Hoshizaki KM-350MWJ Service Manual page 17

5a) Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV continues. Comp, FMR, and
HGV energize. CB monitors the warming of the evaporator via the thermistor located
on the suction line. When the thermistor reaches 48°F (9°C), CB reads 3.9 kΩ from the
thermistor and turns harvest termination over to the harvest timer (S4 dip switch 1 & 2
and S5 dip switch 4). WV are energized during harvest for a maximum of 6 min. or the
length of harvest minus HPT setting (S4 dip switch 6), whichever is shorter. See step 5b
below.
a) Comp Diagnosis: Check that evaporator is warming. If not, confirm that Comp
energizes. If not, check for 115VAC at CB K1 #9 (Y) to neutral (W). If 115VAC is not
present, check for 115VAC at CB K1 #10 (BK) to neutral (W). If 115VAC is present
at #10 (BK) and not at #9 (Y), replace CB. If 115VAC is present, check for 115VAC
at mode switch #2 (Y) to neutral and mode switch #1 (V) to neutral. If 115VAC is
present at #2 (Y) and not at #1 (V), confirm mode switch is in "ICE" position. If in
"ICE" position, check mode switch continuity. If open, replace mode switch. If 115VAC
is present at mode switch #1 (V), check for 115VAC at CR solenoid. If 115V AC is
present, confirm contacts are closed. If not, replace CR. If CR contacts are closed,
check Comp external overload, Comp start and run capacitors, Comp start relay, and
Comp motor winding.
b) HGV Diagnosis: If Comp is energized and evaporator is not warming, check that
HGV energizes and opens. Check for 115VAC at CB K1 #2 (P) to neutral (W).
If 115VAC is not present, check for 115VAC at CB K1 #1 (V). If 115VAC is not present,
check wiring for loose connection from CB 10 pin connector pin #1 (V) to mode
switch. If 115VAC is present on #1 (V) and not at #2 (Y), replace CB.
If 115VAC is present at #2 (Y), check for 115VAC at HGV coil and check HGV coil
continuity. Replace as needed. Note: LED is off when HGV is energized and on when
LLV/FM are energized.
c) LLV Diagnosis: Confirm that LLV is de-energized and closed (not bypassing).
If energized, replace CB. If de-energized and bypassing, replace LLV.
d) WRV Diagnosis: Confirm WRV is not leaking by. If WRV is leaking by, confirm HGV
is open and LLV is closed. Next, check for proper refrigerant pressures. If refrigerant
pressures are correct, adjust or replace WRV. See "IV.C. Water Regulating Valve
Adjustment (water-cooled models).".
5b) Harvest Pump Time (Harvest Assist) – LEDs 1 and 3 are on. When the thermistor
reaches 48°F (9°C), CB reads 3.9 kΩ from the thermistor and turns harvest termination
over to the harvest timer (S4 dip switch 1 & 2 and S5 dip switch 4).
When WV de-energizes, LED 4 turns off and LED 3 turns on. PM energizes. Comp,
FMR, and HGV continue.
Diagnosis: Place a thermometer on the suction line next to the thermistor. Has it
warmed to 48°F (9°C) or warmer? Confirm thermistor status. See "II.F. Thermistor
Check." If the thermistor reading is in proper range, dip switch 7 is on, and PM does not
energize before harvest terminates, replace CB. If WV continues, check for 115VAC at
CB K1 #6 (O). If 115VAC is present, and LED 4 is off, replace CB. If LED 3 is on and PM
is not energized, check for 115VAC at CB K1 #4 (R). If 115VAC is not present, replace
CB. If 115VAC is present and PM is not energized, check PM capacitor and motor
winding continuity.
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