Tech Tips

The easy answer is 32v. Class dismissed. I’m only joking, of course. Finding the difference between 208 and 240v power supplies may sound quite simple, but there are some pretty sharp fundamental differences. Apart from the obvious differences in overall voltage, 208 and 240v power supplies use the electrical company’s power differently. The motors also […]

Recommended Duct Velocities (FPM) Duct Type Residential Commercial / Institutional Industrial Main Ducts 700 – 900 1000 – 1300 1200 – 1800 Branch Ducts 500 – 700 600 – 900 800 – 1000   As service technicians, we are often expected to understand a bit about design to diagnose a problem fully. Duct velocity has many […]

If you don’t have a gas furnace or fireplace in your home, your unit’s reversing valve is probably your best friend during the winter months.  As their name suggests, reversing valves reverse the refrigerant flow to send the hot, compressed vapor to the indoor coil instead of the outdoor coil. The system releases heat into […]

Recovering refrigerant sounds like an easy task at first, especially with digital recovery machines and large hoses at our disposal. Unfortunately, we all know that filling the tanks is more complicated than it seems.  If you want to recover refrigerant and store it in a tank safely, you’re going to have to do some math. […]

This article deals heavily with entropy. Entropy is not a simple topic, so we highly recommend checking out HVAC School’s Entropy in Refrigeration and Air Conditioning for some background information. Describing isentropic compression is a daunting endeavor. We all recognize the term compression, and I’m sure most of us can deduce that isentropic has something […]

You may have heard about “swamp coolers” before. Surprisingly, we don’t see too many of them in Florida—even though the state is famous for its swamps.  Contrary to their name, swamp coolers are common in arid (dry) climates. They’re also called evaporative coolers because they use the evaporation process to cool the air.  This article […]

This article is based on the January 28th episode of the HVAC School Podcast: “How to Value Engineer Better w/ Alex Meaney,” Which you can listen to HERE. Simply put, value engineering is the process of finding ways to cut costs out of a project WITHOUT creating quality issues. As Alex stated, 2+2 doesn’t always […]

This article was written by Ryan Findley. Thanks, Ryan! This article will be geared toward HVAC techs who are new to mini-splits. As the mini-split market continues to grow, technicians face more and more challenges with these systems. The most critical challenges would be insufficient training and the lack of proper tools to work on […]

This article was inspired by an email we received from a viewer of our HVAC School YouTube channel, Jim Holbrook. Thank you, Jim! Disclaimer: This article is written to help educate you and hopefully save lives. We are NOT an authority on the topic. OSHA, as well as company best practices and risk assessments, should […]