Carrier PrimeLINE - Abnormal Pressures; Abnormal Noise or Vibrations

T-362 6–4
Will not initiate defrost
manually
Manual defrost switch defective Replace
Keypad is defective Replace
Defrost temperature sensor open Replace
Initiates but relay (DR) drops
out
Low line voltage Section 3.3
Initiates but does not defrost
Heater contactor or coil defective Replace
Heater(s) burned out Section 7.16
Frequent defrost Wet load Normal
6.7 Abnormal Pressures
High discharge pressure
Condenser coil dirty Section 7.11.1
Condenser fan rotating backwards Section 7.12
Condenser fan inoperative Section 7.12
Refrigerant overcharge or non-condensibles Section 7.3
Discharge service valve partially closed Open
Electronic expansion valve (EEV) control malfunction Replace
Low suction pressure
Incorrect software and/or controller configuration Check
Failed suction pressure transducer (SPT) or
evaporator pressure transducer (EPT)
Replace
Suction service valve partially closed\ Open
Filter drier partially plugged Section 7.14
Low refrigerant charge Section 7.3
No evaporator air flow or restricted air flow Section 7.15
Excessive frost on evaporator coil Section 6.6
Evaporator fan(s) rotating backwards Section 7.17.3
EEV control malfunction Replace
Failed digital unloader valve (DUV) Replace
Suction and discharge
pressures tend to equalize
when unit is operating
Compressor operating in reverse Section 6.15
Compressor cycling/stopped Check
Failed digital unloader valve (DUV) Replace
6.8 Abnormal Noise or Vibrations
Compressor
Compressor start up after an extended shutdown Normal
Brief chattering when manually shut down
Compressor operating in reverse Section 6.15
Loose mounting bolts or worn resilient mounts Tighten/Replace
Loose upper mounting Section 7.9.1
Loose slugging Section 7.15
Condenser or Evaporator
Fan
Bent, loose or striking venturi Check
Worn motor bearings Section 7.12/Section 7.17
Bent motor shaft Section 7.12/Section 7.17
Condition Possible Cause Remedy / Reference