What is the main function of a crankcase heater?

The main function of a crankcase heater is to prevent refrigerant migration to the compressor crankcase during the off-cycle. When a refrigeration system is turned off, refrigerant can migrate from the evaporator to the compressor’s crankcase due to gravity and pressure differentials. If refrigerant collects in the crankcase, it can lead to compressor damage upon startup, as the compressor is not designed to operate with liquid refrigerant inside it.

The crankcase heater works by warming the compressor, maintaining its temperature above the refrigerant’s saturation temperature, which keeps the refrigerant vaporized and prevents any liquid accumulation. This is particularly important during periods of low ambient temperatures or extended off cycles, ensuring that when the compressor starts, it does so without the risk of liquid slugging, allowing it to function correctly and prolonging its lifespan.

Keeping the refrigerant vaporized helps ensure efficient operation of the refrigeration system, preventing potential mechanical failures and ensuring the compressor operates as intended when the system cycles back on.