Manitowoc NEO UD0140A, Technician'S Handbook

Page: 69 / 260

Part Number 000014797 Rev02 05/18 69
SEQUENCE OF OPERATION
The On/Off button must be depressed and the ice damper
must be closed before the ice machine will start.
The following is the primary sequence of operation.
Software revisions will alter some of the timing sequences
and are noted in software revisions.
Initial Start-up From Shutoff
The dump valve energizes to purge any water in the water
trough down the drain. The harvest valve energizes to
equalize refrigerant pressures before the compressor
starts.
Freeze Cycle
Prechill - The refrigeration system chills the evaporator
before water flow over the evaporator starts. The water
inlet valve energizes during the prechill and remains on
until the ice thickness float switch is satisfied.
Freeze - Water flowing across the evaporator cools as
the freeze cycle progresses. (Software version 2.58 or
higher: The water pump turns off for 25 seconds and the
water inlet valve energizes for 7 seconds when the pump
restarts) Water flowing across the evaporator will start to
freeze and build ice on the evaporator. After a sheet of ice
has formed, the harvest float switch signals the control
board to start a harvest cycle.
Harvest Cycle
Any remaining water is purged down the drain as
refrigerant gas warms the evaporator. When the
evaporator warms, the sheet of cubes slides off the
evaporator and into the storage bin. If all cubes fall clear of
the ice damper the ice machine starts another freeze cycle.
The maximum harvest time is a total of 7 minutes.
If the bin switch does not activate within 3.5 minutes, the
harvest cycle extends another 3.5 minutes.