I am working on a standard propane refrigeration system consisting of a screw compressor, horizontal 2 pass condenser, receiver and a chiller. The condenser is not pressure or temperature-controlled and floats with the ambient. There is only a manual louvre control.
My question is about the check valve typically installed downstream of the condenser. It seems common practice to install a check valve after the condenser. The reason for that is to prevent hot gas from entering the receiver through the hot gas condenser bypass going backwards into the condenser. For the longest time, we got told to overcome the cracking pressure of the check valve, a specific elevation upstream of the check valve must be maintained. The common practice is 5-6 ft. This is supposed to provide sufficient head to crack the check open and keep it open.
So we now build a unit on which we cannot maintain even one-foot elevation. We debated what would happen. There is a different opinion and non of them seems consistent or coherent to me. It seems everyone knows something from someone, but nobody understands the whole picture, including me.
Some say the liquid propane will pile back up into the condenser. This will, in return, reduce condensing area, which will increase discharge pressure, which will push the liquid out. Then the cycle starts again. They call it surging.
Others say the compressor will always provide a driving force to crack the check valve open, and no liquid will pile up.
Anyway, I am interested in anyone's experience in that matter. Thanks to all in advance.