Carrier 69NT40-561-201 - Heating, Defrost, and Pressure Issues

5−2T-364
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.3 UNIT RUNS BUT HAS INSUFFICIENT COOLING
Refrigeration system
Abnormal pressures 5.7
Abnormal temperatures 5.13
Abnormal currents 5.14
Controller malfunction 5.9
Evaporator fan or motor defective 6.14
Compressor service valves or liquid line shutoff valve
partially closed
Open valves
completely
Frost on coil 5.10
Digital unloader valve stuck open Replace
Electronic expansion valve Replace
5.4 UNIT WILL NOT HEAT OR HAS INSUFFICIENT HEATING
No operation of any kind
Start−Stop switch OFF or defective Check
Circuit breaker OFF or defective Check
External power source OFF Turn ON
No control power
Circuit breaker or fuse defective Replace
Control Transformer defective Replace
Evaporator fan internal motor protector open 6.14
Heat relay defective Check
Heater termination thermostat open 6.13
Unit will not heat or has insuffi-
cient heat
Heater(s) defective 6.13
Heater contactor or coil defective Replace
Evaporator fan motor(s) defective or rotating backwards 6.13/6.14
Evaporator fan motor contactor defective Replace
Controller malfunction 5.9
Defective wiring Replace
Loose terminal connections Tighten
Low line voltage 2.3
5.5 UNIT WILL NOT TERMINATE HEATING
Unit fails to stop heating
Controller improperly set Reset
Controller malfunction 5.9
Heater termination thermostat remains closed along with
the heat relay
6.13
5.6 UNIT WILL NOT DEFROST PROPERLY
Will not initiate defrost
automatically
Defrost timer malfunction (Cd27) Table 3−5
Loose terminal connections Tighten
Defective wiring Replace
Defrost temperature sensor defective or heat termination
thermostat open
Replace
Heater contactor or coil defective Replace
Will not initiate defrost
manually
Manual defrost switch defective Replace
Keypad is defective Replace
Defrost temperature sensor open Replace
Initiates but relay (DR) drops out Low line voltage 2.3