HVAC School - For Techs, By Techs

In this short podcast episode, Bryan talks about electric heat and whether your service or maintenance procedure actually allows you to test every heat strip. In our climate, we use electric heat as auxiliary heat (as opposed to a furnace in a dual-fuel setup). There is also some information about maintenance procedures, blower interlocks and relays, and math to determine amperage. If you put the thermostat in heat and the blower runs, you only prove that the heat pump is heating; it doesn't tell you which electrical circuit is heating, or whether the auxiliary heat is producing heat at all. You can't assume that the last tech left you the correct kit with everything wired up and that it has been wired properly with the correct wire size. Electric heaters in heat pumps usually turn on with a W call from the thermostat or the defrost board. Sometimes, there is a high-voltage interlock with a relay that runs the blower with the electric heat but not the other way around. Older heat strips may also have heat sequencers, which follow a specific sequence and stage on or off over time. We test heat strips by forcing a call for heat, waiting as long as needed, measuring the amperage to make sure it matches the heat kit, making sure the blower comes on, and verifying that the call for heat ends as it's supposed to. Temperature rise may also be a useful measurement. If a similar procedure is part of your fall maintenance, let the customer know that there may be an odor, and you may clean dirty heat strips with compressed air or an electrical contact cleaner. The key takeaway is to make sure the amperage is correct and that the circuit's wiring and relays can safely carry the current. Don't assume that everything is correct when you work on a unit for the first time. This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, Copeland, and Santa Fe Dehumidifiers. Resources An Electric Heat Mistake (Tech Tip) Electric Heat & Blower Interlock (Tech Tip) Electric Heat Troubleshooting, Service, and Math Class (Video) Basics of Testing Electric Heat Kits w/ Bert (Video) Inside a Sequencer (Video) Sequencer Facts - They Aren't All the Same (Video) Relays, Sequencers, Transformers, and Bad Metaphors (Podcast) HVAC School calculators Submit a podcast question Learn about the GRIT Foundation Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this live stream, co-branded with Kalos, Bryan Orr sits down with Kalos refrigeration team members Christian Maitland and Alex Orr to talk about the realities of working on market refrigeration systems. The conversation starts with the rapid arrival of new equipment in grocery stores, especially transcritical CO2 racks, and why even well-trained techs are running into problems nobody has seen before. Because these are engineered, built-up systems rather than mass-produced units, the first real stress test often happens in the field, during installation and startup. The group digs into where those problems actually come from. Some are classic installation errors, like skipping nitrogen purges while brazing, leaving burrs in pipe, or forgetting that ACR copper plugs sit on the inside of the pipe. Others trace back to the manufacturer: sensors landed on the wrong terminals, swapped sensors that left a condenser fan unable to run, controllers that overheat and reset, and programming that was tested in a different climate than the one the equipment ends up in. With multiple manufacturers supplying the rack, controller, and condenser, nobody owns the interface between the pieces, so startup techs end up tuning parameters store by store. Bryan, Christian, and Alex also walk through the root cause process they rely on, which is essentially the scientific method: observe the complaint, form a hypothesis, test it, and then keep digging until you know why it happened and can confirm the fix on the next job. They discuss store dew point and airflow as the most common causes of iced-up and sweating cases, a humbling misdiagnosis involving a transducer and a redundant controller, and the pain of 19-week lead times and wrong parts arriving seven times in a row. The episode closes with practical advice for techs. Walk into every store and use your senses, check behind your install team, pull your vacuums, and document conversations with customers when expectations don't match the equipment specs. Christian encourages techs to share what they learn with peers, Alex reminds listeners that solving ridiculous problems is the job and a chance to be the hero, and Chad's late addition is a reminder that equipment should be designed for worst-case conditions rather than a design day. Topics Covered Transcritical CO2 coming to the U.S. market, and why it behaves differently above roughly 86°F Challenges of high ambient temperature and humidity in Florida, including limits of adiabatic cooling Controllers that overheat and reset, and how quickly a CO2 system can lose its charge when that happens Safety and mindset for techs moving from traditional DX to high-pressure CO2 systems Why built-up systems get their first real field test at installation and startup Clean piping practices: nitrogen purging, burrs, carbon buildup, and tiny orifices in ejectors and microchannel coils The pipe plug in the EPR story and other lessons from early grocery work Manufacturer errors caught at startup, including miswired harnesses and swapped sensors Interconnected controls from different manufacturers and the need for site-specific programming Setting customer expectations on case placement, shelving, and spec limits, and documenting those conversations Store dew point, dehumidifiers, and ceiling fans disrupting open-case air curtains Using building science tools like smoke pens and vane anemometers on refrigeration cases The root cause process: observe, hypothesize, test, find the real cause, and verify the fix A transducer misdiagnosis and why to rule out everything before ordering long-lead-time parts Parts lead times, wrong parts, and the hidden labor cost of learning new equipment alongside manufacturers Commissioning during live-store case swaps, and the gap in manufacturer training for new equipment What techs look for on a first walkthrough, plus startup checks like line sizing, case assembly, and pulling vacuums Gaps in tools, such as digital gauges built for transcritical systems Closing takeaways: share knowledge with peers, own the problem, and design equipment for worst-case conditions This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, Copeland, Santa Fe Dehumidifiers, and TruTech Tools. Resources Matthew Taylor's Rack Refrigeration Series (YouTube playlist) Intro to CO2 w/ Don Gillis (podcast) CO2 Refrigeration Rack Overview (video) Ramping Your Team Up for CO2 (tech tip) How Do You Ramp Up Your Team to Effectively Service and Support CO2 Applications? (podcast) HVAC School calculators Submit a podcast question Learn about the GRIT Foundation Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this short podcast episode, Bryan covers why and how to test heat pump defrost during maintenance. Heat pumps need defrost because the outdoor coil absorbs heat in heating mode. Moisture collects and freezes on the coil during this process, and the rate at which it happens depends on the temperature and the amount of moisture in the outdoor air. Frost interferes with heat transfer and airflow and must be defrosted; the reversing valve shifts and auxiliary heat turns on. Before testing, identify the equipment brand and model, defrost control, and the defrost type (time & temperature or demand defrost); you may have a thermostat (open/close switch) or thermistor, and those have different operating and testing considerations. Some controls also allow you to accelerate timing. Forcing defrost according to the manufacturer's literature will let you discover whether the command sequence works, but it may not tell you whether the sensors are working. Common visual checks can also help you resolve defrost issues dealing with sensors, base pan heaters, and poor airflow. The key takeaway is to pay close attention to the defrost sequence, conditions, defrost logic, sensor type, and your own spidey senses when testing or diagnosing defrost. This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, Filtrete, and the 2027 AHR Expo. Resources Learn Everything About Heat Pump Defrost (video) HVAC Defrost Troubleshooting | Timers, Sensors, and Boards (video) Heat Pump Defrost Cycle & Heat Strip Wiring Safety | HVAC Heating Season Preparation (video) How to Test Heat Pump Defrost and How Defrost Works (video) Upgrading Time & Temperature Defrost with Demand Defrost for Heat Pumps (tech tip) Heat Pump Defrost Troubleshooting Tips (tech tip) Coil Temp Sensors: Thermostats vs. Thermistors (tech tip) HVAC School calculators Submit a podcast question Learn about the GRIT Foundation Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this live stream episode, Bryan sits down with Tony Gonzalez, who has spent more than 25 years at Fieldpiece and now leads the company's training department. Tony started out packing boxes in the warehouse straight out of high school, and the two longtime industry veterans use his experience to dig into why culture matters so much when you are building a business that lasts. As Bryan puts it, culture may be talked about in HVACR, but it is true everywhere. Tony walks through TURTL, the five core values that anchor Fieldpiece's culture: Tribe, Upfront homework, Right stuff, Trust, and Lean. The missing "E" is intentional, since it reminds everyone to leave their ego at the door. He explains why values can't be purely aspirational, and how Fieldpiece keeps them alive through recognition, one-on-ones, and development reviews. Bryan shares how the same ideas show up at Kalos, including the phrase "professional pride, personal humility." The conversation then turns to leadership, which both guests agree is where culture is won or lost. They discuss why your culture is defined by the worst behavior you tolerate, why people stay at a company, and why curiosity should come before judgment. Tony describes the "bank account" of care that makes hard conversations productive, along with the Radical Candor idea of avoiding ruinous empathy. Bryan adds that clarity is kindness and that small problems should be dealt with before they become mountains. They close by looking at team building, using Bryan's flight crew analogy and the "right people on the bus" idea from Good to Great. Every role matters, leaders shouldn't only hire people like themselves, and snap judgments can make you overlook great talent. Bryan wraps up with a few of his leadership commitments, and Tony's final advice is to start documenting what matters to your organization, live it consistently, and give yourself grace on the leadership journey. Topics Covered: Tony's 25-year career at Fieldpiece, from warehouse to head of training The TURTL core values and why "Turtle" has no E Keeping core values visible through quarterly recognition, one-on-ones, and development reviews Leaders as culture carriers, and how culture shows up when things go wrong Defining culture as a social operating system and the worst behavior you tolerate Professional pride and personal humility, and leaders who celebrate their team's success Why people stay: growth, recognition, fair compensation, and connection to the mission Curiosity before judgment, root cause thinking, and celebrating failure Making "deposits" of care so difficult conversations go well Radical Candor, ruinous empathy, and clarity is kindness Handling bad news and building a safe environment for people to speak up Building a flight crew: hiring for attitude, valuing different strengths, and avoiding the horns effect The weakest link in the chain and treating every role as equally important Book recommendations: Good to Great, The Power of Company Culture by Chris Dyer, and Delivering Happiness by Tony Hsieh Bryan's leadership commitments: truth over comfort, open doors with no gatekeeping, and people over plans Key takeaway: leaders must live the culture, give yourself grace, and define your North Star. This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, Copeland, Santa Fe Dehumidifiers, and TruTech Tools. Resources Good to Great by Jim Collins (book) The Power of Company Culture by Chris Dyer (book) Delivering Happiness by Tony Hsieh (book) HVAC School calculators Submit a podcast question Learn about the GRIT Foundation Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this short podcast episode, Bryan discusses electrical connections and whether tighter is better (or if a connection is tight enough to fail). Torque is a turning effect; force is applied at a distance from the screw's center, and that force creates pressure at the connection. A quarter-turn doesn't tell us how much force we have applied. You may notice a tight screw with other signs of a poor connection, like discoloration; tightening the connection may not help. At a connection, we want very little resistance to current flow, and we get increased resistance and heat where we don't want it when connections are poor; according to Watt's law, when the resistance stays the same, doubling the current creates four times the heating power. However, temperature alone doesn't tell you the cause; thermal imaging is useful evidence, but we need operating conditions and current measurements, too. The key takeaway is that tightening the connection as much as possible may do more harm than good; having a torque screwdriver and using it can help. When making new connections, use the torque screwdriver to torque to the proper specs right out of the gate. We must also consider wire sizing, wire placement, exposed conductors, and unacceptable double lugging. We must also be mindful of ferrules, including proper selection and crimping. Make all adjustments safely (without voltage), and if you do not have the manufacturer's data immediately available, look it up. Eventually, you will get an idea of what "good" looks like. Remember: tighter doesn't necessarily mean better. This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, Filtrete, and the 2027 AHR Expo. Resources Tightening Electrical Threaded Terminal Connections (tech tip) HVAC School calculators Submit a podcast question Learn about the GRIT Foundation Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.