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Model 506 (UC Ice Maker)
Model 506 (UC Ice Maker)
Theory of Operation
3-9
#3752200 - Revision B - May, 2006
Figure 3-16. Harvest Cycle
HARVEST Cycle
When the set temperature of the evaporator thermostat
is reached, the evaporator thermostat terminates power
to the fan and water pump, and supplies power to the
hot gas valve solenoid and the water fill valve solenoid.
On units where the shunt is still in the receptacle, the
power is supplied to the solenoids through the shunt.
In units supplied with an FSP condensate pump
installed, power is supplied to the condensate pump
through the receptacle. The condensate pump runs
continuously during the HARVEST cycle.
Power is supplied to the solenoids through the conden-
sate pump circuits. If the pressure switch in the con-
densate pump senses that the pump is not operating
properly (pumping out the water), the switch opens,
turning on the pump, and terminating power to the sole-
noids, thereby stopping the HARVEST cycle.
When the evaporator temperature rises, because of the
hot gas flow and because the ice slab has slid off, the
evaporator thermostat switches the unit to the ICE
MAKING cycle. This cycling, between the ICE MAKING
cycle and the HARVEST cycle, continues until the ice
bin is full.
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; IN HARVEST
CYCLE.
R
F
F
R
PLUG
PRESSURE
SWITCH
CONDENSATE
DRAIN PUMP
HOT
2
Figure 3-17. Harvest Cycle with FSP Pump
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
HARVEST CYCLE.
R
F
F
R
PLUG
PRESSURE
SWITCH
CONDENSATE
DRAIN PUMP
HOT
