The temperature of the refrigerant in the evaporator coil can really help us with diagnostics, but we need to know the targets we’re aiming for if we want to get the most out of it as a troubleshooting tool. If we take the return air temperature and subtract 35 degrees from that number, we get […]

Diagram above by Carrier  It's really easy to put a liquid line drier in the proper location, but it's still more commonly installed in the WRONG location. Namely, people install it right at the condensing unit. (OK, it isn't that big of a deal, but I needed some dramatic emphasis.) Installing it at the indoor […]

On an energized, intact circuit, you will read voltage across an OPEN switch when testing with a voltmeter. However, you probably won't read significant voltage across a CLOSED switch. Both sides of a closed switch are electrically identical (or at least very close). Therefore, there should be no movement of electrons between the leads of […]