Electrical Sequence - Scotsman CME650 Service Manual

Initial Start Up
11. Check harvest time. The machine will have
to harvest all of the cubes before it goes back
into the freeze cycle.
Cam Follower
Cam
Timer Shown In Harvest Position
Freeze
Increase the Harvest Time if there is less than 15
seconds of harvest time after the last cube has
fallen into the bin. The machine ships set at 2
minutes of harvest time.
Decrease the Harvest Time if there is much more
than 15 seconds of harvest time after the last cube
has fallen into the bin. Note: Harvest time is
dependent upon the water and air temperatures at
the ice machine. Colder air and water will result in
faster ice making, but longer harvest cycles. Do
NOT adjust harvest time too short, as this will case
a freeze up of the evaporators.
To Adjust Harvest Time:
1. Disconnect electrical power.
2. Locate time cam in control box.
3. Loose set screw holding the two halves of the
cam together, and rotate the front half to increase
or decrease the harvest portion of the cam (low
part).
4. Re tighten the set screw.
5. Reconnect power and check cube size of the
next cycle, as it may require adjustment after the
harvest time has been set.
12. Check operation of the bin control circuit by
holding ice on the bin control tube in the bin. This
simulates bin full and the ice machine should
switch itself off at the end of a harvest cycle.
13. Replace all the panels. The ice machine is now
ready for automatic operation..
Timer
Harvest
2
3
October 1994
Page 11

Electrical Sequence:

This describes the sequence through a complete
cycle.
Freeze Cycle:
During the first part of the freeze cycle, the ice
machine compressor, fan motor if air cooled, and
water pump are operating. The relay in the middle
of the circuit board is energized.
Timed Freeze:
Cube size control closes, connecting power to the
timer motor, and after a few (4.5-5.5) minutes this
timer opens the circuit to the relay on the circuit
board. This starts the harvest cycle.
Harvest:
In the harvest cycle, the water pump and
compressor stay operating, and these two valves
are energized:
Hot gas valve
Inlet water valve
The unit stays in the harvest cycle until the timer
has turned the cam which has pushed the timer
micro switch button IN. If the bin thermostat is
OPEN, the ice machine will stop. If the bin
thermostat is CLOSED, the relay will energize, and
the unit will make another batch of cubes.
CME650