Service Manual

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2) Defrost-Termination: DTh warms to 77°F (25°C). Ifnot, conrm DTh status.
See"II.D. Thermistor Check." IfDTh is in proper range, DHde-energizes and 3-min.
Comp delay timer starts. If DTh has not warmed to 77°F (25°C), check DT and DH
continuity. Next, check DH amp draw. Once 3-min. Comp delay timer terminates,
Comp icon turns on and Comp and ConFM energize. 4-min. EvapFM delay timer
starts. Once 4-min. EvapFM delay timer terminates, defrost icon turns off, EvapFM
icon turns on and EvapFM energizes. 15-min. temperature display timer starts.
Once 15-min. temperature display timer terminates, "dEF" is replaced by cabinet
temperature on display.
(1) 3-min. Comp delay timer terminates: 3 min. after DH de-energizes, conrm
Comp icon turns on and Comp and ConFM energize. If not, conrm cabinet
temperature is warm enough for Comp operation. Next, check for 115VAC at
CM1 (C) (V) to neutral(W). If115VAC is not present, check CTh status.
See "II.D. Thermistor Check." If CTh ohm reading is in proper range, Comp icon
is on, and 115VAC is not present at CM 1 (C) (V) to neutral (W), replace CM.
If 115VAC is present, check for 115VAC at CUR (V) to neutral (W). If 115VAC is
present at CM1 (C) (V) to neutral (W) and not at CUR (V), check HPS continuity.
See "2.5)h) HPS Activation" above. If HPS is closed and 115VAC present, check
for 115VAC at condensing unit power supply cord (BK) to neutral (W).If 115VAC
is not present at condensing unit power supply cord (BK), replace condensing
unit power supply cord. If 115VAC is present at condensing unit power supply
cord (BK) and ConFM is energized but Comp is not, check for 115VAC at Comp
external protector to neutral (W). If 115VAC is not present, give time for external
protector to cool and reset. If Comp external protector does not reset, replace
Comp external protector. If 115VAC is present on both Comp external protector
wires, check run capacitor (Freezer 2-Section), start capacitor, start relay, and
Comp motor windings. If ConFM is not energized, check ConFM fan blades for
binding and motor winding continuity. If Comp does not start, replace condensing
unit.
(2) 4-min. EvapFM delay timer terminates:
Note: The 4-min. EvapFM delay time is a maximum; if the defrost thermistor
cools to 15°F (-9°C) before the 4-min. EvapFM delay timer terminates, EvapFM
icon turns on and EvapFM energizes. If 15°F (-9°C) is achieved at the defrost
thermistor or the 4min. EvapFM delay timer terminates, conrm EvapFM
icon turns on and EvapFM energizes. Ifnot, conrm doors are closed and DS
engaged, check DS continuity. If DS is engaged and contacts are open, replace
DS. If DS is engaged and contacts are closed, check for 115VAC at CM 5 (F)
(DBU) to neutral (W). If 115VAC is not present, replace CM. If 115VAC is present,
check EvapFM blades for binding and EvapFM continuity.
(3) 15-min. temperature display delay timer terminates: 15 min. after EvapFM
icon turns on and EvapFM energizes, "dEF" is replaced by cabinet temperature
on display. If not, replace CM.
Legend: CL–cabinet light; CM–control module; Comp–compressor; ConFM–condenser
fan motor; CTh–cabinet thermistor; DCD–direct current driver; DH–defrost heater;
DrH–drain heater; DT–defrost thermostat; DTh–defrost thermistor;
EvapFM–evaporator fan motors; HPS–high-pressure switch; MH–mullion heater;
PH–perimeter heater; TXV–thermostatic expansion valve; TXVH–thermostatic
expansion valve heater; CUR–condensing unit receptacle