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a)
Freeze Cycle Diagnosis:
Confirm Comp, FM, and PM continue. Confirm that FM
and LLV energize. Confirm WRV opens. Next, confirm HGV and X10 relay de-
energize. During the first 5 min. of freeze, confirm evaporator is cooling. If not,
confirm WV de-energized (not leaking by), HGV de-energized (not bypassing), LLV
and FM energize, TXV and HM operate correctly, WRV opens, Comp is efficient, and
refrigerant charge is correct. See "VIII.A. DIMENSIONS/SPECIFICATIONS."
b)
Comp and FM Diagnosis:
If Comp and FM de-energize once freeze begins, check
that appliance has not shut off on HPS ("POWER OK" LED off). If so, check "3)b)
HPS Diagnosis" above. If CB "POWER OK" LED is on, check for 115VAC at CB K1
#1 (V) or #9 (V) to neutral (W). If 115VAC is not present and LED 1 is on, replace
CB. If 115VAC is present, check for 115VAC at CR or MC coil. If 115VAC is present,
check CR or MC coil and contact continuity. Replace as needed. If CR or MC is
okay, check Comp start relay and start and run capacitors. Next, check Comp motor
winding continuity. If Comp is energized but evaporator is not cooling, check for an
inefficient Comp. See "VIII.A. DIMENSIONS/SPECIFICATIONS."
FM Diagnosis
: If Comp is energized but FM is not, check CB K1 #1 (V) and #9 (V)
wiring circuit for loose connection. If connections are good, check FM capacitor,
motor winding, and blade for binding.
c)
WV and HGV Diagnosis:
If WV is energized, check for 115VAC at CB K1 #6 (O) to
neutral (W). If 115VAC is present after PM energizes in harvest cycle, replace CB.
If 115VAC is not present, replace WV (bypassing). If HGV did not de-energize at
the end of harvest, check for 115VAC at CB K1 #2 (P) to neutral (W). If 115VAC is
present 50 sec. after PM energizes, replace CB. If 115VAC is not present, replace
HGV (bypassing).
d)
PM Diagnosis
: Confirm water is flowing over evaporator from PM and not WV. If PM
de-energizes once freeze begins, check for 115VAC at CB K1 #4 (R) to neutral (W).
If 115VAC is not present, replace CB. If 115VAC is present and PM is de-energized,
check for 115VAC at control switch #5 (W/R) to neutral (W). If 115VAC is present
at CB K1 #4 (R) and not at control switch #5 (W/R), check control switch continuity
between #5 (W/R) and #4 (R). Replace as needed. If 115VAC is present at control
switch #5 (W/R) to neutral (W), check PM capacitor and motor winding continuity.
e)
LLV Diagnosis
: If LLV does not energize, check for 115VAC at CB K1 #3 (BK) to
neutral (W). If 115VAC is not present, replace CB. If 115VAC is present, check coil
voltage and continuity.
f)
Refrigerant Pressures and TXV Diagnosis
: If evaporator is still not cooling, check
refrigerant pressures. See "VIII.A. DIMENSIONS/SPECIFICATIONS."
Next, check TXV for proper operation. Remove TXV bulb and hold it in your hand,
refrigerant low-side pressure should rise, place TXV bulb in ice water, refrigerant
low-side pressure should drop. A 10 to 15 pound pressure swing between warm
and cold conditions indicate a good TXV. If a 10 to 15 pound swing is not present,
replace TXV.
