's father to set up an online store for the Testo products and other HVAC tools. That website later became known as TruTech Tools. Jim, his father, and Bill were at the forefront of the new company. Bill contributed to the development of TruTech Tools through his product and marketing knowledge. Since then, TruTech Tools has grown a lot more. Jim Bergmann has since moved on, but he is still friends with Bill and remains a major figure in the instrument development and testing part of the HVAC industry.

Bill considers himself to be an engineer. Unlike technicians, engineers have a deeper level of expertise in the development of tools and products. However, technicians have greater field knowledge and provide valuable feedback for engineers like Bill. Engineers know the math behind their products and how to use those products. However, technicians provide the practical element to tool development. Both technicians and engineers must be humble to work well together, exchange ideas, and technologically progress.

You can always get a great discount from Trutechtools.com by using the offer code getschooled at checkout.

Check out our handy calculators HERE.

Emergency Boiler Repair - Tech Ride along Apr 04, 2017

In This episode Justin talks about the trials and benefits of working out of town, long drives and this weeks boiler service calls in detail.

Ductless Installation P2 - Flaring, Charging and More Mar 31, 2017

Jesse and I talk about MORE best practices for installing ductless systems.

Both lines should be insulated on a ductless system because they have electric expansion valves in the outdoor unit. Insulating flares is also a critical task. When it comes to flare fittings, overconfidence is a tech's biggest enemy. Techs often undervalue the process of reaming copper or overdo it. Bubble-testing the flare joints is always a best practice to evaluate the integrity of your flares and check for leaks. Do not braze copper on ductless systems!

Ductless evacuations require deep vacuums. Removing cores and valving off are best practices for evacuation; the goal is to reduce the risk of contamination, just like normal split systems.

Ductless Installation P1 - Application and Drains Mar 30, 2017

Bryan and Jesse talk in detail about ductless applications we commonly see, best system placement, drains, and much more.

Ductless systems are unique, and their compact nature makes them a good choice for several small, controlled applications. These applications are in climate-controlled garages, lanais (sunrooms), and master bedrooms. In Florida, lanais are the primary application for ductless units, especially due to codes that regulate HVAC systems in lanais.

When installing a ductless unit, Jesse looks for aesthetics and reliability. Since ductless units are visible, making them look good inside the home is a concern that you don't typically worry about on split systems. When it comes to the drain line, Jesse likes using gravity drains on exterior walls. Many callbacks deal with drainage issues, so drains can reduce ductless units' reliability. Condensate pumps also occasionally have issues, so Jesse puts the pump in a way where all connection points are below the ceiling to avoid ceiling damage. However, float switches and overflow devices may also be required by code and may help.

Combustion Basics w/ Benoit Mar 22, 2017

In this episode with BENOÎT MONGEAU, we talk about the components of combustion and what to consider when testing it on a fuel-burning appliance.

Combustion requires fuel, oxygen, and a heat source in a correct balance. We call that series of requirements the "combustion triangle." Once combustion occurs, it is self-sustaining. However, removing one element of the triangle will end combustion. (For example, you could suffocate a flame by removing the oxygen content.) Undesirable consequences of incomplete combustion include the production of carbon monoxide, a potentially fatal gas. Flash point is the temperature at which vapors can ignite.

Excess air is the air that you're inputting into flue gas that doesn't get used for burning. It contains nitrogen and oxygen and doesn't contribute to the burning. However, it does expand the volume of the flue gas and absorbs heat. Excess air indicates a loss of efficiency and colder gas. (Note: Perfect efficiency is theoretically possible but impractical.) High-efficiency furnaces have longer run times, which may confuse customers; customers may think that the longer run times mean that there is something wrong with their heating system.

Natural gas is mostly methane, so it is easy to burn with the right amount of oxygen. Propane (liquid petroleum) is a larger molecule with three carbons. Propane requires more time and more mixing for proper burning. The larger the molecule, the more time you have to spend waiting for combustion, and it's harder to burn the molecule completely and properly.

Benoit uses Testo combustion analyzers and TPI digital manometers when working with furnaces. He uses heat-rise calculations whenever he wants to calculate CFM on a furnace. CFM tables are in the manufacturer's manual.

As always, if you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

HVAC Ridealong - Leak Detection, Repair & New Smart Probes Mar 22, 2017

In this episode Justin talks about his first A/C repair of the season, his old combustion analyser and why he is enjoying the Testo Smart Probes his just got

What Circuit to Break, Makeup Air, Chiller & Boiler Startups and More - HVAC Tech RideAlong Mar 17, 2017

Pumping Away and More w/ Dan Holohan Mar 13, 2017

Dan Holohan speaks to Bryan about his background and journey as a writer. He also dives into his book, Pumping Away, and describes classic hydronics as he does in his book. Bryan and Dan also briefly discuss the difference between search and research.

Dan is a prolific writer, and one of his most famous works is The Lost Art of Steam Heating. However, this episode primarily focuses on Pumping Away: And Other Really Cool Piping Options for Hydronic Systems. Although Dan has retired, his daughter has ensured that his books will continue to remain in publishing for years to come.

Pumping Away is about the piping genius of Gil Carlson. Carson was one of the founding fathers of hydronics. Carson's main contribution to hydronics is the idea that circulators need to pump away from compression tanks. Hydronics systems use steam, hot water, and gravity furnaces for heating. Boilers and radiators were not common in the public sphere at that time. As Dan describes in his book, hydronics is a relatively old technology. Many American buildings used hydronics to control the temperature in buildings before the days of World War II. Dan's conversational prose and easy-to-understand drawings bring hydronics to life in his readers' minds.

Dan's advice for the new generation's technicians is to recognize their value. When young people recognize their value, they can take ownership of their knowledge. However, empowering the next generation also requires new technicians to share their knowledge readily. The trade thrives when technicians share their knowledge and don't see the trade as a competition where people try to get a jump on each other.

Once you are done listening, please head over to heatinghelp.com.

As always, if you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Why Maintenance Agreements Matter and How to Make Them Work w/ Ruth King Mar 08, 2017

In this episode, Ruth King shares some of her top insights on how to create a maintenance program if you don't have one. She teaches us to recognize a broken program and fix it.

The maintenance component of your company will be the part of your business that allows you to grow your business profitably. If you don't believe in maintenance agreements, your customers won't believe in those maintenance agreements either. Without maintenance agreements, your company will have sharply different slower times and busier times. You'll likely have to pay employees to stay in slow times, and it is not very profitable.

Getting a maintenance agreement plan in motion is as easy as getting a maintenance agreement form. Inform your customers of the benefits of maintenance (saving money on utility bills, extending equipment life, etc.). Then, offer it to your customers; you don't even have to make it sound like a sales pitch. Some of your existing customers will almost surely agree to the maintenance agreement.

When you enroll someone in a maintenance agreement, it is a good idea to put that money in a separate savings account. The cost of performing the maintenance can be taken out of that savings account, but you would have ideally already set some money aside solely for operation costs. To make sure you're at least breaking even on your maintenance agreements, you must make sure you factor in hourly pay, cost of goods sold, and overhead costs. You can calculate overhead costs by checking the previous year's operating expenses and dividing that by your billable hours.

If you are interested in Ruth's maintenance program course, you can find out more HERE. Be sure to use the offer code HVACRS (with all caps) to get a 10% discount on all her products.

Profitability and Money Leaks in HVAC w/ Ruth King Mar 07, 2017

In this episode, Ruth breaks down some of the main things an A/C contractor needs to consider when looking at their numbers and some of the major leaks that can lead to unprofitability.

Profit and loss (P&L) statements are critical for determining the profitability of your business. You can use it to find money "leaks" in your business model. When making P&L statements, ensure that the revenue AND costs for a given product are in the same month for best accuracy.

Most small businesses don't look at their profit and loss statements at least monthly, which is the best practice for keeping track of money via a P&L statement. Most businesses also don't separate overhead from cost of goods sold. Overhead costs don't DIRECTLY contribute to the business's revenue. Examples of overhead include rent, electricity bills, and office staff paychecks. Some other common profit drains include marketing and insurance expenses. However, perhaps the largest potential money drain is a lack of employee productivity. A vast majority of small business employees "steal" from their employers by using work time for personal activities.

You also want to run your business on an accrual basis than a cash basis. You can keep better track of your expenses and income automatically, not ONLY when you pay your expenses or when money comes in through the door. QuickBooks makes this an easy process.

You know that your business is profitable if your P&L statements end up with a positive number. On top of that, you can determine your net profit per hour. Take your net profit and divide it by billable hours (no vacation time, office staff wages, etc.).

You can see all of Ruth's content and courses HERE. Make sure to use the offer code HVACRS with all caps for a great discount.

Should I Start My Own Business? w/ Tersh Blissette Mar 06, 2017

Tersh and Bryan were both techs working for other companies when they started their own businesses. This episode is a look back at what they got right, what they got wrong, and the top things that have worked over the years.

In general, there are two types of HVAC business owners: the sales/business type and the technical type. Bryan and Tersh are both of the technical variety. These types of owners may be less familiar with the ownership and business organization side. Many current technicians will find themselves in a similar position if they decide to go into business.

The HVAC industry is NOT as profitable as many people imagine it to be, especially in the early years. Tersh recommends that technicians really research the expenses of HVAC business ownership, namely worker's compensation, general liability, licensing, fuel expenses, and advertising. He also recommends that business owners use digital media to assist their business operations.

Bryan encourages prospective business owners focus on their financial literacy. You can be excellent with customer service and can draw many customers to your business, but those qualities don't matter if you can't manage your money effectively. Business owners need to understand what profit REALLY is, how margins work, and how to evaluate and nurture a successful business model. Also, business owners should track labor rates and know who to compete with; don't compete with businesses that do bad work or are going out of business.

You must also have good people skills if you want to start an HVAC business. If you cannot be empathetic and build relationships, running an HVAC business isn't for you. Bryan and Tersh both agree that the best overall mindset for an HVAC company's business model is "People over profit." That includes service technicians, customers, and all staff.

Test Instruments Past, Present & Future w/ Jim Bergmann Feb 28, 2017

In this episode, Bryan speaks with Jim Bergmann of Redfish Instruments about his path to being a test instruments business owner. He has also worked with Testo and has teaching experience under his belt.

In the past, test instruments were low-resolution and often inaccurate. Many HVAC techs of the past based all of their knowledge on inaccurate measurements. We also didn't use many of the best practices we use today. For example, technicians used tap water for sling psychrometers, not distilled water. As such, technicians of the past had serious issues with wet-bulb enthalpy calculations. Some of these challenges stemmed from issues with the educational system. There was a lack of emphasis on the fundamentals and measurement and an overemphasis on installation, and the poor curriculum still persists in some institutions.

Today, Jim sees a large understanding gap between the engineers that develop test instruments and technicians in the field. As a business owner who developed some of those testing technologies, Jim's goal is to close the gap.

In the future, Jim believes that the HVAC labor shortage will be a challenge for test instrument developers as the industry moves forward. Due to issues that remain in the HVAC education system, Jim also worries that the people who enter the field will be "parts-changers;" they won't check the system thoroughly for a proper diagnosis. So, Jim has been working on a diagnostic tool called MeasureQuick to help new technicians by educating them on what their readings mean. These technologies are meant to help entry-level techs and aid intermediate and senior techs.

Here's a bonus note about measuring with pitot tubes: use longer hoses and an instrument with a very high resolution.

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Condensing Temperature, Condenser Split and Subcool Feb 22, 2017

In this podcast, Bryan talks about condensing temperature, condenser split, and subcooling. All three of the values are proportional. If one changes, all three of them will change. Saturation is also a critical concept that relates to all three of those, so we also cover those relationships.

As you remember, a condenser rejects heat and turns vapor refrigerant back into a liquid.

Condensing temperature is the saturation temperature at which the refrigerant changes from vapor to liquid; it can change depending on ambient temperature. While in the condenser, the refrigerant will be at saturation and be a liquid-vapor mix throughout most of the coil.

Subcooling indicates how low a liquid is below liquid-vapor saturation. For example, if you had a condensing temperature of 110°F and took a liquid line measurement of 98°F, you would have 12°F of subcooling (110 - 98 = 12). Although some high-SEER HVAC systems may get their liquid line temperatures pretty close to the ambient temperature, you cannot have a liquid line temperature below the ambient temperature. Otherwise, you probably have a restriction in the line. Many technicians set a charge based on subcooling.

Condenser split is a bit trickier to define. You DON'T compare the temperatures of air going into the condenser and air going out. Instead, it is the difference between the condensing temperature and the outdoor temperature. The outdoor temperature MUST be lower than the condensing temperature. Otherwise, heat rejection cannot take place. In general, most manufacturers tend to engineer their HVAC systems to maintain a 15-30°F condensing split.

Heat mode has its own set of challenges. For example, subcooling can be difficult to predict in heat mode. However, between 20-30°F of subcooling in heat mode is normal.

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Air Flow - Latent, Sensible, WB, DB, RH and Static Feb 16, 2017

In this episode, Bryan talks a bit about the air side of the system. Understanding airflow is all about seeing the relationship between readings. We cover latent and sensible heat, relative humidity, wet and dry-bulb temperatures, and static pressure.

Latent and sensible heat refer to heat that we can feel (sensible) or heat that contributes to a phase change and cannot be felt (latent). Both latent and sensible heat have a major impact on equipment sizing, especially in coastal regions and other areas where humidity is naturally high. When we attempt to control sensible and especially latent heat, we have to look at the airflow over the evaporator coil. When you run the blower more slowly, you pull more moisture (latent heat) at the expense of efficiency and capacity. Therefore, for peak capacity, efficiency, and sensible heat removal, you will want to max out the blower speed.

Delta T (or air temperature split) is another important reading. Delta T is the temperature differential from the return to the supply. When you measure delta T with a dry-bulb thermometer, you will only get a sensible heat measurement. You need a wet-bulb temperature reading to account for humidity and latent heat changes. Relative humidity (RH) is the ratio of moisture in the air compared to the maximum at that temperature. Therefore, wet and dry-bulb temperatures are the same at 100% relative humidity.

Static pressure is an indicator of airflow, but it isn't airflow. Static pressure is essentially resistance pressure that exerts itself on all surfaces. It is not the force of air flowing through the duct (that's velocity pressure).

Also, consider adding a differential manometer to your toolbox. They make measuring TESP a breeze.

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New Series Pilot - HVAC Tech Ride Along W/ Justin Skinner Feb 11, 2017

In this first episode of a new series Justin talks about the calls he is doing before and after he does them, giving us a look inside the van of a senior HVAC tech.

Hard Start Kits, Staybrite #8, Motor Ratings, AHR and Much More Feb 08, 2017

In this episode of the HVAC School Podcast, we talk about some cool technologies and controversial tools.

Joe Shearer joins us to talk about hard start kits. Some people believe that hard start kits are only suitable for one-time use, but Joe and Bryan believe that there's a lot more to it than that. If hard start kits are high-quality, then you could leave it on. However, if a unit has a hard-shutoff TXV, then it absolutely needs a hard start kit. Many techs are still hesitant about using hard start kits because they can damage the compressor if the relay doesn't take them out.

Some techs feel similarly towards Stay Brite #8. You don't have to flow nitrogen with Stay Brite #8 solder, and some technicians (Bryan included) are suspicious about the quality of the work when you cut out those critical steps. So, many technicians prefer brazing, but Stay Brite #8 and brazing each have their benefits and drawbacks.

At AHR, Bryan got a chance to speak with FasTest representatives about CoreMax valve cores. These large cores are great for commercial HVAC applications and help you achieve high flow during evacuation. Your typical core removal tools won't work, but CoreMax core removal tools exist, and the core assembly is also easy to replace. He also got to speak to a Packard representative about motor temperature ratings, especially on OEM vs. aftermarket motors and motor performance in various ambient conditions. Browning shared some information about their notch belts and the temperature ratings of those belts.

Also, remember to check that the discharge temperature stays below 220°F. The discharge temperature can tell you a lot about your compressor and your chances of experiencing oil breakdown.

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Low Ambient, Condenser Flooding, and Headmaster Valves Feb 03, 2017

In this podcast episode, Jeremy Smith comes on the podcast to talk about low-ambient controls, headmaster valves, charging, and condenser flooding.

If our head pressure drops too much, we won't get enough of a pressure drop across the TXV. Pressures dictate the TXV function, so we need to make sure our systems give that valve what it needs to operate correctly. Three pressures operate a TXV: bulb pressure, spring pressure, and evaporator pressure. However, pressures throughout the system can also affect the pressures that act on a TXV.

Condensers are sized for maximum heat rejection at the highest ambient temperatures a unit will experience. Low-ambient controls help get your liquid pressure up by effectively reducing the condenser's capacity. One common thing we can do is use a fan cycle; a pressure control can turn the fan on and off, but you can see large pressure swings.

We can also use headmasters, which maintain head pressure by backing up liquid in the condenser; it fills the condenser with liquid and shifts some discharge gas to the receiver to maintain the receiver pressure. Headmasters are NOT adjustable in the field. When diagnosing headmasters, try to look for leaks first; Jeremy thinks many headmaster failures could have been misdiagnosed.

Split condensers can shut off parts of themselves to reduce capacity, which can serve as another low-ambient control without bypassing discharge gas or wasting energy.

You may also come across some adjustable controls that allow you to adjust your head pressure by setting receiver pressure and other similar values.

Jeremy and Bryan also discuss:

Balanced-port TXVs
Fan cycling in air conditioning
Using a clear sight glass to charge refrigeration units
Headmaster part numbers
Carrier Motormasters
Parallel rack systems and remote condensers
Inefficiency and bypassing discharge gas

Read the companion tech tip HERE.

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Bonus - How Sibling Rivalry Built an Empire Feb 01, 2017

Bryan takes a break from the technical talk and tells a quick story about how two brothers fueled an industry and created an empire with raw sibling rivalry. Bryan co-owns a family business, and we understand that many people in this trade work with family, so we hope you'll enjoy this story.

Many of us are competitive, and nobody enjoys failing. We especially try to avoid failing in front of our family members. However, the drive to succeed and avoid failure can sometimes get a bit out of hand.

In the early twentieth century, two brothers named Adi and Rudy Dassler worked in their father's shoe business. Rudi was the more outgoing older brother; Adi was younger, quieter, and focused on making shoes. Business practices had changed as industrialization occurred across Europe, and many shoes were made in a factory instead of by hand. With all of the innovation going on at the turn of the century, both brothers realized that they, too, could own a factory.

After serving in World War I, Adi began making shoes in his mother's laundry room. Rudi talked their parents into helping start up a shoe business. The brothers established their own athletic shoewear company, which became popular with help from the Modern Olympic Games. Adi approached Jesse Owens, a famous African-American track athlete from the United States, to wear his shoes in the Olympics. Jesse wore the shoes to victory, angering many Nazis. Rudi was the more ardent Nazi, and a rift started between the brothers.

Rudi was arrested for war crimes during World War II, though historians suspect that Adi may have snitched on him. The sibling rivalry came to a head in 1948 when Rudi officially split from the company and formed Ruda. Adi formed Adidas, which was more successful than Ruda (now Puma).

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Chiller Talk for the Chillerphobic Jan 27, 2017

In this episode, we talk with Jeff Nieman about chillers and how they work.

For those of you who primarily work in residential or light commercial HVAC, chillers may be unfamiliar at best and terrifying at worst. However, centrifugal chillers' parts are actually quite similar to those of HVAC units. They have an evaporator, compressor, condenser, metering device, and control system, just like the HVAC units we see every day. Jeff believes that breaking a chiller down into its parts is the easiest way to become comfortable with it.

Chillers are used for comfort cooling and process cooling. In comfort cooling, chillers discharge cool water (44°F) to the building. From there, air blows over the water to cool the space. For process cooling, chilled water flows through machines that require constant cooling to operate correctly, such as laser-cutting machines and MRIs. As you can see, chillers simply absorb and reject heat, just like standard compression-refrigeration HVAC systems. However, unlike traditional compression-refrigeration units, chillers have an independent oil circuit.

Preventive maintenance is a major part of chiller work. You can tell a lot by listening to a chiller and looking for oil or water on it. You also check superheat, subcooling, and water temperatures. Service calls also require technicians to engage their senses. Most issues deal with low water flow, building issues, and dirty strainers in the condenser water piping.

Bryan and Jeff also discuss:

Two-way and three-way valves
Glycol and freeze protection
Alarms (float switch, low evaporator pressure, high condenser pressure)
Chiller troubleshooting
Impellers and inlet guide vanes
Suction in negative pressure
Fan coils
Chiller water
Screw chillers

Also, Bert and the Testo 770-3 make an appearance.

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Check out our handy calculators HERE.

Leak Detection Mindset Jan 23, 2017

In this episode, Bryan and Bert talk about properly stripping cables and leak detection best practices. Bert is a senior technician and self-proclaimed leak detection expert.

As a slight aside, Bert CAN'T STAND when technicians strip wires. Basically, his advice is NOT to cut around the wires or use a razor knife.

Leak detection starts when you walk up to a unit and confirm that the unit is low on refrigerant. Typically, you hook up gauges and check the five pillars. You will particularly check for low superheat and high subcool. However, your senses are also important during the confirmation process. Use your eyes before even grabbing a leak detector. You can typically spot corrosion on the line set, coil, or pipe fittings. Then, you can perform a bubble test to confirm the leak without a tool.

Bert starts with coil and checks for oil spots. He then feels brazing joints for oil (even though that sounds a little suspicious). Most importantly, if Bert suspects a leak, he does his bubble test BEFORE pulling out the electronic leak detector.

When Bert uses the leak detector, he turns it on and lets it stabilize for a little bit. He starts LOWER on the coil to get a hit and starts HIGHER to pinpoint the leak. And NEVER put your probe in water!

New coils can be tricky. Although they CAN leak, it's improbable. If your leak detector gets a hit on a brand new evaporator coil, it could be caused by the chase. You MUST confirm that the leak is on the coil; it's not good enough to say that there is a leak without knowing exactly where the leak is coming from.

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Recovery, Evacuation, and Dehydration Facts Jan 12, 2017

n this episode, Bryan covers evacuation, recovery, and dehydration.

Evacuation refers to putting a vacuum pump on the system and pulling it down. We use a few different measures of vacuum, including inches of mercury ("Hg) or microns (millionths of a meter of mercury). We use such small units to measure a vacuum that effectively boils off moisture in the system. You must pull the vacuum very close to a perfect vacuum. So, a measurement of 500 microns indicates that the vacuum is 500 microns of mercury above a perfect vacuum.

Dehydration is a mere component (or result) of evacuation. If there is excess moisture in the system, it can freeze inside the system and cause blockages. It can also interact with oil and refrigerant inside the system to create an acid that ruins your unit.

To get a proper vacuum, you have to pull down to 500 microns. You can go lower than that, if possible, but 500 microns is the industry standard. Remember that Schrader cores restrict your vacuum. Remove them with a proper core remover tool for a more effective evacuation. Larger hoses and better equipment won't make a difference if you leave those Schrader cores in. If you don't have Schraders, you probably have a service valve.

Recovery removes refrigerant from a system under vacuum and puts it in a tank. We do recovery because we CANNOT vent refrigerant.

As a best practice, when you connect your vacuum rig to the port, you can use a little bit of Nylog thread sealant to keep moisture and other contaminants out.

Bryan also covers:

Push/pull method
Microns
Vacuum pump oil
Moisture contamination
Vacuum restrictions
Triple evacuation and sweeping nitrogen
King valves/service valves
De minimis

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Building a Great HVAC Business w/ Bob Gee Jan 09, 2017

In this episode, Bryan talks to Business and Sales Trainer Bob Gee about HVAC business practices.

Bob has watched sales and leadership evolve a lot over the years. Today, success in sales depends on your abilities to build relationships with the customers. You're no longer "selling" things; you are "helping people buy" things. Instead of pushing products to people, it's best to "ask your way into a sale" and prioritize a customer's wants and needs. There is also a stark difference between management and leadership. A leader is people-oriented and customer-oriented; they care about the human element of business, not just crunching numbers.

When it comes to building a company culture, the company leaders have to be the ones to create the team. You have to get the right people on board and delegate them in a way that maximizes those people's potential. Business leaders also need to examine their own purpose. Why are they running the business? Do they want to commit to the business, or did they just decide to work independently to have more control over their own schedule? Motives mean a lot, and the managers' attitudes trickle down.

Firing people and having people leave are unfortunate but inevitable parts of running your own business. People tend to leave people; they don't necessarily leave the business because of the money or the type of work. Employees have to be on board with the managers' ideas of what the company is doing and where it should go. If they are not on board, they will quit or may have to be let go after their work quality slips over time.

Follow Bob Gee HERE.

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Check out our handy calculators HERE.

Combustion Analysis w/ Stephen Rardon Jan 03, 2017

In this episode, Bryan talks to YouTube star Stephen Rardon about combustion analysis.

In Florida, we mostly have A/C units and heat pumps. High-efficiency furnaces are not in our wheelhouse, but furnaces are more like A/C units than you would imagine. Stephen Rardon makes some excellent comparisons between the two.

For example, you can get an idea of how an A/C system is running without checking superheat and subcooling. With a gas furnace, you can get an idea of how it's running without checking combustion. Of course, these are both general, and you lose out on knowing the specific parameters. In a sense, oxygen (O2) and carbon dioxide (CO2) in a high-efficiency furnace can be compared to superheat and subcool on an A/C system.

Going even further, we could say that a furnace's stack temperature is equivalent to airflow. Stack temperature indicates if the system is moving enough air to pull the heat off the heat exchanger. If the furnace can't adequately heat the air, then we have to look at how it's moving air in the first place.

Meter clocking is a bit controversial. There is an attitude that clocking meters doesn't matter, especially among old-school techs and ones who don't have a lot of experience clocking meters. However, it is a vital step for accurate combustion analysis. Knowing how many BTUs the system is dumping is a useful measurement, especially for diagnosis. You could compare it to a delta H reading on an A/C system; the number likely won't affect the outcome, but it helps you learn more about the system.

Bryan and Stephen also discuss:

Stephen's HVAC YouTube journey
Gas furnaces
Underrated readings
Fancy diagnostic tools

Follow Stephen HERE.

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For 6% off of tools go to HVACRschool.com/trutech offer code = getschooled

Big thanks to Carrier & Carrier Enterprise for their generous support of HVAC School.

Circuit Board Diagnosis Basics Dec 28, 2016

In this unedited episode of HVAC School, Bryan and Nathan talk about some basic rules for circuit board diagnosis.

So, circuit boards are boards with circuits in them. They come in two types. The traditional printed variety contains switches, relays, and resistors. The other type contains silicon chips and uses logic and processing inside the boards. You may notice these in some high-end commercial systems (EMS), but we rarely see them in residential HVAC.

The diagnostic challenges come in when technicians are unfamiliar with what's on the circuit board. It helps to break it down and look at one thing at a time. Yes, there are lots of wires and relays. You may not know what it does. Take your time and get to know where everything goes and what the components are doing. Techs often misdiagnose boards because they simply don't understand how it works, and many of them don't make the effort to understand it.

It may help to look at the overall purpose of the board. For example, a defrost control simply initiates and terminates defrost. It controls the condenser fan, reversing valve, and heat strips, all of which have a function in the defrost process.

If you have a short on the board (no-load path), you will see arcing somewhere. You would most likely see melting on the board if that were the case.

If you have a board that has failed open, the switches are closed, and there is an input. However, the board doesn't travel through the time delay to bring on the contactor.

Bryan and Nathan also cover:

Isolation diagnosis
Best practices
Pulse-width modulation (PWM)
"Ghost voltages"
Jumper wires vs. meters for diagnosis
Blown fuses

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High-Efficiency Furnace Basics & Maintenance Dec 19, 2016

Benoit Mongeau comes on the podcast to talk about high-efficiency gas furnace basics and maintenance practices.

When maintaining a high-efficiency gas furnace, you typically don’t have to worry about cleanliness in the same way you’d worry about an oil furnace. However, condensate drains need regular cleaning. You’ll want to look for cracked heat exchangers and pay attention to your manifold gas pressure.

We also have to check the temperature rise, also sometimes called delta T. Bypass humidifiers will often affect your temperature split, so that's something you need to account for in cold, dry climates; hot air will go from the supply plenum to the return. (However, corrosion typically isn't a concern for bypass humidifiers.)

Water is a product of combustion, so drainage is very important to gas furnaces. Manufacturers tend to recommend that most high-efficiency furnaces be built slightly pitched to aid condensate removal. Since the combustion air contains moisture, the condensate ends up being quite acidic; that condensate is really a mix of condensed combustion products.

Combustion analysis is also an important part of maintenance. If your gas burns incompletely, the furnace will end up making deadly carbon monoxide, which is the main value we measure in combustion analysis. Typically, the carbon monoxide levels should stay below 100 PPM. You can do your combustion analysis anywhere in the flue pipe as long as you're past the inducer motor. (Note: the exhaust pipe should never be above the air intake.)

A liquid petroleum (LP or propane) furnace differs from a gas furnace because it has different pressure needs. You may also have to add a restriction to the burners.

Benoit and Bryan also discuss:

Air intake drains
“Condensing” gas furnaces
Inducer motor types
High vs mid-efficiency furnaces
Excess air
Low-fire vs. high-fire gas pressure and potential effects on combustion

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Cutting Compressors, iManifold, and Thermal Imaging w/ Ulises Palacios Dec 16, 2016

In this episode of HVAC School, Bryan talks with Ulises Palacios about some cool technology.

Ulises has become a technology expert through his many years of working with new tools. He has recently been involved in testing new technologies, and he has worked with Jim Bergmann.

Cutting open a compressor is one of the most useful diagnostic tools you can use on a failed compressor. It is also an excellent way to learn more about your equipment. They help quite often with burnouts and mechanical failures. Although winding damage is an electrical issue, other mechanical failures cause winding damage and arcs.

Copper plating is relatively common in compressors. However, it makes compressor failure even more likely, as copper can be easily corroded by acid. Copper in the bearing surfaces can corrode due to moisture, manufacturer additives, and industrial byproducts in the condensing unit. Additionally, POE oil mixes with moisture to make acid. Older mineral oil (MO) does not react with moisture to the same degree.

The iManifold is an expensive but convenient and helpful piece of technology. It takes the information required for the five pillars of HVAC diagnosis. It saves you time on the job site and gives you all of the readings you need. You input the tonnage, SEER rating, and refrigerant to help with diagnosis. The iManifold also syncs up to an app on your phone.

Thermal imaging is not just cool. Like the iManifold, thermal imaging can also be a helpful tool for diagnosis. It can be useful for duct inspections and locating restrictions. It also doesn't have the same accuracy concerns as infrared thermometers because it compares temperatures in an area.

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Check out our handy calculators HERE.

Heat Pumps, Reversing Valves and Defrost Dec 05, 2016

In this episode of HVAC School, Bryan covers the basics of heat pumps.

Heat pumps are common technologies in Florida. They reverse the sequence of the typical refrigerant circuit: the indoor coil can become the condenser, and the outdoor coil can become the evaporator. Heat pumps can achieve that transition via a reversing valve, which changes the directions of the suction and discharge lines. They also have two metering devices.

Reversing valves contain a solenoid (typically 24v) that rediverts the suction and discharge lines via shifting the slider with a pressure differential. Pilot tubes shift gas from one side of the slider to the other, which shifts it and triggers heat mode or cooling mode. Reversing valves are typically energized in cool mode (except for Ruud/Rheem reversing valves; they energize in heat mode).

Defrosting is rarely necessary for us in Florida, but it can be a scary occurrence when we do need it. The outdoor coil can freeze over entirely when it gets cold enough due to Florida's high humidity. Hot gas goes through the coils during defrosting, and it may make alarming noises. Many Floridian heat pumps also use auxiliary heat strips to provide heat while the system defrosts. Many defrosts rely on set times and sensors to determine when to initiate and terminate defrost. (That is true of heat pumps AND most refrigeration systems.) Thermistors are common sensing technologies used in defrost.

Join Bryan on this informative monologue about:

Reversing valves
Aux heat
W and W2
Heat Pumps
Defrost
Checking refrigerant charge in heat mode
Heat mode expansion valves
Common heat pump considerations

For a more detailed written explanation of heat pump reversing valves with pictures, check out this article.

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Relays, Sequencers, Transformers and Questionable Metaphors Dec 01, 2016

In this episode, Bryan and Nathan have a banter-filled conversation about electrical components that confuse techs. If you are looking for a serious educational episode, we suggest you look elsewhere.

Low-voltage circuits may confuse the new technician because the "common" terminology is far too common in the circuit. (See how confusing it sounds in everyday use? We don't have to say "common this," "common that," but we do.)

Single-phase power can also be confounding for technicians. One phase of line voltage comes in, and it gets split when it enters the circuit. That is why we also call single-phase power "split-phase" power.

Another perhaps surprising area of confusion is normally open (NO) and normally closed (NC) switches. Water metaphors could potentially contribute to the confusion, as shutting off the faucet seems analogous to "closing" a circuit, but it actually has the same effect as "opening" a switch. As instructors, we need to clarify that "open" and "closed" are different from doors, faucets, etc. "Open" means that there is no path, and "closed" means that there is a path. "Normally" merely indicates the state of the switches when nothing is happening.

Sometimes, transformers can be difficult to understand. A transformer is an inductive load that alters voltage and "steps it down" to a secondary voltage. Loads are what "do something" in a circuit, like a light bulb or motor. Inductive loads are magnetic (motors and transformers), and resistive loads create heat (light bulbs and toasters). Inductive and resistive loads are perfect subjects for PG-13+ metaphors, as Nathan demonstrates.

Join Nathan and Bryan on a vulgar learning adventure of bad metaphors as they discuss:

Relays
Sequencers
Inductive loads
Resistive loads
Blower/heat interlock
Transformers
Contactors

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Some High Voltage Electrical Basics Nov 29, 2016

This podcast is a high voltage A/C electrical class that Bryan gave to some of the Kalos apprentices.

The high voltage journey begins with basic electrical theory. Basically, a difference in charge is needed for electrons to move and generate power.

Motors, which are inductive loads, are the greatest users of power that we will encounter in the field. Inductive loads generate magnetism and utilize alternating current (AC) power. AC power is generated by a rotating magnetic field, and the direction of the current alternates. Comparatively, resistive loads generate light and heat, and direct current (DC) moves in one direction. Theoretically, we can use Ohm's law in the field to determine the voltage, amps, or resistance (ohms) without a meter, so long as we know two of the three values. However, we may not get an accurate measurement of ohms due to reactance on inductive loads.

The windings you will encounter in the field include common, start, and run. (Remember: the same side that feeds start feeds run.) In a PSC motor, the start winding stays in the circuit the entire time. When you ohm the windings, you will notice that common has the lowest resistance, run has moderate resistance, and start has high resistance. (Common to run + common to start = run to start). Universally, capacitors contain a brown, black, white, and brown-and-white wire. You can wire a capacitor in two different ways; one uses three wires, and the other uses four. The three-wire method caps off the brown-and-white wire, leaving it unused.

Join Bryan and the apprentices in their high voltage class as they cover:

Basic Electrical Theory
Potential Difference
Basic Capacitance
Motor Lead identification
Different motor type
Motor Direction
Proper Wiring
MOCP and MCA

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Gas Furnace Sequence of Operation w/ Justin Skinner Nov 22, 2016

In this episode, Bryan talks to Justin Skinner about the standard gas furnace sequence of operation.

Regardless of the furnace type, it all begins with a heat call on W...

Then, the furnace checks the safeties to make sure ignition is possible and safe. If all systems are a go, the inducer motor comes on and clears a path for the exhaust. The furnace then proves that the path for the flue is clear, and a pressure switch closes upon sensing a pressure differential. The miracle of ignition comes next. There are a few different types of ignition, including hot-surface, intermittent spark, and standing pilot. Once the furnace opens the burner, it has to prove the flame.

Proving flame is somewhat similar to proving the flue path. A flame sensing rod creates a potential, and it determines if a flame is present by picking up microamps of current to ground. We're merely scratching the surface here, but the bottom line is that the furnace does a lot of checking and proving throughout the startup procedure.

Above all else, remember to check the fault code if the sequence of operation fails to complete. The absolute WORST thing you can do is restart the furnace, take the door off, or turn the furnace off. You lose a major troubleshooting clue.

Join Bryan and Justin as they talk about these furnace sequence topics:

Low Voltage Wiring
Boilers
Forced and Natural Draft
Flame rectification
Cleaning Flame Sensors
Gas Pool Heat
Silicon Nitride and Silicon Carbide
Hot Surface and Intermittent Pilot

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Prepping Non-techs for Winter Nov 21, 2016

Central Florida techs know the Southern winter all too well. Let's face it. It doesn't get super cold here regularly, but when it does, EVERYONE FREAKS. We get an abundance of service calls for unpleasant but not truly problematic conditions when people use their heaters.

When people first turn on their heat, they can get a nasty surprise: a horrible dirty-sock smell and sometimes a shrieking smoke alarm. These are normal, albeit unpleasant, and do not require a service call. Another unpleasant or alarming occurrence is when a heat pump unit goes into defrost mode. Defrost mode shifts the unit into cooling mode, which may make some cold air come out of the vents. On top of that, customers may hear an awful noise and feel concerned when they see steam coming out of their unit!

Pool heaters are a completely different animal in a Southern Winter, and they are often made quite poorly. You may come across gas pool heaters, propane pool heaters, heat pump pool heaters, and even solar ones. Each type has its own set of maintenance needs and varying degrees of effectiveness. When working with them, the goal is to set establish realistic expectations and explain best practices to the customer to minimize those frustrating service calls.

In this episode, we talk about:

Burning off heat strips
Heat pump defrost mode
Gas pool heater
Heat pump pool heaters
The thermodynamic principles of heat pump heating
Defining BTUs
Liquid petroleum (propane) vs. natural gas

And much more...

This podcast is in an unedited "meeting format" and is not usually the type of thing you will get on HVAC school, but I still think it may benefit junior techs and office staff.

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Some Refrigeration Thoughts for A/C Techs Nov 17, 2016

In this episode of the HVAC School Podcast, Bryan talks with Jeremy Smith about refrigeration tips, terms and processes. They also cover the similarities and differences between A/C and refrigeration.

Being on-call as an A/C tech is not all that different from being on-call as a refrigeration tech. Similarly, the principles of heat transfer don't change between the A/C and refrigeration trades. Both trades follow the same basic rules, but all of those valves, adjustments, and tuning on rack refrigeration systems may make an A/C tech's head spin.

Refrigeration techs may come across glycol chillers, rack refrigerators with several refrigerant circuits on a single piece of equipment, or piping that has been warped by hot gas defrost. There is also a greater emphasis on regulating suction pressure rather than merely measuring it, and refrigeration techs use EPR valves to help control that pressure. Each refrigerated case also has its own expansion valve.

Jeremy also covers the complexity of defrost. In A/C, defrost could be as simple as shutting a unit off for a period of time. Defrost is more critical in low-temperature applications, though hot gas defrost may damage pipes and make them prone to leaks. Electric defrost typically has a lower potential to cause damage.

Also, subcooling is less of a big deal in refrigeration. Sight glasses and receivers make subcooling less vital than it is in HVAC.

Join Bryan and Jeremy as they discuss:

Reznor startup
Being on call in the refrigeration world
Differences and similarities between rack refrigeration and A/C
Hot gas and electric defrost
Glycol refrigeration systems
Subcool and superheat
Refrigeration TXV settings
EPR valves and their settings
Rack manifold pressure

And many more refrigeration tips...

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Flow Nitrogen Great Again Nov 10, 2016

In this episode of the HVAC School Podcast, Bryan talks with Tim Bagnall about flowing nitrogen.

Many techs don't flow nitrogen. Some may say that it is overkill, but it has been shown that flowing nitrogen displaces oxygen while brazing and prevents harmful scale from forming on the copper. Scale is very problematic, and it will likely ruin your copper lines if you keep those lines open to air. (The jury is still out as to whether climate/geography affect scale formation, though.)

There are many different intensities for flowing nitrogen, particularly high-pressure purging and low-pressure flowing (2-5 SCFM). You may also have heard that you should flow nitrogen at 1.5-3 PSI, though SCFM is the preferred unit. Some best practices for flowing nitrogen while brazing include using wet towels or heat-resistant putty on the service ports, removing the Schrader cores, removing the TXV sensing bulb before brazing, and watching your torch control so that you do not overheat the metal.

Join us today as we discuss the following:

The proper tools and flow settings for brazing
How the pressures should be set to SCFM and not PSI
The possibility that geography may contribute to scale
How to flow nitrogen in a practical way

And much more...

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There is More to Check Nov 08, 2016

In this episode, Bryan goes back over the basics and stresses the importance of diagnosing the whole system.

I'll cut to the chase: inspection is NOT overrated. Inspections help you become more familiar with HVAC systems and can help you catch on to minor issues before they spiral out of control. Check air filters, check the charge, check the evaporator coil... does the inspection checklist ever end?

Whether you see crunchy brown contactors or oil on the lines, none of those issues are too small to warrant investigation and repair. Those may not seem worth the hassle, but a leak or low charge can negatively impact the A/C function over time, leaving you with unhappy customers. Checking everything may seem a little over-the-top, but it really is in your customers' best interest. The same goes for mundane procedures like cleaning out drains.

We also have our controversial practice of the day: you don't NEED to remove a slant coil for cleaning all the time. Cleaning it in place is A-okay.

Some of the system procedures I'll discuss include:

Checking the charge completely
Superheat and subcool
Checking the evaporator coil
Inspecting the filter
Looking for wire rubouts
Checking the drain line and drain pan
Checking capacitors and contactors

And much more...

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Replacing a Compressor from Start to Finish Nov 03, 2016

In this podcast episode, Bryan goes over best practices for diagnosing and replacing an A/C or refrigeration compressor.

When testing for a shorted compressor, make sure the compressor is isolated from all of its circuitry. You would see low ohms to ground in a shorted compressor. Do NOT measure from winding to winding or terminal to terminal to diagnose a short.

You may also come across an open winding failure. In the case of an open compressor, the power is going to the compressor, but it’s not doing anything.

Locked compressors also go out on internal overload and draw high amps. Try your best to unlock the compressor but be realistic about the state of compressor health.

Poor compression also indicates a failure. You would typically see low head pressure and high suction pressure with low system capacity.

When replacing the compressor, you’ll want to start off by knowing the type of failure that was diagnosed. Reconfirm the diagnosis. Then, do your acid test and make sure you have a matching capacitor and enough refrigerant to do the job. Know your connection types, compressor model, and warranty status.

Fully recover the old refrigerant charge and remove all existing driers in the system. Braze in the new compressor and pressurize the lines with nitrogen. Bubble-test all new joints and check them thoroughly. Then, pull your vacuum before adding charge by weighing a factory charge into the liquid line.

When you power on the unit, monitor the performance and inspect the unit closely.

Bryan also discusses:

Clarification on flowing nitrogen
Learning theory vs. application
Pulling terminals off
Proper megohmmeter use
“Redneck” test (running the system without the compressor)
Acid and oil testing
Hard start kits and oil migration
Accumulators and acid protocols
Suction line driers
Mufflers
Vacuum pump oil

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The 5 Readings Every Tech Must Know Well Oct 28, 2016

In this episode of HVAC School, Bryan covers the "5 pillars of refrigerant circuit diagnosis" and why they matter. They are:

Superheat
Subcool
Suction pressure
Head pressure
Air temp split (delta T)

These 5 readings give you a holistic idea of the A/C system. Instead of getting hooked on checking only superheat and subcool all the time and dismissing potential diagnoses, you can use these five readings to get an idea of the health of several parts of the system. Making it a priority to take these five readings also promotes open-mindedness, which is perhaps one of the most vital qualities of a diagnostician.

The five pillars will give you the clues to diagnose overcharge or undercharge, a wide variety of restrictions, kinked suction lines, expansion valves failing open, improperly seated pistons, condenser fan issues, and so many more conditions.

Also, regularly check and calibrate your tools. These 5 readings won't be helpful if you aren't constantly making sure your tools are accurate.

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Basic Electrical Theory Oct 12, 2016

In this episode of HVAC School, Bryan talks to his sons about basic electrical theory.

Electrical theory normally requires trigonometry, calculus, and all of those fun maths. However, the basics are so easy that a 12 and 14-year old can figure it out. Electrical theory follows many of the same principles as thermodynamics—however, electrical theory concerns charges rather than heat. Conductors and insulators behave similarly with electrical charges as they do with heat.

Ohm's and Watt's laws establish what volts, amps, power, and resistance, and they explain the relationships between those units. However, magnetism can add a bit of confusion to those equations. We drive motors with inductive loads, making Ohm's law seem invalid, but the magnetism resists itself, which goes unnoticed on ohmmeters. That is untrue of DC motors, and Ohm's and Watt's laws will appear to check out under most circumstances.

An electrical component can fall into three main functional categories: power source, switch, or load. If something doesn't fall into one of those categories, it merely adds resistance. The power source could be a transformer, which provides homes with power from the power company (and goes from a higher voltage to a lower one that our appliances can use). A switch opens/closes or rewires an electrical path, and a load is what does the work.

That's the short of it, but it's still pretty easy.

Join Bryan and his sons as they talk about:

Differential charges
Electromotive force
Ohm's law
Volts, Ohms, Amps, and Watts
Electrical paths
Conductors and insulators
Resistive and inductive loads

And much more...

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Diagnosis, Reconfirmation, Parts Changers, and You Oct 10, 2016

This episode of HVAC School is a Kalos meeting where Bryan talks to his team about an incident where a leak was erroneously detected on the evaporator coil.

The system was three months old, and one of our junior techs diagnosed a leak on the evaporator coil. (What?? That never happens!) So, the customer was quoted for a new evaporator coil. One week later, the charge was low again. The junior technician quoted the customer for more refrigerant charge and leak detection. The customer freaked out.

Unfortunately, there were so many things we could have done to prevent the hassle and frustration for the customer.

All was fine in the end, but we could have gathered more data to perform a more thorough diagnosis, sent out senior technicians to verify the issue, and kept the bigger picture of the service call in mind from the start.

During this meeting, Bryan stresses the importance of:

Reconfirming parts before installing them
Performing a complete diagnosis
Using a micron gauge
Becoming a valuable technician

And much more...

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The Basic Refrigeration Circuit Oct 05, 2016

In this episode of HVAC School, we discuss the entire basic refrigerant/compression refrigeration circuit.

We are in the business of moving heat. Heat refers to motion in the molecules. Temperature is the average velocity of those molecules. Heat needs a temperature differential to move. So, HVAC systems absorb heat when the refrigerant is colder than the ambient temperature. They reject heat when the refrigerant is hotter than the ambient temperature.

Remember the components and their functions in the following order:

Compressor: increases the vapor refrigerant's temperature and pressure.
Discharge line: carries hot, high-pressure, superheated vapor to the condenser.
Condenser: changes the vapor to a liquid.
Liquid line: moves the subcooled (high-pressure) liquid to the metering device.
Metering device: drops the liquid's pressure (creates some flash gas).
Expansion line: leads the low-pressure liquid/vapor mixture to the evaporator.
Evaporator: changes the liquid/vapor mix to a vapor.
Suction line: moves superheated vapor to the compressor.

Note: Heat pumps can shake things up a bit; the suction line becomes the discharge line (and vice versa), and the condenser becomes the evaporator (and vice versa). However, heat pumps have two metering devices and a bi-flow liquid line drier, so the liquid line stays the same. So, watch out for heat pump systems with that tricky little reversing valve.

We also elaborate on some fancy accessories. These include accumulators, discharge line mufflers, receivers, and more.

And we discuss much more...

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Solder Rings, Thermal Imaging and My Grouchy Brother Sep 29, 2016

In this episode of HVAC School, I talk with my brother Nathan... and he whines a lot about cool tools I like.

As you might have guessed, Nathan is in the camp of people who believe that proper training promotes good practices; fancy tools won't make an outstanding tech. Even though I respectfully disagree with him on some things, he has a point. Tools will only be useful if a tech knows how to use them. They should make your life easier, but they shouldn't have much bearing on performance. He doesn't like wasting money or time on tools that probably won't help him. So, he doesn't like solder rings or thermal imaging cameras.

On the other hand, I'm in the "tool nerd" camp. I love new technology and think tools can make us do much better work if we learn how to use them properly. On the job and in my spare time, I enjoy reading up on the latest technology and trying out the newest tools. Missing out on the newest "wow!" tools is a fear of mine. Spending money on a tool that will help me do better, more efficient work is ALWAYS worth it. I think solder rings and thermal imaging cameras are cool and can be put to good use.

We talk about how efficiency, organization, training, job performance, and customer trust relate to tools. We can find some common ground in some areas, even if we have fundamentally different attitudes toward tools.

Oh, and we talk about digital gauges and the jumping spider that lives in Nathan's van.

—Bryan

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The Basics of Moving Heat Sep 22, 2016

In this episode of HVAC School, Bryan talks to some apprentices about basic thermodynamics. That is the fancy scientific way of saying that we're moving heat.

The way we think of "hot" and "cold" is relative to our comfort. However, the scientific concepts of "hot" and "cold" are very different from our relative understandings of those qualities. For instance, there is only ONE value of "cold" in the universe: absolute zero (0 kelvins, -460°F). Any temperature above that contains heat.

Heat and temperature are NOT synonymous. Instead, heat refers to molecular motion, and temperature is an average measurement of molecular motion. Therefore, not all heat results in a temperature change. For example, adding heat to an ice cube at 32°F (0°C) changes the ice cube from a solid to liquid water. The heat added is called latent heat. Heat cannot move unless there is a differential in temperature, and it always moves from an object with more heat to one with less heat. Everything in nature tends towards equilibrium, and heat is no exception. In those cases, heat transfer will theoretically occur until both objects are at the same temperature.

There are three main methods of moving heat: conduction, convection, and radiation. Conduction moves heat when a warmer object touches a cooler one. Convection occurs when heat moves through a fluid. Radiation occurs when heat moves on electromagnetic waves, such as when the sun's heat passes through a window.

Join us as we cover:

Heat & temperature and the difference
Boiling and superheat
Fahrenheit, Celsius, and Kelvin scales
Absolute zero
Molecular motion
Hot and cold
British Thermal Units (BTUs)
Tons of air conditioning (and BTU/ton)
Energy conversions
Pressure and its effect on temperature
Conduction, convection, radiation
How heat transfer works in HVAC/R systems

If you want to learn more about heat transfer, check out this article.

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Why a TXV instead of a TEV?.. or a CSV? Sep 16, 2016

In this episode of HVAC School, Bryan talks to Leslie about the deceptive TXV.

Thermostatic expansion valves, also known as TXVs or TEVs, are metering devices that maintain superheat. They contain an external equalizer. External equalizers give the pressure reading that you would normally take with a suction gauge at the end of the evaporator coil. They supply the closing force to the TXV.

TXVs also contain a sensing bulb. The sensing bulb picks up the superheat on the suction line. When a vapor is superheated, its temperature exceeds its saturation temperature. The superheat value indicates how much the vapor temperature exceeds its saturation temperature. The bulb uses that superheat reading to adjust the TXV's opening force.

System diagnosis can be tricky with TXVs, and you must set the charge by subcool on TXV systems. (Still check the superheat and follow manufacturer instructions, though.) However, TXV issues are pretty straightforward. Many of their issues deal with an undercharged sensing bulb. In those cases, you will notice issues with the opening force that acts on the valve. When replacing a valve, you typically make a new port for the external equalizer. However, getting solder in the tube can block off the closing force of the equalizer. Restrictions are also common issues for TXVs, and improper superheat is an indicator of a TXV restriction.

When we think about the way TXVs manage superheat, "TXV" seems like a misnomer. We might be better off calling them "constant superheat valves" (CSVs).

In addition, Bryan and Leslie discuss: