Service Manual

15
c) CM Diagnosis: Conrm green LED is ashing. If not, check for 115VAC between
CM 2 (L) black (BK) wire and CM 3 (N) neutral white (W) wire. If 115VAC is
not present, check power cord connections and breaker/fuse. Conrm wiring
connections are secure for both CM 2 (L) black (BK) (power supply) and CM 3 (N)
white (W) (neutral).
If 115VAC is present and green LED is not ashing, replace CM.
d) Comp/CondFM Diagnosis: Check that Comp and ConFM energize. If not, conrm
that the temperature is above setpoint. Next, check for 115VAC at CM 1 (C)
brown(BR) wire to neutral white (W) wire. If 115VAC is not present, replace CM.
If 115VAC is present, check HPS continuity (if applicable). See "f) HPS Activation"
below.
Comp: If 115VAC is present, check Comp external overload, start cap, start relay,
and Comp motor windings. Replace as needed.
CondFM: If 115VAC is present, check fan blade for binding, then check ConFM
motor windings.
e) EvapFM Diagnosis: Check that EvapFM(s) energize. If not, check for 115VAC at
CM 5 (F) dark blue (DBU) wire to neutral white (W) wire. If 115VAC is not present,
replace CM. If 115VAC is present, check fan blades for binding, then check EvapFM
motor windings.
f) HPS Activation: Check continuity of HPS. If open, allow time for system pressure
to equalize and HPS to reset. If HPS does not reset, replace HPS and diagnose
reason for HPS activation. Conrm ConFM is energized and fan blade turns freely.
Check that the condenser coil is not clogged or restricted. Check that there are no
restrictions in the refrigeration circuit (drier).
g) PH and MH Diagnosis (Freezer only): PH and MH follow Comp operation. When
Comp is energized, PH and MH are energized. If 115VAC is present, check amp
draw of PH and MH. If an amp reading is not present, check the continuity of PH
and MH. If defective, replace PH or MH.
If Comp, ConFM, and EvapFM are energized and the cabinet does not cool down,
check for a restriction in the refrigeration circuit, low refrigerant charge, or inefficient
Comp.
5) Cool Down Achieved–Temperature cools to setpoint. Comp and ConFM de-energize.
UC/WT Refrigerators and Freezers: EvapFM de-energizes.
Prep Table: EvapFM continues.
Diagnosis: If temperature setpoint achieved and Comp, ConFM, and EvapFM(except
PT models) does not de-energize, check CTh and TD continuity. If CTh or TD is
defective, replace. If CTh and TD are good and either the Comp, ConFM, and/or
EvapFM (except PT models) continue, or if EvapFM on PT models de-energizes,
replace CM.