HVAC School - For Techs, By Techs

Latest Episodes:

Troubleshooting The Modern ECM Feb 16, 2023

Show notes

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.

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 for the Future w/ Clifton & ESCO Feb 09, 2023

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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

Show notes

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: