I know I'm gonna get some eye-rolling here, but it needs to be said. When we teach electricity to new techs, we use a lot of “water” metaphors. We talk about volts like PSI, amps like flow, and watts like GPM (speaking of GPM in HVAC, check out our article on hydronics HERE). Even the […]

This article is written by Sal Hamidi, founder of Productsbypros.com, an innovative manufacturers representative agency that promotes great HVAC/R products through training and media. You can reach Sal at Sal@productsbypros.com.   If we are going to discuss vacuum pump oil, it's important to understand what it is first. Most HVAC application vacuum pumps are rotary […]

Why is it called single-phase 240 when there are two opposing phases (or legs)? I wondered why we called two 120v opposing legs “single-phase 240” for years. Then someone pointed out to me that a typical “single-phase” pole transformer only has one power leg entering and two coming out. That freaked me out. How can […]