What does a crankcase heater help to prevent in a refrigeration system?

A crankcase heater is designed to prevent liquid refrigerant from entering the oil in the compressor crankcase. When a refrigeration system is off, the refrigerant can migrate into the compressor oil, especially in low-temperature applications. This liquid refrigerant can dilute the oil, leading to inadequate lubrication when the system starts up.

When the compressor is not running, the crankcase heater warms the crankcase and the oil inside, creating a condition where the refrigerant stays in a gaseous state rather than condensing into a liquid and mixing with the oil. This ensures that, upon startup, the compressor has sufficient lubrication without the drawbacks of liquid refrigerant being present in the oil, preventing potential compressor damage and ensuring efficient operation.

Options relating to pressure build-up, excessive vapor expansion, and heat loss through insulation are not directly affected by the function of the crankcase heater, making them less relevant in this context. Therefore, the primary role of a crankcase heater is to keep liquid refrigerant out of the oil, making it crucial for maintaining the integrity and efficiency of the refrigeration system.