Carrier 69NT40-561-300, Operation And Service Manual

Page: 83 / 174

4–49 T-365
AL57 AMBIENT SENSOR (AMBS)
Cause: Invalid Ambient Temperature Sensor (AMBS) reading.
Component Ambient Temperature Sensor (AMBS)
Troubleshooting Test the AMBS, refer to Sensor Checkout Procedure Section 7.25.1 .
Corrective Action Replace AMBS if defective, refer to TEMPERATURE SENSOR Ser-
vice
Section 7.25 .
AL58 COMPRESSOR HIGH PRESSURE SAFETY (HPS)
Cause: High pressure safety switch remains open for at least one minute.
Component High Pressure Switch (HPS)
Troubleshooting Test the HPS; refer to Checking High Pressure Switch, Section
7.9.1 .
Corrective Action Replace HPS if defective, refer to Sensor Replacement, Section
7.25 .
Component Refrigeration System
Troubleshooting Check unit for air flow restrictions.
Corrective Action Clean or remove any debris from coils.
AL59 HEATER TERMINATION THERMOSTAT (HTT)
Cause: Heat Termination Thermostat (HTT) is open.
Component 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.
Corrective Action Replace HTT if defective, refer to Sensor Replacement Section
7.25 .
AL60 DEFROST TEMPERATURE SENSOR (DTS)
Cause: Failure of the Defrost Temperature Sensor (DTS) to open.
Component Defrost Temperature Sensor (DTS)
Troubleshooting Test the DTS; refer to Sensor Checkout Procedure Section 7.25.1 .
Corrective Action Replace the DTS if defective, refer to Sensor Replacement Section
7.25 .