Service Guide

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IfComp external protector does not reset, replace Comp external protector. If115VAC
is present, check run capacitor, 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 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. See nameplate for correct charge amount.
e) EvapFM Diagnosis: Conrm EvapFM energizes. If not, conrm doors are closed and
DS engaged. Next, check for 115VAC at DSR #8 (GY) to DSR#7neutral (W).
If 115VAC is not present, check DS continuity. If DS is engaged and contacts are
open, replace DS. If 115VAC is present, check for 115VAC at CM F5(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 at DSR #6 (W/BU) to
neutral (W) and not at DSR #4 (DBU) to neutral (W), replace DSR. If 115VAC is
present at DSR#4(DBU) to neutral (W), check EvapFM blades for binding and
EvapFM continuity.
f) MH and PH Diagnosis: Conrm MH and PH energize. If not, check for 115VAC
at CM C1 (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 (V) to neutral (W), check for 115VAC at CR #0 (P) to
CR #1 (W). If 115VAC is not present, check continuity of HPS. Ifopen, allow time for
HPS to reset (cut out: 490 ±10 PSIG, cut in: 370 ±20 PSIG). If HPS does not reset,
see "g) HPS Activation" below. If HPS is closed and 115VAC is present, check amp
draw of MH and PH. If an amp reading is not present, check continuity of MH or PH.
If open, replace MH or PH.
g) HPS Activation (cut out: 490 ±10 PSIG, cut in: 370 ±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–DrH continues. CTh cools to 3°F (1.7°C) below setpoint. Comp,
ConFM, EvapFM, MH, and PH de-energize.
a) Diagnosis: Conrm Comp, ConFM, EvapFM, MH, and PH 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 proper range:
b) CM Diagnosis: Check for 115VAC at CM C1 (V) to neutral (W) and CM F5 (W/BU) to
neutral (W). If115VAC is present on either CM C1 or CM F5, replace CM.
c) Comp and ConFM Diagnosis: Check for 115VAC at CR#6(R) to neutral (W).
If115VAC is present, replace CR.