What is the function of the crankcase heater in a refrigeration system?

The function of the crankcase heater in a refrigeration system is primarily to prevent compressor flooding. When a refrigeration system is off, refrigerant can migrate into the compressor's crankcase from the evaporator or other parts of the system. In colder conditions, this refrigerant could remain in a liquid state within the crankcase. If the compressor is started under these conditions, the liquid refrigerant can cause hydraulic damage or "flooding," severely impacting compressor efficiency and potentially causing failure.

The crankcase heater warms the compressor oil and the crankcase, helping to ensure that any refrigerant that might have migrated into the crankcase evaporates before the compressor is powered on. This process minimizes the risk of liquid refrigerant entering the compressor, thus protecting it and maintaining system reliability.

While other options presented might seem related, they do not accurately reflect the primary role of the crankcase heater within the system's operation and maintenance.