5-2
T-294-01
CONDITION
POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.4 UNIT WILL NOT HEAT OR HAS INSUFFICIENT HEATING
Start-Stop switch (ST) OFF or defective
Check
No power to unit
Circuit breaker (CB) OFF or defective
Check
No power to unit
External power source OFF
Turn on
Circuit breaker (CB) or fuse (F) defective
Replace
Transformer defective (TR)
Replace
No control power
Evaporator fan internal motor protector (IP) open
6.16
No control power
Heat relay (TH) defective
Check
Heater termination thermostat (HTT) open
6.14
Heater(s) (DHBL, DHBR, DHTL, DHTR) defective
6.15
Heater contactor (HR) or coil defective
Replace
Evaporator fan motor(s) defective or rotating backwards
6.16/6.17
Unit will not heat or has
Evaporator fan motor contactor (EF or ES) defective
Replace
Unit will not heat or has
insufficient heat
Temperature controller malfunction
5.9
Defective wiring
Replace
Loose terminal connections
Tighten
Low line voltage
2.4
5.5 UNIT WILL NOT TERMINATE HEATING
Temperature controller improperly set
Reset
Unit fails to stop heating
Temperature controller malfunction
5.9
Unit fails to stop heating
Heater termination thermostat (HTT) remains closed along
with the heat relay (TH)
6.14
5.6 UNIT WILL NOT DEFROST PROPERLY
Defrost timer malfunction
3.1.4
Loose terminal connections
Tighten
Will not initiate defrost
Defective wiring
Replace
Will not initiate defrost
automatically
Defrost termination sensor (DTS) defective or heat
termination thermostat (HTT)open
Replace
Heater contactor (HR) or coil defective
Replace
Will not initiate defrost manually
Manual defrost switch (MDS) defective
Replace
Will not initiate defrost manually
Defrost termination sensor (DTS) open
4.4.6
Initiates but relay (DR) drops out
Low line voltage
2.4
Initiates but does not defrost
Heater contactor (HR) or coil defective
Replace
Initiates but does not defrost
Heater(s) (DHBL, DHBR, DHTL, DHTR) burned out
6.15
Frequent defrost
Wet load
Normal
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