The most common diagnosis with expansion valves is failed closed or restricted, resulting in underfeeding of the evaporator. The symptoms are low suction, normal subcooling, and high superheat when a TXV fails “shut,” but there are some other issues to watch for that can actually result in overfeeding the coil. Schrader in the Port The […]

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 […]

Jacques Charles was a French physicist (and a real looker based on that photo) born in 1746. Little is known about his educational and family background, but he began his career as a clerk at the Ministry of Finance in Paris. After a short time as a financial clerk, he began focusing on science. The […]