A refrigeration system with an overcharge of refrigerant is an issue that almost all technicians have come across at some point in their careers.

Bob and Tim were at the house of a customer who said that her air conditioning unit did not cool well in the hot weather three days ago. She said the unit actually froze up and had ice on the outdoor portion of the unit on the big line. She shut the unit off and called for service.

The next time you’re faced with a choice of whether you should take some extra time and additional measurements, do the right thing. Take the time to do it right and find the true problem the first time.

Thinking back on my attempt as a young man to charge my car’s air conditioner, I was stunned to see a commercial on TV the other day for A/C PRO, a do-it-yourself a/c recharge kit for cars and trucks. I went to the website and, sure enough, they’re selling recharging canisters of R-134a for do-it-yourselfers.

John Tomczyk, Professor of HVACR at Ferris State University and co-author of Refrigeration and Air Conditioning Technology, discusses refrigerant undercharge.

Those small-diameter coils — with names like MicroGroove, microchannel, and micro-multichannel — have gained a beachhead in residential heating and air conditioning, and are advancing in commercial HVAC, with refrigeration on the horizon.

Designed for air conditioners, the R-410A recharge kit’s disposable, 1.8-pound R-410A cylinder is composed of a reusable gauge, ¼-SAE outlet, and shutoff valve/adapter 5⁄16 inch.