Hoshizaki KM-901MWH - Manual (Page 29)

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2. Features
a) Maximum Water Supply Period - 6 minutes
"E" control board: The inlet water valve is open during harvest for 6 minutes or the length
of harvest, whichever is shorter.
"G" control board: The inlet water valve is open during harvest for 6 minutes or the
length of harvest minus 0 or 50 seconds (harvest pump timer (S4 dip switch 7)),
whichever is shorter. For details, see "II.C.3.e) Bin Control Selector/Harvest Pump Timer
(S4 dip switch 7)."
b) Harvest Backup Timer and Freeze Timer
The harvest backup timer shuts down the icemaker if, for two cycles in a row, the
harvest cycle takes more than 20 minutes to complete. The control board signals this
problem using 2 beeps every 3 seconds.
The freeze timer shuts down the icemaker if, for two cycles in a row, the freeze cycle
takes longer than the time specified to complete. The control board signals this
problem using 3 beeps every 3 seconds. The freeze timer is factory set using S4 dip
switch 9 &10. For details, see "II.C.3.g) Freeze Timer (S4 dip switch 9 & 10)."
The "ALARM RESET" button on the control board must be pressed with power on to
reset either of these safeties.
c) High Temperature Safety
The temperature of the suction line in the refrigeration circuit is limited by the high
temperature safety. This protects the unit from excessively high temperatures. If the
evaporator temperature reaches 127°F±7°F (53°C±4°C), the control board reads a
.8 kΩ signal from the thermistor and shuts down the icemaker.
The control board will signal this problem using 1 beep every 3 seconds. The "ALARM
RESET" button on the control board must be pressed with power on to reset the safety.
d) Low Water Safety
The control board checks the position of the float switch at the end of the initial 1-minute
fill cycle and at the end of each harvest cycle. If the float switch is in the up position
(electrical circuit closed), the control board changes to the next cycle. If the float switch
is in the down position (electrical circuit open), the control board changes to additional
1-minute fill cycles until water enters the tank and closes the float switch. When the float
switch closes, the control board changes to the next cycle. The unit will not start without
adequate water in the tank. This serves as a low water safety to protect the water pump.
For water-cooled model, if the condenser water supply is shut off, the unit is protected by
the high-pressure switch.
e) High Voltage and Low Voltage Cut-outs
The maximum and minimum allowable supply voltages of this icemaker are limited by
the high voltage and low voltage cut-outs. If miswiring (especially on single phase 3 wire
models) causes excessive voltage (147Vac±5% or more), the high voltage cut-out shuts
down the circuit in 3 seconds and the icemaker automatically stops. The control board
will signal this problem using 7 beeps every 3 seconds.
The icemaker also automatically stops in cases of insufficient voltage (92Vac±5% or
less). The control board will signal this problem using 6 beeps every 3 seconds. When
the proper supply voltage is resumed, the icemaker automatically starts running again.