Arkansas HVACR NewsMagazine May 2026

HVACR NewsMagazine May 2026

Tech News

of crazy weather that you probably aren't going to keep out of an open suction line. That isn't to say you don't start a compressor just because it looks like it “might rain.” However, I would suggest being prepared with caps or plugs to seal it up quickly if it does start to pour. If it is actively raining, I would also advise against connecting gauges or opening the panels and testing electrical components unless you have a good umbrella or shelter in place. Electrical testing can damage the components as well as be unsafe, and connecting in the rain can lead to moisture contamination.

Setting & Checking Charges in the Rain

Wet Condenser Coil

I live in Central Florida, and while it can get pretty hot in the summer, we also tend to get afternoon thunderstorms that come and go in a flash. I have been connecting gauges, checking charges, and even pulling vacuums in the rain (even under umbrellas or cardboard boxes) for most of my career. Only recently did I stop to think if that was a good idea. I am going to go ahead and make the blanket statement that opening the system or connecting gauges while it is actively raining is just a bad idea. It's not because you are “made of sugar,” as the old -timers and my grandpa might claim. It's actually because even a drop of water in the system can do a lot of damage in the age of POE oil. If you have a good shelter or a large umbrella, you might be OK. In Florida, however, we get these bursts Moisture in the System

You will not be able to test or set a charge with any level of accuracy when the condenser coil is wet. The system pressures will be low, and the subcooling will be high due to the evaporative effect and the superior heat transfer of water over air. (If you want to learn about identifying your proper subcooling temperature, check out this article.)