Technicians Only: Harvest Cycle Sequence & Other Notes
Harvest
The Purge Valve will be open for 74 seconds.
The water pump shuts off, it will restart before 74
seconds, the restart time is based on the Purge
Level Setting.
The pump restarts and pumps water out of the
reservoir until the purge valve closes.
The inlet water valve will stay on for about 30
seconds to add enough water to assist with
harvest.
The Hot Gas Valve will be open for the entire
length of the Harvest Cycle.
During the Harvest Cycle, ice will be falling from
the evaporators and between the ice sensor’s
photo-electric eyes. The Controller monitors how
long the ice falls and uses that time to determine
the next harvest cycle’s length.
The first Harvest after a restart will take about 6
minutes to establish a base line, then the time it
took to release that ice is used to determine the
next harvest cycle’s length.
The maximum harvest time is 14 minutes.
If no cubes fall (or are sensed) by the end of the
Maximum Harvest Time, the machine senses a
Refrigeration error. If the next cycle also produces
a Refrigeration error, the machine will shut down.
Note: The last Harvest cycle before shutting off on
Bin Full will be 6 minutes long.
Note: The machine will not restart for 4 minutes
after switching off on Bin Full, unless the Freeze
button is pressed.
Bin Full: The controller will switch on the
compressor for 30 seconds after 12 hours of off
time to keep refrigerant out of the compressor oil.
Single Phase: Power Interruptions:
If the power supply to a single phase unit is
interrupted for less than a second, a time delay
relay will keep the compressor from restarting until
30 seconds have passed. Because the controller
should still be operating.
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 every 15th consecutive
harvest cycle.
Bin Thermostat:
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 bottom unit.
An error shut down on one unit does not affect the
other.
Either one may be switched off at the controller
without impacting the other.
Diagnostic Light Code Table
If a Diagnostic
Light
Water Light
Refrigeration
Light
Blinks once and
repeats
Water pump will
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
CME1856W
November 2001
Page 23
