Hoshizaki KM-81BAJ Service Manual page 17

5a) Initial Harvest Cycle – LEDs 5, 6, and 8 are on. WV continues. Comp 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 (S1 dip switch 1 & 2
and S2 dip switch 4). WV is energized during harvest for a maximum of 6 min. or the
length of harvest minus HPT setting (S1 dip switch 7 & 8), 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 K3 #2 (V) to neutral (W). If 115VAC is not
present, check for 115VAC at CB K3 #1 (P) to neutral (W). If 115VAC is present at
CB K3 #1 (P) and not at CB K3 #2 (V), replace CB. If 115VAC is present, check for
115VAC at CR solenoid. If 115VAC is present, confirm contacts are closed. If not,
replace CR. If CR contacts are closed, check Comp external overload, Comp start
capacitor (if applicable), 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 K5 #2 (P) to neutral (W).
If 115VAC is not present and LED 6 is on, replace CB. If 115VAC is present, check for
115VAC at HGV coil and check HGV coil continuity. Replace as needed.
c) WRV Diagnosis: Confirm WRV is not leaking by. If WRV is leaking by, confirm
HGV is open. 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 5, 6, and 7 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 (S1 dip switch 1 & 2 and S2 dip switch 4).
When WV de-energizes, LED 8 turns off and LED 7 turns on. PM energizes. Comp 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 K5 #4 (O). If 115VAC is present, and LED 8 is off, replace CB. If LED 7 is on and PM
is not energized, check for 115VAC at CB K5 #3 (DBU) to neutral (W). 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 (S1 dip switch 1 & 2 and S2 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
S2 dip switch 4. Maximum harvest time allowed is 20 min.
NOTICE! S1 dip switch 7 must remain on. Otherwise, PM will not energize during
the last seconds of harvest.
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