Carrier Streamline Scroll 69NT20-531-300 - Manual (Page 60)

5-1 T-309
SECTION 5
TROUBLESHOOTING
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.1 UNIT WILL NOT START OR STARTS THEN STOPS
External power source OFF Turn on
No power to unit Start-Stop switch OFF or defective Check No power to unit
Circuit breaker tripped or OFF Check
Circuit breaker OFF or defective Check
Loss of control power
Control transformer defective Replace
Loss of control power
Fuse (F3) blown Check
Start-Stop switch OFF or defective Check
Evaporator fan motor internal protector open 6.17
Condenser fan motor internal protector open 6.12
Compressor internal protector open 6.8
Component(s) Not Operating High pressure switch open 5.7 Component(s) Not Operating
Heat termination thermostat open Replace
Loss of communication with expansion module Check Wiring
Malfunction of current sensor Replace
Low line voltage Check
Compressor hums, but does not Single phasing
Check
Compressor hums, but does not
start Shorted or grounded motor windings 6.8
Compressor seized 6.8
5.2 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING
Container
Hot load Normal
Container
Defective box insulation or air leak Repair
Shortage of refrigerant 6.7.1
Evaporator coil covered with ice 5.6
Evaporator coil plugged with debris 6.15
Evaporator fan(s) rotating backwards 6.15/6.17
Defective evaporator fan motor/capacitor 6.18
Air bypass around evaporator coil Check
Controller set too low Reset
Refrigeration System
Compressor service valves or liquid line shutoff valve par-
tially closed
Open valves
completely
Dirty condenser 6.11
Compressor worn 6.8
Current limit (function code Cd32) set to wrong value 3.5.5
Suction modulation valve lost track of step count Power cycle
Suction modulation valve malfunction 6.20
Economizer solenoid valve or TXV malfunction 6.14, 6.19
Unloader valve stuck open 6.19