Harvest Cycle; Electrical Sequence; Components Description - Scotsman EC 46 Service Manual

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OPERATION - ELECTRICAL SEQUENCE
The following charts illustrate which switches
and components are ON or OFF during the two
phases of the icemaking cycle.
Refer to the wiring diagram for reference.
FREEZING CYCLE
Electrical components
Compressor ............................................
Water Pump ...........................................
Fan Motor (Air cooled only) ....................
Hot Gas Valve ........................................
Inlet Water Valve ....................................
Electrical Controls
Evaporator Thermostat (contacts 3-4) ...
Evaporator Thermostat (contacts 3-2) ...
Bin Thermostat .......................................

HARVEST CYCLE

Electrical components
Compressor ............................................
Water Pump ...........................................
Fan Motor (Air cooled only) ....................
Hot Gas Valve ........................................
Inlet Water Valve ....................................
Electrical Controls
Evaporator Thermostat (contacts 3-4) ...
Evaporator Thermostat (contacts 3-2) ...
Bin Thermostat .......................................
Freeze Cycle
Average Discharge Pressure
7 ÷ 11 bars (100÷155 psig)
A/C:
Average Discharge Pressure
8.5 ÷ 10 bars (120÷140 psig)
W/C:
Suction Pressure
End Freeze Cycle: 0 ÷ 0.1 bar (0 ÷ 1.5 psig)
REFRIGERANT METERING DEVICE:
capillary tube
REFRIGERANT CHARGE (R 134 A)
Model Air cooled
EC 46 260 gr ( 9.5 oz.)
EC 56 260 gr ( 9.5 oz.)
EC 86 280 gr (10.0 oz.)

COMPONENTS DESCRIPTION

A.
The water pump operates continually throughout
the freezing cycle.
The pump primes the water from the sump to the
spray system and through the spray nozzles
sprays it into the inverted cup molds to be frozen
ON OFF
into crystal clear ice cubes.
•
•
B.
•
•
The water inlet solenoid valve is energized only
•
during the defrost cycle.
When energized it allows a metered amount of
incoming water to flow over the evaporator cavity
CLOSE OPEN
to assist the hot gas in defrosting the ice cubes.
•
The water running over the evaporator cavity
•
drops by gravity, through the dribbler holes of the
platen, into the sump.
•
On water cooled versions the water inlet solenoid
valve has one inlet and two outlets with two
separate solenoids energized the first (ice
productioon) by the contacts 3-2 of the evaporator
ON OFF thermostat and the second (water cooled
•
condenser) by a specific hi pressure control.
•
•
C.
•
The hot gas solenoid valve consists basically in
•
two parts: the valve body and the valve coil.
Located on the hot gas line, this valve is energized
by the contacts 3-2 of the evaporator thermostat
CLOSE OPEN
during the defrost cycle.
•
During the defrost cycle the hot gas valve coil is
•
activated so to attract the hot gas valve piston in
•
order to give way to the hot gas discharged from
compressor to flow directly into the evaporator
serpentine to defrost the formed ice cubes.
D.
The bin thermostat control body is located in the
front of control box behind the front louvered
panel.
The thermostat sensing tube is located into a
bulb holder on the side wall of the ice storage bin
where it automatically shuts the icemaker OFF
when in contact with the ice and re-starts the
icemaker when the ice is removed. Factory
settings are 1°C (35°F) OUT and 4°C (39°F) IN.
E.
The cube size control (evaporator thermostat)
body is located in the front of control box behind
Water cooled
the front louvered panel; it's basically a reverse
acting temperature control which closes the
250 gr (9.0 oz.)
contacts 3-2 when its temperature decreases
250 gr (9.0 oz.)
and closes the opposite contacts 3-4 when the
250 gr (9.0 oz.) temperature rises.
WATER PUMP
WATER INLET SOLENOID VALVE -
3/4 MALE FITTING
HOT GAS SOLENOID VALVE
BIN THERMOSTAT
CUBE SIZE CONTROL (EVAPORATOR
THERMOSTAT)
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