If you are used to simple, straight cool split systems, you know that the low voltage to the outdoor unit is usually VERY simple with just a Y (contactor power) and a C (common) connected to the outdoor unit in many cases. When the condensing unit controls are strictly two-wire low voltage, there is no […]

A 40VA transformer is rated for 40 VA or volt-amps on the secondary. For a typical 24 volt secondary, this is simply using Watt's law to calculate amperage. (For more information on Watt's or Ohm's laws, please check out this article HERE.) 40 ÷ 24 = 1.666666 ∞ (round up to 1.67 already) So, you […]

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 […]