Carrier 69NT40-561-201, Operation & Service Manual, Page: 80 / 117

5 − 5 T-364
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.12 COMPRESSOR OPERATING IN REVERSE
NOTE
The compressor may start in reverse for up to 10 seconds to determine correct phase rotation if
required for phase detection.
CAUTION
Allowing the scroll compressor to operate in reverse for more than two minutes will result in internal
compressor damage. Turn the start − stop switch OFF immediately.
Electrical
Incorrect wiring of compressor
Check
Incorrect wiring of compressor contactor(s)
Incorrect wiring of current sensor
5.13 ABNORMAL TEMPERATURES
High discharge temperature
Condenser coil dirty 6.10
Condenser fan rotating backwards 6.11
Condenser fan inoperative 6.11
Refrigerant overcharge or noncondensibles 6.3
Discharge service valve partially closed Open
Electronic expansion valve (EEV) control malfunction Replace
Failed suction pressure transducer (SPT) or evaporator
pressure transducer (EPT)
Replace
Discharge temperature sensor drifting high Replace
Failed economizer expansion valve, economizer coil, or
economizer solenoid valve
Replace
Plugged economizer expansion valve, economizer coil, or
economizer solenoid valve
Replace
Loose or insufficiently clamped sensor Replace
5.14 ABNORMAL CURRENTS
Unit reads abnormal currents Current sensor wiring Check