Tech Tips

Suction pressure, head pressure, subcooling, superheat, delta T. Taking all five of these calculations into account on every service call is critical. Even if you must do further diagnostic tests to pinpoint the problem, these five factors are the groundwork before more effective diagnostics can be done. I would also add static pressure as an […]

Travel back in time with me to 2001. I was a young tech, proving my salt out there in the big world of commercial RTU maintenance. One of the steps in the Fall PM list was “test aux heat,” and by golly, that's what I was going to do! I was on the roof of […]

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 […]

I walked into my first real job interview in the HVAC trade. The manager was a guy named Ernie, and he walked me out to the warehouse. Quick warning: guys named Ernie are tough. Don't mess with a dude named Ernie. He walked up to a box, snatched a pen out of his shirt pocket, […]