Hoshizaki KM-901MAJ Service Manual page 18

4) 1-Min. Fill Cycle – LED 4 is on. WV and X11 relay energize. After 1 min., CB checks for
a closed FS. If FS is closed, the harvest cycle begins. If harvest cycle begins (Comp,
HGV, FM*, FMR energized), continue to step 5a. If FS is open, WV remains energized
until FS closes (low water safety protection during initial start up and at the end of each
harvest). Diagnosis: Check that water enters the water tank. If not, check that the water
supply line shut-off valve is open and screens or external filters are clear. Check for
115VAC at CB K1 #6 (O) to neutral (W). If 115VAC is not present, replace CB. If 115VAC
is present, and WV does not energize, check for 115VAC at WV. If 115VAC is present,
check coil continuity. If open, replace WV. If the water tank fills, but the appliance fails to
start harvest (Comp energized), check for open FS. See "II.F. Float Switch Check and
Cleaning." If FS is closed and CB fails to start the harvest cycle after 1 min., replace
CB.
5a) Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV and X11 relay continue. Comp,
FM* (if connected to CB K1 connector pin #9), FMR, HGV, and X10 relay 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 and X11 relay 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 #1 or #9 (V) to neutral (W). If 115VAC is
not present, check for 115VAC at CB K1 #7 or #10 (BR) to neutral (W). If 115VAC is
present at #7 or #10 (BR) and not at #1 or #9 (V), replace CB. If 115VAC is present,
check for 115VAC at CR or MC solenoid. If 115VAC is present, confirm contacts are
closed. If not, replace CR or MC. If CR or MC 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, replace CB. If 115VAC is present, check for 115VAC at HGV
coil and check HGV coil continuity. Replace as needed.
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).
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