HVAC School - For Techs, By Techs

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. 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.

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. 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.

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.

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.

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.

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.

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.

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.

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.

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.