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31-5000751 Rev. 0
Crankcase Heater, Checkout and Status / Error Codes
OPERATION:
Crankcase Heater (HR1)
Compressors in all units are equipped with a 40 watt belly-band type crankcase heater. The heater prevents liquid from
accumulating in the compressor. The heater is controlled by the crankcase heater thermostat.
Crankcase Heater Thermostat (S40)
Crankcase heater thermostat S40 controls the crankcase heater in all units and is located on the liquid line (see Figure 2
and Figure 3 for locations).
1.
When liquid line temperature drops below 50°F the thermostat closes which results in the heater being energized.
2.
When liquid line temperature rises above 70°F the thermostat opens which results in the heater being de-energized.
Figure 31. Belly-Band Crankcase Heater Thermostat
Belly-Band Crankcase Heater -
240VAC, 40 Watts
Crankcase Heater Thermostat
CHECKOUT:
Belly-Band Crankcase Heater:
Using meter set on ohms, check crankcase heater resistance. If resistance is 0 ohms or
infinite, replace the crankcase heater.
Figure 32. Checking Belly-Band Crankcase Heater
Crankcase Heater Thermostat:
As the detected temperature changes, the resistance across the sensor changes. Table
22 shows how the resistance varies as the temperature changes for this sensor.
NOTE:
When checking the ohms across a sensor, be aware that a sensor showing a resistance value that is not within the
range shown in Table 22, may be performing as designed. However, if a shorted or open circuit is detected, the sensor is
faulty; the sensor needs to be replaced.