Hoshizaki KM-320MAH Service Manual page 25

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, FMR energized), continue to step 5a. If FS is open, WV remains energized
through additional 1-min. fill cycles until water enters the water tank and 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.E. 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,
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). The harvest timer has settings of 60, 90, 120, and 180 sec. The
pump-out timer (S4 dip switch 3 & 4) acts in place of the harvest timer during cycles
with a pump-out (S4 dip switch 5 & 6). WV and X11 relay are energized during harvest
for a maximum of 6 min. or the length of harvest minus 50 sec., whichever is shorter.
50 sec. before harvest terminates, PM energizes. 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. If Comp is energized and evaporator is not warming, check that HGV
energizes and opens. Check for 115VAC at CB K1 #2 (P) to a neutral (W). If 115VAC
is not present and LED 2 is on, replace CB. If 115VAC is present, check coil voltage
and continuity. Replace as needed. Confirm that LLV is de-energized and closed (not
bypassing). If energized, replace CB. If de-energized and bypassing, replace LLV.
Confirm WRV is not leaking by. If evaporator is warming, PM energizes for the last 50
sec. of harvest.
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.
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