What is the primary purpose of a C.P.R. valve?

The primary purpose of a C.P.R. (Compressor Protection Relay) valve is to prevent low-temperature compressors from overloading. This is crucial in refrigeration and air conditioning systems where compressors operate under varying load conditions. When the temperature in the evaporator falls below a certain point, or if there is a restriction in the system due to a clogged filter or overcharged refrigerant, the compressor can experience an increase in load. The C.P.R. valve helps manage and reduce this load to ensure that the compressor does not become overloaded, which can lead to mechanical failure and system inefficiency.

By regulating the conditions under which the compressor operates, the C.P.R. valve effectively protects the compressor from damage, thus prolonging the life of the system and maintaining optimal performance. This role is critical, particularly in systems with low-temperature applications where the risk of compressor overload is heightened. Other functions like regulating pressure or controlling the flow of refrigerant serve different purposes but are not the primary focus of a C.P.R. valve, which is specifically oriented towards protecting the compressor from overload situations.