28
9)
Defrost–LED 5 (ConFM) is on:
Temperature-Initiated Defrost:
Dth cools to 13°F (-10°C), CB initiates defrost. EvapFM
and ConFM continue. Comp de-energizes. If ConFM is off, ConFM energizes once
defrost starts.
Time-Initiated Defrost:
If the factory time-initiated setting is moved from 0 defrost per
24 hours, the unit enters the defrost cycle once the time of the new setting expires.
EvapFM and ConFM continue. Comp de-energizes. If ConFM is off, ConFM energizes
once defrost starts.
Defrost Termination:
Dth warms to 40
°
F (4.4
°
C). EvapFM and ConFM continue.
2.5 minutes later Comp and PH (if PH switch is on (red marking visible)) energize.
Diagnosis:
Has Dth cooled to 13°F (-10°C)? Confirm Dth status, see "IV.C. Thermistor
Check." Confirm that Comp stops. If not, check for 115VAC at K1 connector pin #10
gray (GY) wire to any white (W) neutral wire. If 115VAC is present, CB is bad and must
be replaced. If Comp is on and 115VAC is not present, check Comp relay for closed
contacts. Confirm EvapFM and ConFM continue to run. If not, check for 115VAC at
K1 connector pin #3 dark blue (DBU) wire to any white (W) neutral wire for EvapFM
and 115VAC at red K9 connector pin #2 brown (BR) to any white (W) neutral wire
for ConFM. If 115VAC is not present, CB is bad and must be replaced. If 115VAC is
present, check that EvapFM or ConFM is not binding. Then, check EvapFM and ConFM
windings for continuity.
Confirm defrost termination. Confirm evaporator has warmed to defrost termination
temperature of 40°F (4.4°C). Check Dth status, see "IV.C. Thermistor Check."
2.5 minutes later LED 4 comes on and Comp energizes. EvapFM and ConFM continue.
Legend:
CB
–control board;
ConFM
–condenser fan motor;
Comp
–compressor;
CTh
–cabinet thermistor;
DB
–display board;
DTh
–defrost thermistor;
EvapFM
–evaporator fan motor;
PH
–perimeter heater
