Scotsman CME1356 - Manual (Page 23)

Technicians Only: Harvest Cycle Operational Sequence
Harvest
The (air cooled model) fan is off.
The purge valve opens, and will remain open for
74 seconds.
The water pump shuts off, it will restart in less than
74 seconds, depending upon the Purge Level set.
The water pump restarts and pumps out water thru
the open purge valve until the valve closes.
The inlet water valve then opens for about 30
seconds to add some water.
During the Harvest Cycle, ice will be falling from
the evaporators and between the ice sensor’s
electric eyes. The AutoIQ Controller monitors the
ice falling and stays in the Harvest Cycle until ice
quits going thru the electric eyes.
The maximum harvest time is 14 minutes. The first
Harvest after a restart will be a long one to
establish a base line, then the actual time it took to
release the ice is used to determine the length of
the next harvest cycle.
If no cubes fall (or are sensed) by the end of
Maximum Harvest Time, the machine senses a
refrigeration error. If the next cycle also produces
a refrigeration error, the machine Shuts Down.
Note: The last harvest cycle before shutting off on
bin full is 6 minutes long.
The machine will not restart for 4 minutes after
switching off on Bin Full, unless the freeze button
is pressed.
Note: If during a Bin Full shut down, the machine
has not restarted for 12 hours, the compressor will
run for 30 seconds to clear the oil of refrigerant.
Continuous Run Time:
A unit that operates 24 hours a day 7 days a week
is too small for the user’s needs. To maintain
harvest integrity, the controller will extend the
harvest time to 6 minutes minimum every 15th
consecutive harvest cycle.
Bin Thermostat (for those units so equipped):
In normal ambients the thermostat will react to ice
on the bulb in a few seconds. Reaction after
removal will take about a minute under normal
conditions, and longer in colder rooms.
Stacked Units:
If the bottom unit is in harvest and receives a signal
from the top unit that it is also in Harvest, the
bottom unit will stay in harvest for about 6 minutes.
If the bottom unit is shut off, but its controller still
has power, the top unit may continue to operate. If
the bottom unit’s power is shut off, the top unit will
shut down on bin full at the end of the next cycle. If
the top unit’s power is shut off, it does not impact
the lower unit.
An error shut down on one unit does not affect the
other. Either may be switched off at the controller.
Diagnostic Lights and Manual Resets
The controller will shut the machine off if a
malfunction is sensed. The Controller will restart the
machine 2 times, with a 50 minute interval between
restarts. If a malfunction is still present after the
second restart, the machine will then shut off and
must be manually reset. During the restart interval,
the machine will be off and a diagnostic code
indicated.
The exception to this is lack of water. The machine
will always try to re-fill the reservoir every 20
minutes.
Diagnostic Code Table
If a Diagnostic
Light
Water Light
Refrigeration
Light
Blinks once and
repeats Water pump did
not start Very long ice
harvest
Blinks twice and
repeats
Lack of water fill No harvest of ice
Blinks three
times and
repeats
not used
High Discharge
Temperature
Is ON all the
time
Water valve
leaking thru
rapidly
Check for low
discharge
temperature or
long freeze cycle
Both On all the
time Check for thermistor set unplugged
or failed
CME1356 and CME1656
May 2000
Page 23