Ice Making Sequence Of Operation; Safety Limits - Welbilt Manitowoc NEO UDF0140A Installation, Operation And Maintenance Manual

Operation

Ice Making Sequence of Operation

NOTE: The On/Off button must be depressed and the ice
damper must be closed before the ice machine will start.
Water Purge Cycle
The ice machine purges any remaining water from the water
trough down the drain.
Freeze Cycle
Prechill - The refrigeration system chills the evaporator
before water flow over the evaporator starts. The water inlet
valve energizes during the pre-chill and remains on until the
ice thickness float switch is satisfied.
Freeze - Water flowing across the evaporator cools as the
freeze cycle progresses. When the water temperature
reaches setpoint, the water pump will de-energize for 25
seconds, then restart. 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.
Full Bin Cycle
If the ice damper is held open by ice cubes, the ice machine
shuts off. When the ice damper closes, the ice machine starts
a new cycle at the water purge.
Control Board Timers
The control board has the following non-adjustable timers:
• The ice machine is locked into the freeze cycle for 6
minutes before a harvest cycle can be initiated.
• The maximum freeze time is 45 minutes, at which time
the control board automatically initiates a harvest
sequence.
• The maximum harvest time is 7 minutes. When harvest
is complete the control board automatically initiates a
freeze sequence.
• If the ice damper does not open and close within the
7 minute harvest cycle, the ice machine enters a water
thaw cycle for 170 seconds. If the damper does not open
and close within the 170 second thaw cycle, a second
thaw cycle starts. The control board automatically
initiates a freeze sequence when the thaw cycle(s) is
complete.
16

SAFETY LIMITS

Safety limits are stored and indicated by the control board.
The number of cycles required to stop the ice machine varies
for each safety limit.
Safety limits can be reset by pressing the On/Off button and
starting a new ice making cycle.
A safety limit is indicated by an energized Service Light on
the touch pad. Refer to Section 5 if you receive a safety limit
indication.
• Safety Limit 1 - If the freeze time reaches 45 minutes,
the control board automatically initiates a harvest cycle.
After 6 consecutive 45-minute freeze cycles occur, the ice
machine stops.
• Safety Limit 2 - If the harvest time reaches 3.5 minutes,
the control board automatically energizes the water
pump and extends the harvest cycle another 3.5 minutes
(7 minutes total). If the ice damper does not open and
close within the 7 minute harvest cycle, the ice machine
enters a water thaw cycle for 170 seconds. If the damper
does not open and close within the 170 second thaw
cycle, a second thaw cycle starts. The control board
automatically initiates a freeze sequence when the thaw
cycle(s) is complete. If 3 consecutive 7 minute harvest
and thaw cycles occur, the ice machine stops.
• Safety Limit 3 - If the freeze time reaches 4 minutes
and water is not sensed, the ice machine stops and
initiates a 30 minute delay period. The ice machine will
automatically restart at the end of the 30 minute delay
period. If 100 consecutive failures occur, the ice machine
stops.
Part Number: 040005890 Rev 01 06/18
Section 3