The crankcase heater will operate under which condition?

The crankcase heater will operate under which condition?

• A. When the compressor is off
• B. When the compressor is on
• C. When the thermostat is closed
• D. When the blower is running

Answer: (A)

The crankcase heater is used to prevent liquid refrigerant migration and moisture from gathering in the compressor’s crankcase when the system isn’t running. By keeping the crankcase warm during off cycles, any liquid refrigerant inside evaporates before startup, and the oil returns to proper condition, reducing hard-start issues and wear. Because of this, the heater is energized when the compressor is off (idle or shut down) and turned off when the compressor runs to avoid unnecessary energy use and overheating. It isn’t driven by the thermostat being closed or by the blower, which relate to cooling function rather than crankcase protection.

The crankcase heater is used to prevent liquid refrigerant migration and moisture from gathering in the compressor’s crankcase when the system isn’t running. By keeping the crankcase warm during off cycles, any liquid refrigerant inside evaporates before startup, and the oil returns to proper condition, reducing hard-start issues and wear. Because of this, the heater is energized when the compressor is off (idle or shut down) and turned off when the compressor runs to avoid unnecessary energy use and overheating. It isn’t driven by the thermostat being closed or by the blower, which relate to cooling function rather than crankcase protection.