The discharge line exiting the compressor is the hottest part of a refrigeration or air conditioning system. The compressor’s discharge line temperature can be measured by placing an insulated thermistor on the discharge line about 3 inches from the compressor. This discharge line temperature is a measure of the superheated refrigerant’s vapor temperature. Remember, superheated refrigerant refers to a refrigerant vapor that is at a higher temperature than its saturation temperature for a certain pressure. The certain pressure would be the condensing pressure for the high side of the system in this case.
The compressor’s discharge temperature can tell the service technician what is going on inside a refrigeration or air conditioning system. The compressor’s discharge temperature is a reflection of the hottest part of a refrigeration system, and there are limits as to how hot a discharge temperature should be.