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3-1
SECTION 3
TROUBLESHOOTING
INDICATION/
REFERENCE
TROUBLE
POSSIBLE CAUSES
SECTION
3.1 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
Loss of control power
Circuit breaker OFF or defective
Check
Control transformer defective (TR)
Replace
Fuse blown (3A or 6A)
Check
Start-Stop switch OFF or defective
Check
Evaporator fan motor internal protector open
4.14
Condenser fan motor internal protector open
4.17
Compressor internal protector open
4.5
High pressure switch open
3.7
Compressor hums,
Low line voltage
Check
but does not start
Single phasing
Check
Shorted or grounded motor windings
4.5
Compressor seized
4.5
3.2 UNIT RUNS BUT HAS INSUFFICIENT COOLING
Compressor
Compressor valves defective
4.5
Refrigeration System
Abnormal pressures
3.7
Temperature controller malfunction
3.9
Evaporator fan or motor defective
4.14
Modulating solenoid valve malfunction
4.25
Suction solenoid valve malfunction
1.11/4.24
3.3 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING
Container
Hot load
Normal
Defective box insulation or air leak
Repair
Refrigeration System
Shortage of refrigerant
4.2/4.4
Evaporator coil covered with ice
3.6
Evaporator coil plugged with debris
4.13
Evaporator fan(s) rotating backwards
4.14/4.27
Defective evaporator fan motor/capacitor
4.14/4.27
Air bypass around evaporator coil
Check
Controller set too low
Reset
Compressor service valves or liquid
Open valves
line shutoff valve partially closed
completely
Dirty condenser
4.16 or 4.21
Compressor worn
4.5
Current limit (Code 31) set to wrong value
1.13.4
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