Troubleshooting; Unit Will Not Start Or Starts Then Stops; Unit Runs But Has Insufficient Cooling; Unit Operates Long Or Continuously In Cooling - Carrier 69NT40-511-1 Operating And Service Manual

CONDITION

5.1 UNIT WILL NOT START OR STARTS THEN STOPS

No power to unit
Loss of control power Loss of
control power in respective branch
of control circuit only
Loss of control power in respective
branch of control circuit only
Compressor hums, but does not
start
Compressor will occasionally
de-energize for 15 seconds

5.2 UNIT RUNS BUT HAS INSUFFICIENT COOLING

Compressor
Refrigeration System

5.3 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING

Container
Refrigeration System
SECTION 5

TROUBLESHOOTING

POSSIBLE CAUSE
External power source OFF
Start-Stop switch OFF or defective
Circuit breaker tripped or OFF
Modular transformer not connected
Circuit breaker OFF or defective
Control transformer (TR) defective
Fuse (F3) 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 (HTT) open
Low line voltage
Single phasing
Shorted or grounded motor windings
Compressor seized
Contactor (SC) shorting (in high speed mode of two-speed
compressor only)
Compressor speed change (On units with two-speed
compressor)
Compressor valves defective
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
Hot load
Defective box insulation or air leak
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
5-1
REMEDY/
REFERENCE
SECTION
Turn on
Check
Check
6.22
Check
Replace
Check
Check
6.15
6.18
6.7
5.7
Replace
Check
Check
6.7
6.7
Check
Normal
6.7
5.7
5.9
6.15
6.25
2.10/6.24
Check
6.6
Normal
Repair
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
T-268-07