Service Guide

20
d) Comp and ConFM Diagnosis: Conrm Comp and ConFM energize. Ifnot, 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 at CM C1 (R or V) to neutral (W), check for 115VAC at CR #0
(GY or P) to CR#1(W). If 115VAC is not present, check continuity of HPS. If open,
allow time for HPS to reset (cut out: 300±10 PSIG, cut in: 190±20 PSIG). If HPS does
not reset, see "e) HPS Activation" below. IfHPS is closed and 115VAC is present,
check for 115VAC at CR#4(BK) and CR #6(R) to neutral (W). If 115VAC is present
at CR #4 (BK) and not at CR#6(R), replace CR. If115VAC is present at CR #6 (R)
to neutral (W) and ConFM is energized but Comp is not, give time for Comp external
protector to cool and reset. Next, check Comp start capacitor, start relay, and Comp
motor windings. If Comp does not start, replace Comp. If ConFM is not energized,
check ConFM fan blades for binding and motor winding continuity.
If Comp and ConFM are energized and the cabinet does not cool down, check for a
restriction in the refrigeration circuit, correct TXV operation, and correct refrigerant
charge.
e) HPS Activation (cut out: 300±10 PSIG, cut in: 190±20 PSIG): Conrm ConFM
is energized and fan blade turns freely. Conrmcondenser coil is not clogged or
restricted. Conrm there are no restrictions in the refrigeration circuit (TXV and drier).
Let refrigeration circuit pressures equalize. IfHPS does not reset and pressures
are equalized, replace HPS. Ifpressures are not equalized, reclaim refrigerant and
diagnose refrigeration circuit restriction.
8) Cool Down Achieved–CTh cools to 3°F (1.7°C) below setpoint. EvapFM, Comp, and
ConFM de-energize. Diagnosis: Conrm EvapFM, Comp, and ConFM de-energize.
If not, and EvapFM, Comp, and ConFM were energized longer than 2 min., check
CTh status. See "II.D. Thermistor Check." If CTh ohm reading is in range and EvapFM
continues longer than 2 min., check for 115VAC at CM F5 (W/BU) to neutral (W).
If115VAC is present, replace CM. If Comp and ConFM continue longer than 2 min., and
CTh ohm reading is in range, check for 115VAC at CM C1 (V) to neutral(W). If115VAC
is present, replace CM. If115VAC is not present and Comp and ConFM continue, check
for 115VAC at CR #6(R). If 115VAC is present, replace CR.
9) Defrost–Cabinet temperature is displayed during defrost. There is a 20-min. minimum
defrost time, a 1-hr. maximum defrost time, and a 2-hr. defrost interval.
1a) Time-Initiated: 2-hr. defrost timer terminates. Comp, ConFM, and EvapFM
de-energize.
1b) Manually-Initiated: To initiate a manual defrost, press the manual defrost button
on display. Defrost icon turns on and, if energized, Comp, ConFM, and EvapFM
de-energize. Cabinet temperature is displayed during defrost.
2) Defrost Termination: DTh warms to 44°F (6.6°C). EvapFM, Comp, and ConFM
energize.