Ice Making Sequence Of Operation; Initial Start-Up - Manitowoc UG Series Installation, Operation And Maintenance Manual

Section 3

Ice Making Sequence of Operation

INITIAL START-UP

1. Water Inlet and Pressure Equalization
Turn the toggle switch to "ON" position. The water fill
valve and harvest valve are energized. 300 seconds
later, the water fill valve is de-energized. 20 seconds
after the harvest valve solenoid is energized, the
compressor is energized. 300 seconds after the
compressor is energized, the harvest valve solenoid is
de-energized, the water pump and the fan motor are
energized, and the machine goes into freeze cycle.
2. Freeze Cycle
The pump sprays water into the inverted cups. The
water freezes layer by layer, until an ice cube forms in
each cup.
When the "water temperature" is equal to or less than
2°C for more than 5 seconds, the control will read the
"liquid line temperature" and dip switch setting, and give
the "freeze postpone time" and "fan shut-off time". The
board will shut off the fan before the end of the freeze
cycle to assist harvest. When the freeze postpone time
has elapsed, the harvest cycle is initiated.
Part Number: 040003628 Rev. 01 01/14/18
3. Harvest Cycle
The compressor continues to operate and the water
pump is de-energized. The hot gas valve energizes,
allowing hot gas to enter and warm the evaporator. The
water valve is also energized, aiding with harvest, as
well as filling up the sump with fresh water for a new
freeze cycle.
At the point of 2 minutes to freeze end, the board will
read the "liquid line temperature" again and calculate
the "harvest time".
The ice falls from the cups and is directed into the bin
by the ice chute. The harvest cycle continues until the
harvest time has elapsed, then machine goes into a
new freeze cycle.
4. Automatic Shut-Off
When the storage bin is full, the ice will come in contact
with the bin thermostat which is located inside the bin.
The machine will stop after approximately 45 seconds of
continuous ice contact with the bin thermostat probe.
The ice machine remains off until a 3-minute delay
has elapsed and enough ice has been removed from
the storage bin to allow the ice to fall clear of the bin
thermostat probe. As the ice clears the probe, the bin
thermostat warms up and the machine starts another
freeze cycle.
Operation
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