Unit Operates Long Or Continuously In Cooling; Troubleshooting - Carrier 69NT40-561-399 Operation And Service Manual

6.1 UNIT WILL NOT START OR STARTS THEN STOPS
Condition
No power to unit
Loss of control power
Component(s) not operating
6.2

UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING

Condition
Container
Refrigeration system
SECTION 6

TROUBLESHOOTING

Possible Cause
External power source OFF
Start−Stop switch OFF or defective
Circuit breaker tripped or OFF
Autotransformer not connected
Circuit breaker OFF or defective
Control transformer defective
Fuse (F3A/F3B) blown
Start−Stop switch OFF or defective
Evaporator fan motor internal protector open
Condenser fan motor internal protector open
Compressor internal protector open
High pressure switch open
Heat termination thermostat open
Malfunction of current sensor
Possible Cause
Hot load
Defective box insulation or air leak
Shortage of refrigerant
Evaporator coil covered with ice
Evaporator coil plugged with debris
Air bypass around evaporator coil
Controller set too low
Compressor service valves or liquid line shutoff valve par-
tially closed
Dirty condenser
Compressor worn
Current limit (function code Cd32) set to wrong value
Economizer solenoid valve malfunction
Digital unloader valve stuck open
Electronic expansion valve
6–1
Remedy/Refer-
ence Section
Turn On
Check
Check
Section 5.2.2
Check
Replace
Check
Check
Section 7.14
Section 7.8
Section 7.8
Section 6.7
Replace
Replace
Remedy/Refer-
ence Section
Normal
Repair
Section 7.3
Section 6.6
Section 7.13
Check
Reset
Open valves
completely
Section 7.10.1
Section 7.8
Section 4.4.3
Section 7.17
Section 7.21.1
Section 7.16.1
T-365