Scotsman MC 15 Service Manual page 25

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J. WATER INLET SOLENOID VALVE -
3/4 GAS MALE FITTING
The water inlet solenoid valve is activated by the
micro processor of the P.C. BOARD during the
first 5 minutes of water filling phase and as well
during the defrost cycle.
When energized it allows a metered amount of
incoming water to flow overt he evaporator cavity
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 reservoir where it will be
sucked by the water pump and primed to the
spray system.
K. HOT GAS SOLENOID VALVE
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
through the micro processor of P.C. BOARD
during the defrost cycle and as well during the
water filling phase.
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
the compressor to flow directly into the evaporator
serpentine to defrost the formed ice cubes.
L. FAN MOTOR (Alir cooled version)
The fan motor is controlled through the P.C.
BOARD and the TRIAC by the condenser tempe-
rature sensor. Normally it operates only during
the freezing cycle to draw cooling air through the
condenser fins.
In the second part of the freezing cycle, the fan
motor can run at intermittance as the condenser
pressure must be kept between two
corresponding head pressure values (13÷14 bars-
180÷195 psig).
M. COMPRESSOR
The hermetic compressor is the heart of the
refrigerant system and it is used to circulate and
retrieve the refrigerant throughout the entire
system. It compresses the low pressure
refrigerant vapor causing its temperature to rise
and become high pressure hot vapor which is
then released through the discharge valve.
N. WATER REGULATING VALVE
(Water cooled version)
This valve controls the head pressure in the
refrigerant system by regulating the flow of water
going to the condenser.
As pressure increases, the water regulating val-
ve opens to increase the flow of cooling water.
O. CONTACTOR
Placed outside of the control box it is controlled
by the P.C. BOARD in order to close or open the
electrical circuit to the compressor.
P. WATER DRAIN SOLENOID VALVE
The water drain solenoid valve, electrically
connected in parallel to the water inlet and to the
hot gas solenoid valves, is energized for all the
length of the defrost cycle.
By means of the water pump, that remains
energized for 30 seconds at the beginning of the
defrost cycle, it allows the drain out of all remaining
water (rich of minerals deposited during the
previous freezing cycle) from the sump tank.
By doing so it allows to the ice maker to make
every new freezing cycle with new fresh water,
avoiding thereby the accumulation of sediments
and scales, which soon or later will cause the
partial or total clogging of the water system on the
unit.
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