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 […]

Today, I ran a service call with another tech where the previous tech had diagnosed an intermittent piston restriction. I read the history beforehand. For the past several years, there were many assorted comfort complaints and a lot of minor charge adjustments in both the summer and winter. It is worth noting here that the […]

When I started in the trade, the idea of flowing nitrogen while brazing was nothing more than the punchline of a joke. Like pulling a vacuum with a micron gauge or proper recovery, it was a wink and nod proposition rather than a real practice. I've had to unlearn many bad habits since those early […]