How Moisture Moves
Old-timers always used to say that running plumbing and condensate drains wasn't rocket science because “water flows downhill.” While that may be true, water also floats in the air, goes uphill, and forces its way through concrete. Here is a look at some of the ways that water moves that impact building comfort and integrity. […]
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Which Valve Do I Open First?
Testo 557 vacuum gauge and Appion core removal tools shown I've had a change of heart. Back in the early 2000s, during the big construction boom, I did many system startups on residential units for a large company I worked for. When installers ran the line sets prior to startup, they weren't always very careful […]
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Low-Voltage Wiring for Heat Pumps
Time and time again, low-voltage wiring gets the better of HVAC technicians everywhere. Sure, the wires are color-coded, but that doesn’t mean they’re easy to understand. On top of that, schematics sometimes look like ancient tablets written in hieroglyphics or something. But that’s where HVAC School comes in. There is a new 3D animation video […]
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Top Residential A/C Maintenance Tips
Bert recently made a video about his top residential A/C maintenance service tips. He showed some pretty good practices in there, so we’re going to revisit them in this article. Maintenance procedures are vital to any HVAC business, especially those specializing in residential A/C. When we do maintenances, the customers see our faces, and when […]
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Flash Gas
When we say that there is “flash gas” at a particular point in the system, it can either be a bad thing or a good thing, depending on where it is occurring. Flash gas is just another term for boiling. It is perfectly normal (and required) that refrigerant “flashes” or begins boiling directly after the […]
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What If Houses Came with Manuals?
A guide to the “House As A System” approach to understanding comfort, IAQ, durability, and energy consumption issues caused by building air leakage and HVAC-driven pressure imbalances in single-family homes. This article is a collaborative effort between Sam Myers of Retrotec and Genry Garcia of Comfort Dynamics, Inc. Sam and Genry will be giving a […]
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Grit: A Key Trait in the HVAC Trade (and Life)
You may have heard of a Western movie called True Grit. I won’t spoil it for you, but John Wayne joins Kim Darby to hunt down the man who killed Darby’s father and left with the family’s savings. (Wait, you’re telling me there’s a version with Jeff Bridges, Hailee Steinfeld, and Matt Damon? I thought […]
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Understand Dew Point and Absolute Moisture, The Right Side of the Psych Chart
Let's first state the obvious. Most techs are intimidated by psychrometric charts and Mollier diagrams. We JUST ARE. While there are some pretty complicated formulas that back up these diagrams, using them isn't that big of a deal once you understand the different elements and then focus on one at a time. BUT WHY DO YOU […]
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The Ten Duct Commandments (Plus a Few More)
  This article was written by my good friend, Neil Comparetto. He is one of the all-around best dudes in the industry and a guy who practices what he preaches on duct design. Thanks, Neil! These are some fundamentals for designing and installing duct systems that I’ve learned over the years. Included are links to […]
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