What is the purpose of a crankcase heater?

The purpose of a crankcase heater is primarily to prevent liquid refrigerant from accumulating in the compressor. When a refrigeration or air conditioning system is turned off, particularly in low ambient temperatures, some refrigerant can condense and collect in the compressor's crankcase. If this liquid refrigerant is allowed to remain in the compressor during startup, it can lead to damage or failure due to hydraulic lock, where the compressor cannot compress the liquid refrigerant effectively.

By using a crankcase heater, heat is applied to the compressor's oil pan, warming the accumulated refrigerant and facilitating its transition back into a gas, thereby preventing liquid from entering the compression chamber at startup. This ensures that the compressor is operating with vapor and helps maintain the longevity and reliability of the unit.

While other options may relate to different components or functions within the system, they do not accurately capture the specific role of the crankcase heater in protecting the compressor from damage due to liquid refrigerant accumulation.