Carrier 69NT40-561-399 Operation And Service Manual page 83

AL57 AMBIENT SENSOR (AMBS)
Cause: Invalid Ambient Temperature Sensor (AMBS) reading.
Component
Corrective Action Replace AMBS if defective, refer to TEMPERATURE SENSOR Ser-
AL58 COMPRESSOR HIGH PRESSURE SAFETY (HPS)
Cause: High pressure safety switch remains open for at least one minute.
Component
Corrective Action Replace HPS if defective, refer to Sensor Replacement,
Component
Corrective Action Clean or remove any debris from coils.
AL59 HEATER TERMINATION THERMOSTAT (HTT)
Cause: Heat Termination Thermostat (HTT) is open.
Component
Corrective Action Replace HTT if defective, refer to Sensor Replacement
AL60 DEFROST TEMPERATURE SENSOR (DTS)
Cause: Failure of the Defrost Temperature Sensor (DTS) to open.
Component
Corrective Action Replace the DTS if defective, refer to Sensor Replacement
Ambient Temperature Sensor (AMBS)
Troubleshooting Test the AMBS, refer to Sensor Checkout Procedure
vice Section
High Pressure Switch (HPS)
Troubleshooting Test the HPS; refer to Checking High Pressure Switch,
7.9.1.
7.25.
Refrigeration System
Troubleshooting Check unit for air flow restrictions.
Heat Termination Thermostat (HTT)
Troubleshooting Check for 24 volts at test point TP10, if no voltage at TP10 after unit
has reached set point HTT is open.
7.25.
Defrost Temperature Sensor (DTS)
Troubleshooting Test the DTS; refer to Sensor Checkout Procedure
7.25.
7.25.
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Section 7.25.1.
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Section 7.25.1.
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