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A2L Refrigerant Sensors: Understanding False Alarms from Off-Gassing
Refrigeration Communication Troubleshooting Using Oscilloscopes
Preventing Heat Illnesses in the BLAZING Summer Heat
What is RS-485 Communication?
A2L Dissipation Boards and Leak Sensors
Oscilloscope Systems and Settings
I’ve Done It This Way for 20 Years – And That’s the Problem
Oscilloscopes 101
Estimating Made Easy with Unity Build
The History of the Thermostat – Short #267
Tech Support Highs and Woes w/ Roman
The Current War – Tesla, Edison & Westinghouse – Short #266
An R-454B Ramble w/ Elliot
Psychrometrics and the Magic Line – Short #265
Learning Hydronics, Boilers and Steam w/ Ray Wohlfarth
How Duct Tape Got Its Name (and Why It Shouldn’t Be on Ducts) – Short #264
The Art of De-Escalation
Legionnaires’ Disease: The Cooling Tower Killer – Halloween Short #263
#hvac
Tech Tips:
As the HVAC industry transitions to refrigerants with lower global warming potential (GWP), A2L refrigerants like R-454B are becoming more common. These refrigerants are classified as “mildly flammable” and require the installation of A2L refrigerant leak detection sensors in many applications to ensure safety. While these sensors are essential for detecting actual refrigerant leaks, HVAC […]
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This tech tip is the final installment in our short series on using oscilloscopes to troubleshoot communicating systems. This time, we're focusing on troubleshooting communication issues in commercial refrigeration systems. Imagine this scenario: you've got a refrigeration system acting up, and the comms network, whether it's LON or MOD-bus, seems a bit flaky. Let me […]
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This tech tip about preventing heat illnesses covers information and resources from the Cleveland Clinic, the U.S. Centers for Disease Control and Prevention (CDC), the U.S. Occupational Safety and Health Administration (OSHA), and the National Oceanic and Atmospheric Administration (NOAA). HVAC School is NOT an official OSHA training resource, and although these safety tips are […]
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This tech tip about RS-485 communication is the third installment in a four-part series about oscilloscopes. It's a primer for the final installment about using an oscilloscope for diagnosis. I owe a special thanks to Jeremy Smith for sharing the information on Danfoss and for sparking my curiosity surrounding this type of communication. Let's talk […]
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The HVAC industry's ongoing shift towards eco-friendly solutions continually introduces new challenges and learning opportunities. A2L refrigerants are at the forefront of this transformation, offering a lower global warming potential (GWP) than many of the refrigerants we’ve been using. A2L refrigerants are also mildly flammable, meaning they require some enhanced safety measures; one of these […]
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This is part two of our four-part series on oscilloscope fundamentals. Special thanks to Andrew Holden for his contributions. In our last tech tip on oscilloscopes, we learned about some safety basics, waveforms, and measurements. We’re going to dive a little deeper into systems and settings on the oscilloscope in this tech tip. Systems are […]
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Every trade has its favorite phrases. One of the most common in HVAC goes something like: “I’ve been doing it this way for 20 years and never had a problem.” When you hear that—or when you catch yourself saying it—it’s worth stopping to think. Usually, what that sentence really means is: “I’ve been doing it […]
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This tech tip is the first in a four-part series on using oscilloscopes. I'd like to give a special thanks to Andrew Holden for his contributions to this particular tech tip. When we want to measure voltage between two points, we reach for a multimeter. A multimeter can tell us the average electrical potential between […]
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Many of you may already know that our HVAC company, Kalos Services, is also a GC. We do a lot of construction projects with HVAC, plumbing, and electrical scopes of work. Estimating is a crucial part of winning those projects, and those of you who work on HVAC for new construction probably already have an […]
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Videos:
Podcasts:
In this short podcast, Bryan gives another history lesson and goes over the history of the thermostat. Before 1883, automatic temperature control simply did not exist; we shoveled fuel into the furnace and opened windows. If a room got too hot in a commercial building, the janitor would go downstairs to choke the draft […]
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In this candid and comprehensive episode, Bryan sits down with Roman to tackle one of the most frustrating yet crucial aspects of the HVAC industry: technical support. What starts as a conversation about their own tech support nightmares quickly evolves into a deep dive examining the entire ecosystem—from manufacturers and distributors to technicians and […]
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In this short podcast episode, Bryan is back for yet another history lesson. This time, the subject is the current war with Tesla, Edison, and Westinghouse. The current war was fought in the late 1800s with lightbulbs, electrocutions, and a World's Fair that dazzled the entire world. Edison didn't necessarily invent the lightbulb, but […]
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In this raw and unfiltered episode, Bryan sits down with Elliot, a senior service tech and newly minted install supervisor, to discuss the realities of working with R-454B refrigerant in the field. What starts as a technical discussion about the new A2L refrigerant quickly evolves into a candid conversation about industry frustrations, manufacturer accountability, […]
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In this short podcast episode, Bryan talks about psychrometrics and the magic line inside a messy-looking chart. The psychrometric chart is a key tool for understanding the relationship between air and water. “Psychrometric” comes from the Greek roots for “cold” and “measurement.” As such, a tool called the psychrometer (with paired wet-bulb and dry-bulb […]
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In this episode of the HVAC School podcast, Bryan sits down with Ray Wohlfarth, a seasoned HVAC contractor and prolific author who has dedicated over 30 years to mastering the art and science of boiler systems. What began as a competitive disadvantage—competitors claiming he knew nothing about boilers—became Ray's driving passion. Through daily reading, […]
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In this short podcast episode, Bryan explains how duct tape got its name and why it shouldn't actually be used on ducts. Duct tape is a versatile home DIY-fix tool, but despite its name, it wasn't initially made to seal ducts at all. In 1943, we were in the thick of World War II, […]
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In this comprehensive discussion, Bryan and Bert tackle one of the most critical yet underdeveloped skills in the trades: conflict resolution and de-escalation. They argue that poor conflict management is one of the primary reasons technicians lose jobs, damage team dynamics, and limit their career advancement. The conversation explores both customer-facing conflicts and internal […]
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In this spooky Halloween short podcast episode, Bryan tells the story of the cooling tower killer: Legionnaires' disease. In the summer of 1976, the nation celebrated its bicentennial anniversary. The American Legion was holding its 58th annual convention at the Bellevue Stratford Hotel in Philadelphia, PA. In the days following the convention, doctors in […]
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