T-340
6–2
6.3 Unit Runs But Has Insufficient Cooling
Refrigeration system
Abnormal pressures
Abnormal temperatures
Abnormal currents
Controller malfunction
Evaporator fan or motor defective
Compressor service valves or liquid line shutoff valve
partially closed
Open valves completely
Frost on coil
Digital unloader valve stuck open
Replace
Electronic expansion valve
Replace
6.4 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
Heat relay defective
Check
Heater termination thermostat open
Unit will not heat or has
insufficient heat
Heater(s) defective
Heater contactor or coil defective
Replace
Evaporator fan motor(s) defective or rotating back
-
wards
Evaporator fan motor contactor defective
Replace
Controller malfunction
Defective wiring
Replace
Loose terminal connections
Tighten
Low line voltage
6.5 Unit Will Not Terminate Heating
Unit fails to stop heating
Controller improperly set
Reset
Controller malfunction
Heater termination thermostat remains closed along
with the heat relay
6.6 Unit Will Not Defrost Properly
Will not initiate defrost
automatically
Defrost timer malfunction (Cd27)
Loose terminal connections
Tighten
Defective wiring
Replace
Defrost temperature sensor defective or heat termi
-
nation thermostat open
Replace
Heater contactor or coil defective
Replace
Condition
Possible Cause
Remedy / Reference