Service Manual

18
2b) Manually Initiated Defrost-Termination: Has DTh warmed to 59°F (15°C)? If not
yet conrmed, conrm DTh status. See "II.D. Thermistor Check." If DTh is in proper
range, DHde-energizes and 2 delay timers start. If DTh has not warmed to 59°F
(15°C), check DT and DH continuity. Next, check DH amp draw.
(1) 3-min. Comp/ConFM and EvapFM delay timers terminate: 3 min. after DH
de-energizes, conrm defrost icon turns off, Comp and EvapFM icons turn on,
and Comp, ConFM, and EvapFM energize. If not, conrm cabinet temperature is
warm enough for Comp and ConFM operation.
Comp and ConFM: Check for 115VAC at CM C1 (R or 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, replace CM. If 115VAC is present, check for
115VAC at CR #4(BK) to neutral (W) and CR#6(R) to neutral (W). If 115VAC is
present at CR #4 (BK) to neutral (W) but not at CR #6(R) to neutral (W), replace
CR. If 115VAC is present at CR #6 (R) and Comp or ConFM are not energized,
check Comp start components, Comp protector (internal on 1-section, external
on 2-section), and Comp motor winding continuity. If ConFM is not energized,
check ConFM fan blades for binding and motor winding continuity.
EvapFM: Conrm EvapFM icon turns on and EvapFM energizes. If not, conrm
doors are closed and DS engaged. Next, check for 115VAC at CMF5 (Y or
W/BU) to neutral (W). If 115VAC is not present, replace CM. If 115VAC is present,
checkfor 115VAC at DSR#4(DBU) to neutral(W). If115VAC is not present,
check for 115VAC at DSR#6(Y or W/BU) to neutral (W). If115VAC is present
on DSR #6 (Y or W/BU) to neutral (W) and not on DSR #4(DBU) to neutral (W),
replace DSR. If 115VAC is present on DSR #4 (DBU) to neutral (W) and EvapFM
is not energized, check EvapFM blades for binding and EvapFM continuity.
(2) 15-min. temperature display delay timer terminates: 12 min. after Comp,
ConFM, and EvapFM energize, "dEF" is replaced by cabinet temperature on
display. If not, replace CM.
Legend: CM–control module; Comp–compressor; ConFM–condenser fan motor;
CR–compressor relay; CTh–cabinet thermistor; DH–defrost heater;
DrH–drain heater; DSR–door switch relay; DT–defrost thermostat; DTh–defrost
thermistor; EvapFM–evaporator fan motors; HPS–high-pressure switch;
MH–mullion heater; PH–perimeter heater; TXV–thermostatic expansion valve