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Theory of Operation
Model 506 (UC Ice Maker)
Model 506 (UC Ice Maker)
3-8
#3752200 - Revision B - May, 2006
Operational Cycles
There are three operational cycles of the ice maker:
1. ICE MAKING
cycle
2. HARVEST cycle
3. CLEAN cycle
In addition, there are two operational OFF cycles of the
ice maker:
1. OFF cycle when bin is full of ice and service control
switch is turned to the “ON” position.
2. OFF cycle when the service control switch is turned
to the “OFF” position while power is still supplied to
the unit.
When the ice makers service control switch is in the
“ON” position, and the bin is not full of ice, the evapora-
tor thermostat determines whether the unit will be in the
ICE MAKING cycle or the HARVEST cycle.
The thickness control knob adjusts the evaporator ther-
mostat to sense different temperatures on the evapora-
tor freezing plate, which causes a different thickness of
ice.
ICE MAKING Cycle
In the electronic system, power is supplied through the
service control switch to the transformer, (which also
supplies power to the cutter grid and bin light through
the door switch), and through the bin thermostat to the
compressor.
Power is supplied through the evaporator thermostat to
the condenser fan and the water pump.
If an FSP condensate pump is installed on the unit,
power is supplied to the condensate pump through the
receptacle. The condensate pump operates when
needed through a pressure switch in the pump itself.
2
1
6
3
ON
OFF
CLEAN
SERVICE
SWITCH
115
VOLTS
60 HERTZ
N
L
WATER
PUMP
CONDENSER
FAN
START RELAY
COMPRESSOR
S
R
RECEPTACLE
HOT
GAS SOLENOID
N.C.
N.C.
WATER
VALVE
SOLENOID
SHUNT
EVAPORATOR
THERMOSTAT
2
3
1
BIN
THERMO-
STAT
OVERLOAD
TRANSFORMER
115 V
8.5 V
DOOR SWITCH
CUTTER GRID
UNIT SHOWN WITH GRAVITY DRAIN;
SERVICE SWITCH IN “ON” POSITION;
BIN NOT FULL OF ICE; NO DRAINAGE
WATER AT PUMP.
R
F
F
R
2
Figure 3-14. Ice Making Cycle
2
1
6
3
ON
OFF
CLEAN
SERVICE
SWITCH
115
VOLTS
60 HERTZ
N
L
WATER
PUMP
CONDENSER
FAN
START RELAY
COMPRESSOR
S
R
RECEPTACLE
HOT
GAS SOLENOID
N.C.
N.C.
WATER
VALVE
SOLENOID
SHUNT
EVAPORATOR
THERMOSTAT
2
3
1
BIN
THERMO-
STAT
OVERLOAD
TRANSFORMER
115 V
8.5 V
DOOR SWITCH
CUTTER GRID
UNIT SHOWN WITH FSP CONDENSATE;
PUMP; SERVICE SWITCH IN “ON”
POSITION; BIN NOT FULL OF ICE;
DRAINAGE WATER AT PUMP; IN ICE
MAKING CYCLE.
R
F
F
R
2
PLUG
PRESSURE
SWITCH
CONDENSATE
DRAIN PUMP
Figure 3-15. Ice Making with FSP Pump