Hoshizaki KM-901MAH Service Manual page 52

5) Freeze Cycle – LED 1 is on. Comp and FMR remain energized, PM, LLV, and
FM energize. WV and HGV de-energize. The unit is held in freeze by a 5-minute
short cycle protection timer (CB will not accept a signal from F/S). After the
5-minute short cycle protection timer expires, CB turns freeze termination over to
F/S. Diagnosis: During the first 5 minutes of freeze, confirm that the evaporator
temperature drops. After 5 minutes in freeze, disconnect black F/S connector from
CB BLACK K5 connector. If the evaporator is not cold, check to see if HGV is still
open or if TXV is not opening properly, if WV is continuing to fill the reservoir, if there
are improper unit pressures, an inoperative Comp, or an inoperative HM. The unit
should switch out of the freeze cycle ("G" CB - 15 second delay after F/S opens before
terminating the freeze cycle). If the unit switches out of freeze with F/S removed, but
would previously not switch out of freeze with F/S connected (long freeze - 3 beep
alarm), F/S may be sticking. To check and clean F/S, see "IV.D. Float Switch Check
and Cleaning." If the unit remains in freeze (longer than 15 seconds on "G" CB)
after disconnecting the black F/S connector, replace CB. See "V.P. Removal and
Replacement of Control Board."
Note: Normal freeze cycle will last 20 to 40 minutes depending on model and
conditions. Cycle times and pressures should follow performance data provided
in this manual. See "III.C. Performance Data."
6) Pump-Out Cycle – (10/20 second pump-out) – LEDs 1, 3, and 2 are on. LED 4 is
on when S4 dip switch 3 & 4 are set to 3 off and 4 on. Comp and FMR remain
energized, HGV energizes. WV energizes if S4 dip switch 3 off and 4 on. LLV and
FM de-energize. PM stops for 2 seconds, then reverses for 10/20 seconds depending
on pump-out timer S4 dip switch 3 & 4 setting. When the pump-out timer expires, the
pump-out is complete. The pump-out frequency control is factory set for every 10th
cycle, and generally no adjustment is required. However, where water quality is bad
and the icemaker needs a pump-out more often, the pump-out frequency can be
adjusted. The pump-out frequency control (S4 dip switch 5 & 6) can be set to have
a pump-out occur every cycle, or every 2, 5, or 10 cycles. For details, see "II.C.3.d)
Pump-Out Frequency Control (S4 dip switch 5 & 6)."
Timing of the first pump-out is dependent on CB. "E" CB first pump-out is after the first
freeze cycle. "G" CB first pump-out is determined by S4 dip switch 5 & 6. See the table
below.
"E" & "G" Control Board Settings
S4 Dip Switch Setting
No. 5 No. 6
OFF OFF
ON OFF
OFF ON
ON ON
Diagnosis: If PM does not reverse, check to see if S4 and S5 dip switch settings are in
the factory default position. Check PM circuit and capacitor, check #5 pin (DBu wire) on
CB K1 ten-pin connector for voltage. If water does not pump out, check and clean the
check valve assembly and tubing.
Pump-Out
"E" Control Board
Frequency
Every cycle After 1st freeze cycle
Every 2 cycles
Every 5 cycles
Every 10 cycles
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1st Pump-Out
"G" Control Board
After 2nd freeze cycle
After 3rd freeze cycle
After 6th freeze cycle
After 11th freeze cycle