Crankcase Heater, Checkout And Status / Error Codes - Lennox XC20-036-230-01 Installation And Service Procedure

Crankcase Heater, Checkout and Status / Error Codes

OPERATION:
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 controls the crankcase heater in all units and is located on the liquid line (see figure 2 for
location).
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.
Crankcase Heater Thermostat
CHECKOUT:
Belly-Band Crankcase Heater:
infinite, replace the crankcase heater.
Crankcase Heater Thermostat: As the detected temperature changes, the resistance across the sensor changes. Table
15 on page 69 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 15 on page 69, may be performing as designed. However, if a shorted or open circuit is detected, the
sensor is faulty; the sensor needs to be replaced.
CRANKCASE HEATER (HR1)
CRANKCASE HEATER THERMOSTAT (S40)
Figure 35. Belly-Band Crankcase Heater Thermostat
Using meter set on ohms, check crankcase heater resistance. If resistance is 0 ohms or
Figure 36. Checking Belly-Band Crankcase Heater
Belly-Band Crankcase Heater -
240VAC, 40 Watts
59
XC20