Hoshizaki KM-420MWJ Service Manual page 18

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.
5c) Initial Harvest Cycle Termination Diagnosis: 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). Check discharge line
temperature. For a thermistor check, see "II.F. Thermistor Check." If 1-min. fill cycle
starts after harvest timer terminates, check that FS is clean and operating properly, see
"II.E. Float Switch Check and Cleaning." If FS is closed, CB proceeds to the next cycle.
If not, replace CB.
Note: The minimum total time allowed by CB for a complete harvest cycle is based on
S5 dip switch 4. Maximum harvest time allowed is 20 min.
NOTICE! S4 dip switch 7 must remain on. Otherwise, PM will not energize during
the last seconds of harvest.
6) Freeze Cycle – LED 1, 2, and 3 are on. Comp, FMR, and PM continue. FM and
LLV energize. HGV de-energizes. Appliance is held in freeze by a 5-min. short cycle
protection timer. After 5-min. short cycle protection timer terminates and FS opens,
freeze cycle terminates.
Note: PM power supply continues from CB K1 #4 (R) in harvest and in freeze.
Anti-Slush: When anti-slush is enabled (S5 dip switch 5 "ON"), PM de-energizes when
thermistor reaches 36°F (2.2°C) (5.8 kΩ) for 10 sec. then, energizes for the remainder
of the freeze cycle.
a) Freeze Cycle Diagnosis: Confirm Comp, FMR, and PM continue. Confirm that FM
and LLV energize. Confirm WRV opens. Next, confirm HGV de-energizes.
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. Specification and Performance Data
Sheets."
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