Carrier 69NT40-511-199 - Manual (Page 92)

5-2 T-268-07
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.4 UNIT WILL NOT HEAT OR HAS INSUFFICIENT HEATING
No power to unit
Start-Stop switch OFF or defective
Circuit breaker OFF or defective
External power source OFF
Check
Check
Turn on
No control power
Circuit breaker or fuse defective
Transformer defective (TR)
Evaporator fan internal motor protector open
Heat relay defective
Heater termination switch open
Replace
Replace
6.15
Check
6.13
Unit will not heat or has insufficient
heat
Heater(s) defective
Heater contactor or coil defective
Evaporator fan motor(s) defective or rotating backwards
Evaporator fan motor contactor defective
Temperature controller malfunction
Defective wiring
Loose terminal connections
Low line voltage
6.14
Replace
6.15/6.16
Replace
5.9
Replace
Tighten
2.4
5.5 UNIT WILL NOT TERMINATE HEATING
Unit fails to stop heating
Temperature controller improperly set
Temperature controller malfunction
Heater termination switch remains closed along with the
heat relay
Reset
5.9
6.13
5.6 UNIT WILL NOT DEFROST PROPERLY
Will not initiate defrost automatically
Defrost timer malfunction
Loose terminal connections
Defective wiring
Defrost termination sensor defective or heat termination
switch open
Heater contactor or coil defective
3.1.4
Tighten
Replace
Replace
Replace
Will not initiate defrost manually
Manual defrost switch defective
Defrost termination sensor open
Replace
4.4.6
Initiates but relay (DR) drops out Low line voltage 2.4
Initiates but does not defrost
Heater contactor or coil defective
Heater(s) burned out
Replace
6.14
Frequent defrost Wet load Normal