Section 3
Ice Machine Operation
Part Number 000001114
3-3
HARVEST SEQUENCE
5.
Water Purge
The water pump continues to run, and the water dump
valve energizes for 45 seconds to purge the water in the
sump trough. The water fill valve energizes (turns on)
and de-energizes (turns off) strictly by time. The water fill
valve energizes for the last 15 seconds of the 45-second
water purge. The water purge must be at the factory
setting of 45 seconds for the fill valve to energize during
the last 15 seconds of the Water Purge. If set at less
than 45 seconds the water fill valve does not energize
during the water purge.
After the 45 second water purge, the water fill valve,
water pump and dump valve de-energize. (Refer to
“Water Purge Adjustment” for details.) The harvest valve
also opens at the beginning of the water purge to divert
hot refrigerant gas into the evaporator.
6.
Harvest
The harvest valve(s) remains open and the refrigerant
gas warms the evaporator causing the cubes to slide, as
a sheet, off the evaporator and into the storage bin. The
sliding sheet of cubes swings the water curtain out,
opening the bin switch. The momentary opening and re-
closing of the bin switch terminates the harvest
sequence and returns the ice machine to the freeze
sequence (Step 3 - 4.)
Figure 3-3. Harvest Sequence (Typical Q450 Shown)
AUTOMATIC SHUT-OFF
7.
Automatic Shut-Off
When the storage bin is full at the end of a harvest
sequence, the sheet of cubes fails to clear the water
curtain and will hold it open. After the water curtain is
held open for 7 seconds, the ice machine shuts off. The
ice machine remains off for 3 minutes before it can
automatically restart.
The ice machine remains off until enough ice has been
removed from the storage bin to allow the ice to fall clear
of the water curtain. As the water curtain swings back to
the operating position, the bin switch re-closes and the
ice machine restarts (steps 1 - 2), provided the 3 minute
delay period is complete.
Figure 3-4. Automatic Shut-Off (Typical Q450
Shown)
