HVAC School - For Techs, By Techs cover art

HVAC School - For Techs, By Techs

HVAC School - For Techs, By Techs

By: Bryan Orr
Listen for free

This Season's Biggest Deal | £0.99/mo for 3 months + £10 Audible bonus

£5.99/mo after 3 months - terms apply. Cancel monthly
Summary
 HVAC School is the ever growing online source for real training topics for technicians in the Air-conditioning, Heating and Ventilation Fields. In the podcast, we will share recorded training, tech ride alongs, share challenging diagnostic scenarios. All to help make the industry, your company, and your truck a better place to be. Career Success Economics Personal Development Personal Success
Episodes
  • Did You Actually Test Every Heat Strip - Short #311

    Did You Actually Test Every Heat Strip - Short #311
    Nov 10 2026

    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.
    Show More Show Less
    15 mins
  • Uncovering the Root Causes of Commercial Refrigeration Failures

    Uncovering the Root Causes of Commercial Refrigeration Failures
    Nov 5 2026
    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°FChallenges of high ambient temperature and humidity in Florida, including limits of adiabatic coolingControllers that overheat and reset, and how quickly a CO2 system can lose its charge when that happensSafety and mindset for techs moving from traditional DX to high-pressure CO2 systemsWhy built-up systems get their first real field test at installation and startupClean piping practices: nitrogen purging, burrs, carbon buildup, and tiny orifices in ejectors and microchannel coilsThe pipe plug in the EPR story and other lessons from early grocery workManufacturer errors caught at startup, including miswired harnesses and swapped sensorsInterconnected controls from different manufacturers and the need for site-specific programmingSetting customer expectations on case placement, shelving, and spec limits, and documenting those conversationsStore dew point, dehumidifiers, and ceiling fans disrupting open-case air curtainsUsing building science tools like smoke pens and vane anemometers on refrigeration casesThe root cause process: observe, hypothesize, test, find the real cause, and verify the fixA transducer misdiagnosis and why to rule out everything before ordering long-lead-time partsParts lead times, wrong parts, and the hidden labor cost of learning new equipment alongside manufacturersCommissioning during live-store case swaps, and the gap in manufacturer training for new equipmentWhat techs look for on a first walkthrough, plus startup checks like line sizing, case assembly, and pulling vacuumsGaps in tools, such as digital gauges built for transcritical systemsClosing 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 calculatorsSubmit a podcast questionLearn about the GRIT Foundation Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.
    Show More Show Less
    1 hr and 1 min
  • Why and How to Test Heat Pump Defrost - Short #310

    Why and How to Test Heat Pump Defrost - Short #310
    Nov 3 2026

    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.
    Show More Show Less
    12 mins
adbl_web_anon_alc_button_suppression_t1
No reviews yet