Operation; Normal Harvest Cycle; Final Checklist - Hoshizaki KM-520MAJ-E Installation Manual

9. Operation

The steps in the start-up/operation sequence are as
follows:
1) 1 Minute Fill Cycle
The unit always starts in the 1 minute fill cycle.
When power is applied to the unit, the water valve is
energized and the fill period begins. After 1 minute
the board checks for a closed float switch. If the float
switch is closed the harvest cycle begins. If not,
the unit will not start without adequate water in the
sump. This serves as a low water safety shut off. The
water valve will remain energized through additional
1 minute cycles until sufficient water enters the sump
and the float switch closes.
2) 1st Harvest Cycle
The compressor and hot gas valve energize, water
valve remains open and harvest begins. The control
board monitors the warming of the evaporator via
the thermistor located on the suction line. When
the thermistor reaches 9°C, the control board
reads 3.9kΩ from the thermistor and turns harvest
thermination over to the harvest timer (S4 dip swith
1 & 2 and S5 dip switch 4). The control board is
factory set for normal conditions. This adjustment
can vary the defrost timer from 1 to 3 minutes.
3) Harvest Pump Time (Harvest Assist)
50 seconds before harvest termination, the water
valve de-energizes and the water pump energizes
for the last 50 seconds of harvest.
4) Freeze Cycle
After the harvest timer terminates the harvest cycle,
the hot gas and water pump de-energize, and the
ice production cycle starts. For the first 5 minutes
the control board will not accept a signal from the
float switch. This 5 minute minimum freeze acts as
a short cycle protection. At the end of 5 minutes
the float switch assumes control. As ice builds on
the evaporator the water level in the sump lowers.
Once the thermistor reaches 2.2°C (5.8kΩ) the water
pump de-energizes for 10 sec. (anti slush), then
energizes for the remainder of the freeze cycle. The
freeze cycle continues until the float switch opens
and terminates ice production.
5) Pump-Out
When the float switch opens, the control board
terminates the freeze cycle and starts pump-out.
The compressor continues, the hot gas valve and
drain valve energize and the pump-out timer starts.
The water pump stops for 2 seconds, then restarts
for 10/20 seconds. When the pump-out timer stops
counting, the pump-out is complete. The control
board allows for adjustment for pump-out to occur
every cycle or every 10th cycle (S4 dip switch 5).

6) Normal Harvest Cycle

Same as the 1st harvest cycle.
Return to step 2) above.
Note: Unit continues to cycle until bin control is
satisfied or power is switched off. The unit always
restarts at the 1-min. fill cycle.
Note: If the icemaker does not start or complete
a cycle of operation, contact your nearest
Hoshizaki Distributor for guidance.

10. Final Checklist

1) Is the icemaker level?
2) Is the icemaker in a site where the ambient
temperature is within +7°C to +40°C all year
around?
3) Is there at least a 15 cm. clearance around the
icemaker for maintenance or service?
4) Have all shipping tape(s), packing and cartons
been removed from the icemaker? Is the cube
guide in its correct position?
5) Have all electrical and piping connections been
made?
6) Has the power supply voltage been checked or
tested against the nameplate rating?
7) Are the water supply line shut-off valve and drain
valve installed? Has the water supply pressure
been checked to ensure a minimum of .7 bar and a
maximum of 8 bar?
8) Have the compressor hold-down bolts and
refrigerant lines been checked against vibration
and possible failure?
9) Has the bin control been checked for correct setting
and operation?
10) Has the end user been given the instruction
manual, and instructed on how to operate the
icemaker and the importance of the recommended
periodic maintenance?
11) Has the end user been given the contact
information of an authorized service agent?
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