Tech Tips

Voltage drop is one of those topics we often mention but seldom think about in-depth. From a very basic standpoint, we need to know whether or not the rated voltage is being delivered to the device or appliance while under full load, which is as simple as running the equipment and measuring the voltage at […]

In HVAC, we work with thermocouples for temperature measurement all the time, but we may not understand the difference between a thermocouple and other types of temperature measurement sensors. A thermocouple is just two different types of metal connected at a “junction” that generates a small voltage with a temperature change. Older furnaces would often […]

You probably didn’t expect to find the word “autodidact” on an HVAC education site. You’d probably expect to see it in an SAT prep book or a list of words to say five times fast. What does that word have to do with HVAC? Well, autodidacts are some of the best techs in our trade. […]

I get questions all the time about performing “load calculations” and “rules of thumb” or how to do it properly. This article isn't about load calculation, but the only good answer is to find a quality ACCA-approved Manual J software and get used to using it. You may have heard from others in the field […]

This article was submitted by Genry Garcia of Comfort Dynamics, Inc. It is the final part of his series on zonal pressure diagnostics. Thanks, Genry! Updated 3/4/2022 Picking up where we left off in part 2 of the series, we discussed how a pressure reading from an attached zone indicates only the ratio of the […]

Our industry puts a lot of emphasis on the “AC” (air conditioning) part of HVAC. We specialize in maintaining and servicing a wide variety of simple to complex air distribution systems. But we’re really in the business of comfort—human comfort and health, to be precise. So, just how much does the human body rely on […]

I have been teaching at my local trade school as an HVAC instructor for the past year. It’s been a much different experience than training a technician on the job. Some of the students are already working in the field, and others have never been in an attic or crawl space. But regardless of experience […]

This article was written by Tim De Stasio with Southern Comfort Consulting and Service. It was originally published on his blog, which you can access by clicking THIS link, but he permitted us to republish it on HVAC School as well. Thanks, Tim! It is critical for an HVAC technician to understand airflow and how […]

Let's use a bit of imagination for a minute. Imagine you have two totally identical 3-ton systems. One of them is completely normal, and the other has no fins at all on the evaporator coil. They both have the same charge, airflow, and compressor capacity. What will be different in terms of readings and performance […]