Tech Tips

Our company recently had an incident where someone was operating a scissor lift and hit a fire sprinkler with it. The sprinkler activated, and the area flooded. Fire sprinklers activating, unfortunately, isn’t that uncommon in the electrical, construction, and HVAC trades, but it’s preventable with proper training and attention to detail. Those of you who […]

Being in an industry that requires a lot of travel—local or regional—can be a great thing for people who enjoy driving. It also comes with several more risks and opportunities for roadway accidents than someone who just has a round-trip commute to a single location every day. We’re all aware of the issues of texting behind […]

A few times in the past, we’ve heard the phrase “the house is the biggest duct” because of the way air moves through it. Well, we can take it a step further and see that there are similarities that go just beyond air movement. A building has several layers to keep things like moisture, heat, and […]

Delta T is the difference in temperature between two points of the same medium. It is commonly used by scientists and engineers to analyze the amount of heat transfer in a system. In general HVAC terms, it is the measurable change in temperature between an air input and air output. However, it could also be […]

DISCLAIMER: HVAC School is NOT an official OSHA safety training resource! Although we provide safety tips in good faith, neither this tech tip about the hazards of working at heights nor any other training on our website is a substitute for safety training from an authorized OSHA training source. Many things may deter people from […]

You may have noticed that 3/8″ liquid lines are generally the norm in equipment 5 tons and under. We went to a job where the system had a 1/2″ liquid line, and it got me thinking about liquid line sizing and the ramifications of going larger or smaller on the liquid line. Liquid Line Basics […]

In residential, most techs and installers size the suction (vapor) and liquid lines to the stubs on the equipment. In larger built-up systems, sizing the suction and liquid lines is rarely the responsibility of the technician. But what happens if we show up to a job where the lines cannot be (reasonably) replaced because the […]

Air changes per hour (ACH/ACPH) simply describes how many times the total quantity of air in a room (or structure) is completely replaced per hour. If you have a 10'x10'x10′ room, the room contains 1000 cubic feet of air. If the supply and return to the room provide a balanced 100 CFM (cubic feet per […]

This tech tip about non-invasive testing comes from a post in the HVAC School Facebook group by Ed Janowiak. Ed is the Manager of HVAC Design Education at ACCA, a longtime friend of HVAC School, and an educator who does a lot of great work for the industry. Thanks, Ed! This past Thursday, I taught […]