Carrier PrimeLINE 69NT40-561-200 Operation And Service Manual page 84

AL58 COMPRESSOR HIGH PRESSURE SAFETY (HPS)
Cause: High pressure safety switch remains open for at least one minute.
Component
Component
AL59 HEATER TERMINATION THERMOSTAT (HTT)
Cause: Heat Termination Thermostat (HTT) is open.
Component
AL60 DEFROST TEMPERATURE SENSOR (DTS)
Cause: Failure of the Defrost Temperature Sensor (DTS) to open.
Component
AL61 HEATER CURRENT DRAW FAULT
Cause: Improper current draw during heat or defrost mode.
Component
Component
T-362
High Pressure Switch (HPS)
Troubleshooting Test the HPS. Refer to Checking High Pressure Switch,
7.10.1.
Corrective Action Replace HPS if defective. Refer to Sensor Replacement,
7.28.
Refrigeration System
Troubleshooting Check unit for air flow restrictions.
Corrective Action Clean or remove any debris from coils.
Heat Termination Thermostat (HTT)
Troubleshooting Check for 24 volts at test point TP10. If no voltage at TP10 after unit
has reached setpoint, HTT is open.
Corrective Action Replace HTT if defective. Refer to Sensor Replacement
7.28.
Defrost Temperature Sensor (DTS)
Troubleshooting Test the DTS; refer to Sensor Checkout Procedure
Corrective Action Replace the DTS if defective. Refer to Sensor Replacement
7.28.
Heater(s)
Troubleshooting While in heat or defrost mode, check for proper current draw at heat-
er contactors. Refer to Electrical Data
Corrective Action Replace heater(s) if defective. Refer to Evaporator Heater Removal
and Replacement
Contactor
Troubleshooting Check voltage at heater contactor on the heater side.
Corrective Action If no voltage present, replace heater contactor if defective.
Section 7.16.
4–46
Section
Section
Section
Section 7.28.1.
Section
Section 3.3.