Manitowoc Ice QM45 Series - Manual (Page 33)

5-3
Before Calling for Service Section 5
SAFETY LIMITS
General
In addition to standard safety controls, the control
board has two built in safety limit controls which
protect the ice machine from major component
failures.
Safety Limit #1: If the freeze time reaches 60
minutes, the control board automatically initiates a
harvest cycle. If three consecutive 60-minute freeze
cycles occur, the ice machine stops.
Safety Limit #2: If the harvest time reaches 3.5
minutes, the control board automatically returns the
ice machine to the freeze cycle. If three consecutive
3.5 minute harvest cycles occur, the ice machine
stops.
Safety Limit Stand-By Mode:
The first time a safety limit shut down occurs, the ice
machine turns off for 60 minutes (Stand-by Mode).
The ice machine will then automatically restart to see
if the problem reoccurs. During the Stand-By Mode
the harvest light will be flashing continuously and a
safety limit indication can be viewed. If the same
safety limit is reached a second time (the problem has
re-occurred) the ice machine will initiate a safety
limit shut down and remain off until it is manually
restarted. During a safety limit shut down the harvest
light will be flashing continuously.
Determining Which Safety Limit
Stopped The Ice Machine
When a safety limit condition causes the ice machine
to stop, the harvest light on the control board
continually flashes on and off. Use the following
procedures to determine which safety limit has
stopped the ice machine.
1. Move the toggle switch to OFF.
2. Move the toggle switch back to ON.
3. Watch the harvest light. It will flash one or two
times, corresponding to safety limits 1 and 2, to
indicate which safety limit stopped the ice
machine.
After safety limit indication, the ice machine will
restart and run until a safety limit is exceeded again.
Safety Limit Notes
• A safety limit indication is completed before the
water pump starts. Water contacting the ice
thickness probe in the freeze cycle will cause the
harvest light to flash. Do not mistake a harvest
light flashing in the freeze cycle with a safety
limit indication.
• A continuous run of 100 harvests automatically
erases the safety limit code.
• The control board will store and indicate only one
safety limit – the last one exceeded.
• If the toggle switch is moved to the OFF position
and then back to the ICE position prior to
reaching the 100-harvest point, the last safety
limit exceeded will be indicated.
• If the harvest light did not flash prior to the ice
machine restarting, then the ice machine did not
stop because it exceeded a safety limit.