Carrier 69NT40-541-001, Operation And Service

Page: 85 / 156

6–1 T-316
SECTION 6
TROUBLESHOOTING
CONDITION POSSIBLE CAUSE
REMEDY /
REFERENCE
6.1 UNIT WILL NOT START OR STARTS THEN STOPS
No power to unit
External power source OFF Turn on
Start-Stop switch OFF or defective Check
Circuit breaker tripped or OFF Check
Autotransformer not connected 5.2.2
Loss of control power
Circuit breaker OFF or defective Check
Control transformer defective Replace
Fuses (F3A, F3B) blown Check
Start-Stop switch OFF or defective Check
Component(s) Not Op-
erating
Evaporator fan motor internal protector open 7.16
Condenser fan motor internal protector open 7.11
Compressor internal protector open 7.8
High pressure switch open 6.7
Heat termination thermostat open Replace
Compressor hums, but
does not start
Low line voltage Check
Single phasing Check
Shorted or grounded motor windings 7.8
Compressor seized 7.8
6.2 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING
Container
Hot load (Failure to Pre-cool) Normal
Defective box insulation or air leak Repair
Refrigeration System
Shortage of refrigerant 7.7.1
Evaporator coil covered with ice 6.6
Evaporator coil plugged with debris 7.15
Evaporator fan(s) rotating backwards 7.15 / 7.16
Defective evaporator fan motor/capacitor 7.17
Air bypass around evaporator coil Check
Controller set too low Reset
Compressor service valves or liquid line shutoff valve partially closed
Open valves
completely
Dirty condenser 7.10
Compressor worn 7.8
Current limit (function code Cd32) set to wrong value 4.3.5
Suction modulation valve malfunction 7.18