Ice Making Sequence Of Operation - Manitowoc S Installation, Use & Care Manual

Ice Making Sequence Of Operation

NOTE: The toggle switch must be in the ice position and
the water curtain/ice dampers must be in place on the
evaporator 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
Water flows across the evaporator and the refrigeration
system chills the evaporator. Ice builds on the
evaporator until water contacts the ice thickness probe.
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 water curtain (or ice damper) the ice machine
starts another freeze cycle.
Off Cycle
If the water curtain or ice damper are held open by ice
cubes the ice machine shuts off. When the water curtain
or 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.
Freeze lock is bypassed after moving the toggle
switch from OFF to ICE position for the first cycle
only.
• The maximum freeze time is 60 minutes at which
time the control board automatically initiates a
harvest sequence.
• The maximum harvest time is 3.5 minutes for single
evaporators and 7 minutes for multiple evaporator
model. The control board automatically initiates a
freeze sequence when these times are exceeded.
18
Section 3
Operation
SAFETY LIMITS
Safety limits are stored and indicated by the control
board after three cycles. The number of cycles required
to stop the ice machine varies for each safety limit.
• Safety Limit 1 all models - If the freeze time reaches
60 minutes, the control board automatically initiates a
harvest cycle. If 6 consecutive 60-minute freeze
cycles occur, the ice machine stops.
• Safety Limit 2 single evaporator models - If the
harvest time reaches 3.5 minutes, the control board
automatically returns the ice machine to the freeze
cycle. If 500 consecutive 3.5 minute harvest cycles
occur, the ice machine stops.
• Safety Limit 2 multiple evaporator models - If the
harvest time reaches 7 minutes, the control board
automatically returns the ice machine to the freeze
cycle. If 500 consecutive 7 minute harvest cycles
occur, the ice machine stops.
• Safety Limit 3 multiple evaporator models - If the low
refrigerant pressure control opens, the ice machine
shuts off and starts a 5 minute delay period. If 3
consecutive low pressure events occur, the ice
machine stops and flashes the harvest light.
Use the following procedures to determine if the control
board contains a safety limit indication.
1. Move the toggle switch to OFF.
2. Move the toggle switch back to ICE. Watch the
safety limit lights/harvest light on the control board. If
a safety limit has been recorded, the corresponding
light will blink once, twice or three times to indicate
which safety limit stopped the ice machine.
Part Number 000006520 11/11