Scotsman AC-EC 107, Service Manual

Page: 38 / 48

Page 38
Page 38
O. WATER INLET SOLENOID VALVE -
3/4 MALE FITTING
(AC/EC 47-57-87-107 only)
A second water inlet solenoid valve is used on
water cooled version. An automatic hi pressure
control activates the coil of the water inlet solenoid
valve so to supply a metered amount of water to
the condenser and drop down its temperature
and pressure.
P. 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 as well as 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 compressor to flow directly
into the evaporator serpentine to defrost the
formed ice cubes.
Q. FAN MOTOR (Air 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.
R. 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.
S. HI PRESSURE CONTROL
(AC/EC 47-57-87-107 only)
Used only on the water cooled versions it operates
to keep between 9.5 and 10.5 bars (135
÷
150
psig) the hi-side or discharge pressure of the
refrigerant system by energizing the coil of the
water inlet solenoid valve that control the cooling
water flow to the condenser.
T. WATER REGULATING VALVE
(AC/EC 127-177 only)
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.
U. WATER DRAIN SOLENOID VALVE
(AC/EC 127-177 only)
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 15 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.