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SECTION 5
5-1 T-268-07
SECTION 5
TROUBLESHOOTING
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.1 UNIT WILL NOT START OR STARTS THEN STOPS
No power to unit
External power source OFF
Start-Stop switch OFF or defective
Circuit breaker tripped or OFF
Modular transformer not connected
Turn on
Check
Check
6.22
Loss of control power Loss of
control power in respective branch
of control circuit only
Circuit breaker OFF or defective
Control transformer (TR) defective
Fuse (F3) blown
Start-Stop switch OFF or defective
Check
Replace
Check
Check
Loss of control power in respective
branch of control circuit only
Evaporator fan motor internal protector open
Condenser fan motor internal protector open
Compressor internal protector open
High pressure switch open
Heat termination thermostat (HTT) open
6.15
6.18
6.7
5.7
Replace
Compressor hums, but does not
start
Low line voltage
Single phasing
Shorted or grounded motor windings
Compressor seized
Contactor (SC) shorting (in high speed mode of two-speed
compressor only)
Check
Check
6.7
6.7
Check
Compressor will occasionally
de-energize for 15 seconds
Compressor speed change (On units with two-speed
compressor)
Normal
5.2 UNIT RUNS BUT HAS INSUFFICIENT COOLING
Compressor Compressor valves defective 6.7
Refrigeration System
Abnormal pressures
Temperature controller malfunction
Evaporator fan or motor defective
Suction modulation valve malfunction
Suction solenoid valve malfunction
Condenser Pressure Transducer (CPT) defective
Shortage of refrigerant
5.7
5.9
6.15
6.25
2.10/6.24
Check
6.6
5.3 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING
Container
Hot load
Defective box insulation or air leak
Normal
Repair
Refrigeration System
Shortage of refrigerant
Evaporator coil covered with ice
Evaporator coil plugged with debris
Evaporator fan(s) rotating backwards
Defective evaporator fan motor/capacitor
Air bypass around evaporator coil
Controller set too low
Compressor service valves or liquid line shutoff valve
partially closed
Dirty condenser
Compressor worn
Current limit (Code 32) set to wrong value
Suction modulation valve (SMV) malfunction
6.4/6.6
5.6
6.13
6.15/6.16
6.15/6.16
Check
Reset
Open valves
completely
6.17
6.7
3.1.4
6.25