Tech Tips

If you work in large commercial offices or mixed-use buildings, you almost certainly work with VAV systems regularly. If you aren’t familiar with VAV, this is a quick intro to the basics so that they won’t seem so overwhelming. VAV stands for variable air volume; this means that the AHU (air handling unit) can vary […]

I was about 13 years old the first time I bent EMT with my uncle. We were doing a renovation at a church; watching him bend EMT and then getting to do it MYSELF was a truly religious experience. There are a few things in the trade where workmanship really comes into play, such as […]

This quick tip was written by Daniel Andersen in the HVAC School Group. Daniel was one of my early encouragements to make the podcast, even though he refuses to come on himself. Thanks, Daniel! ERV – What is it?  An energy recovery ventilator allows fresh air from outside to be introduced into the conditioned space […]

Because the name of the website is HVAC School, I get a lot of people who assume we either: A) Have a physical location B) Sell online courses You are probably aware by now that we do neither of those things. We are a free learning resource for anyone looking to improve their professional skills […]

  You’ve probably heard the famous last words, “Dude, watch this,” before a concussion, burn, shock, broken bones, or some other bodily harm. This phrase has become synonymous with young guys doing something dumb to impress their friends. Technicians have two common phrases that may not lead to bodily harm (although sometimes they might), and […]

I got in one of these tiny torches the other day to experiment with brazing aluminum in tight spots, and one of the techs walked in and asked, “What type of torch is that?” I answered, “It’s oxy/acetylene.” He picked it up and looked at it a bit, then asked, “Does that get hot enough […]

  We’ve all heard about glide, but what is it really, and how does it affect our system? Glide, or temperature glide, is the difference between the bubble point and the dew point of the zeotropic refrigerant mixture. Well, that wasn’t very helpful, was it? All we did was introduce new terms without defining them, […]

Every year when outdoor temperatures rise, there is a rash of news stories and articles about air conditioning. We had an early heatwave this year, and many people have come out and referred to the idea of a rule of thumb of what temperature you can achieve indoors based on the outdoor temperature; most commonly […]

Have you ever seen a low-voltage transformer like the one shown above? It has multiple input (primary) taps for a good reason. It is common to find three-phase and single-phase equipment rated to operate on both 240v and 208v power. That is because three-phase power can either be 208v leg to leg when the building […]