System Information
Overall:
•
Refrigerant: 8 oz R-134a
•
Compressor: Hermetic, 1300 BTUH,
•
Condenser: Forced draft
•
Fan blade: 5 blade, 7 inch
•
Evaporator: Inverted, 24 cube cells. Copper
cups attached to continuous serpentine
•
Metering device: Cap tube
•
Defrost method: Hot gas bypass with water
assist
•
Spray method: 6 water jets
•
Water charge: 40 ounces
•
Water valve: 115 volt solenoid, .19 GPM
•
Water fill time: Varies with harvest time &
purge setting
•
Spray pump: Pedestal type.
•
Drain pump: Magnetic drive, controlled by
pressure switch
•
Purge method: Overflow standpipe
•
Control method: Electronic
•
Cycle control: Ther timers
•
Freeze cycle timer: 10 minutes, + - 4
•
Harvest cycle timer: 20 seconds, + - 40
•
Cube size adjustment: Freeze timer change.
•
Harvest cycle adjustment: Harvest timer
change
•
Bin control: Thermostat. Opens on
temperature fall, Cut Out: 35 degrees F. Cut
In 45 degrees F. Range is adjustable.
Electrical Components:
•
Compressor
•
Fan motor
•
Spray pump motor
•
Drain pump motor
•
Drain pump switch
•
Inlet water solenoid valve
•
Hot gas valve
•
Transformer
•
Controller
•
Water sensor
•
Thermistor
•
Bin thermostat
Electrical Sequence:
A closed bin thermostat signals to the controller a
need for ice. The controller checks for water, if
water is needed , the controller opens the inlet
water solenoid valve to fill the reservoir. The hot
gas valve is open to equalize the system. When the
reservoir is full, the compressor, fan motor, water
pump are switched on. After 5 seconds the hot gas
valve shuts and ice making begins.
Water is sprayed up into the inverted cup mold. As
the water is cooled and ice begins to form in the
cups, the temperature of the evaporator will fall.
The freeze cycle continues until the temperature of
the thermistor attached to the evaporator outlet
tube falls to about zero degrees F. At that point the
controller starts a freeze cycle timer, whose default
time is 10 minutes. At the end of the freeze cycle's
timed portion the controller switches to the harvest
cycle.
The harvest cycle begins with the controller
stopping the water pump and fan motor. At the
same time it opens the hot gas valve and the inlet
water solenoid valve. The ice is released by the
combination of discharge refrigerant gas entering
the evaporator serpentine and warming up the
copper, plus the inlet water that flows to the
evaporator, floods across the plastic platen to
warm it up and be pre-chilled for the next cycle. Ice
cubes drop individually and harvest continues until
the thermistor attached to the suction line warms
up to about 50 degrees F. At that point a harvest
timer starts, whose default time is 20 seconds. At
the end of that time the harvest cycle ends and the
freeze cycle restarts.
Bin control.
The machine's on and off modes are regulated by a
bin thermostat. The cap tube for the bin thermostat
is in the tube that holds the scoop. The machine
will only begin ice making when the thermostat's
contacts close. If the contacts re-open before the
temperature of the evaporator drops below a preset
point, the machine will stop. If the temperature is
below that point when the contact s open, the
machine will continue through a complete cycle
and stop at the end of the harvest cycle.
March 2010
Page 17
CU50
Service Manual
