Most techs know that you shouldn't fill a recovery tank more than 80% with liquid-based refrigerant. Many know that the WC rating stands for “water capacity.” So, you need to adjust for the density of the actual refrigerant rather than just using 80% of WC. I hope most of you know that the TW marking […]

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 […]

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 […]