HVAC School - For Techs, By Techs

Latest Episodes:

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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.

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.

Tubing Insulation Tips - Short #176 Oct 10, 2023

Show notes

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.

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 New HSI Module from White Rodgers Oct 05, 2023

Show notes

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: