When you ask many people nowadays how to check the charge on a heat pump during low outdoor temps, they will say that you need to “weigh in and weigh out” the charge. While this may be an effective method, it isn't always practical. Now, if you are making a refrigerant circuit repair, weighing out […]

DISCLAIMER: HVAC School is NOT an official OSHA safety training resource! Although we provide safety tips in good faith, our website is not a substitute for safety training from an authorized OSHA training source. Although we primarily work with our hands, our eyes are one of our most valuable assets in the industry. After all, […]

I was listening to someone talk about air relative humidity the other day while looking at a psychrometric chart, and he commented that the chart ends down at freezing (32°F) because “all the water freezes out of the air at that point.” I think I made this Jed Clampett face: The psychrometric chart is designed […]