What issue leads to sweating of the compressor crankcase?

Sweating of the compressor crankcase is primarily caused by liquid returning to the compressor. When liquid refrigerant enters the crankcase, it can cause the temperature inside the crankcase to drop below the dew point of the air surrounding it. This results in condensation forming on the outside of the crankcase, which manifests as sweating.

This condition can be detrimental because it often indicates that the system is not functioning optimally, leading to efficiency losses and potential mechanical issues. If liquid refrigerant frequently returns to the compressor, it may create further complications, such as slugging, where the compressor is forced to compress liquid instead of gas, which can cause severe damage.

Understanding this mechanism emphasizes the importance of proper refrigerant management and system design, ensuring that gas enters the compressor to avoid unnecessary liquid return that leads to crankcase sweating.