Carrier VECTOR 1550 Series Operation & Service Manual

62-61753-21 7-36AlarmNO. Steps ALARM / CAUSE CORRECTIVE ACTION54 DEFROST NOT COMPLETE TRIGGER-ON: Defrost cycle did not complete within 45 minutes UNIT CONTROL: Engine and standby operation: alarm only. While this alarm is active, the DefrostTimer will be set to initiate a defrost cycle 90 minutes (1.5 hours) of unit running time after the alarmcomes on. RESET CONDITION: Auto Reset when defrost cycle is started again, or alarm may be manually resetvia keypad or by turning the unit off, then back on again.NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, the activealarm should clear itself (refer to reset condition above). Operate the unit through the appropriate modes to see ifany active alarm occurs. Continue with the steps below as necessary.1 Check For Heat & Sensor Alarmsa. Check the Alarm List for alarms91, 92 &/or 124Alarm conditions must be corrected and the alarmcleared to continue.1 Perform Pretrip Checka. Clear Active Alarm list, then runPretrip & check for any newalarms.Any active alarms must be corrected and cleared be-fore proceeding.2 Check For Defective Defrost Sensor Location/Correct Installationa. Has sensor fallen from location? Must be corrected to continue.3 Check Evaporator Fan Contactora. Check that contactor is not ener-gized and that the contacts are notstuck closed when in defrost.Must de-energize evaporator fan during defrost.4 Check Evaporator Heater Current Drawa. Check Heater amp draw forHTCON1Verify that all three actual amperage readings for eachcomponent are within 10% of each other, and are with-in the values shown in Section 2.11.b. Check Heater amp draw forHTCON2