Page 21
Page 21
PRINCIPLE OF OPERATION
How it works
In the SCOTSMAN Modular Cubers the water
used to make the ice is kept constantly in
circulation by an electric water pump which primes
it to the self propeller spray bar nozzles from
where it is diverted into the inverted mold cups of
the evaporator (Fig. B).
A small quantity of the sprayed water freezes into
ice; the rest of it cascades by gravity into the
sump assembly below for recirculation.
FREEZING CYCLE (Fig. A)
The hot gas refrigerant discharged out from the
compressor reaches the condenser where, being
cooled down, condenses into liquid. Flowing into
the liquid line it passes through the drier filter,
then it goes all the way through the capillary tube
(on MXG 328-428-438-638) and EXP valve on
MXG 938 where, due to the heat exchanging action,
it
looses some of its heat content so that its pressure
and temperature are lowered as well.
Next the refrigerant enters into the evaporator
serpentine (which has a larger I.D. then the
capillary) and starts to boil off; this reaction is
emphasized by the heat transferred by the
sprayed water.
The refrigerant then increases in volume and
changes entirely into vapor.
The vapor refrigerant then passes through the
suction accumulator (used to prevent that any
small amount of liquid refrigerant may reach the
compressor) and through the suction line. In both
the accumulator and the suction line it exchanges
heat with the refrigerant flowing into the capillary
tube (warmer), before to be sucked in the
compressor and to be recirculated as hot
compressed refrigerant gas.
The freezing cycle is controlled by the evaporator
temperature sensor (which has its probe in contact
with the evaporator serpentine) that determines
the length of its first portion of the cycle.
When the temperature of the evaporator serpentine
drops to a pre-set value, the evaporator sensor
probe changes its electrical resistance allowing
a low voltage current (12 volts) to flow to the P.C.
BOARD which in turn activates an electronic timer.
The timer, which is built-in the P.C. BOARD,
takes over from the evaporator temperature
sensor, the control of the freezing cycle up to its
completion.
NOTE.
The change of the electric potential of
the evaporator sensor with the consequent
activation of the timer (Time mode) is signalled
by the glowing-up of the RED LED located
beside the FREEZING yellow one in the front
of the P.C. BOARD.
MXG-S 328 A ON OFF ON ON OFF ON ON ON OFF ON
MXG-S 328 W - 230/60
OFF ON ON ON OFF ON ON ON OFF ON
MXG-M 328 A ON ON OFF ON OFF ON ON ON OFF ON
MXG-M 328 W ON ON OFF ON OFF ON ON ON OFF OFF
MXG-M 328 W - 230/60 ON ON OFF ON OFF ON OFF ON OFF OFF
MXG-L 328 A OFF OFF OFF ON OFF ON ON ON OFF ON
MXG-L 328 W OFF OFF OFF ON OFF ON ON ON OFF OFF
MXG-S 428-438 A ON OFF ON ON OFF ON ON ON OFF ON
MXG-S 428-438 W
MXG-M 428-438 A OFF OFF ON ON OFF ON ON ON OFF ON
MXG-M 428-438 W OFF OFF ON ON OFF ON ON ON OFF OFF
MXG-M 428-438 - 230/60
ON ON OFF ON OFF ON ON ON OFF ON
MXG-L 428-438 A OFF OFF OFF ON OFF ON ON ON OFF ON
MXG-L 428-438 W OFF OFF OFF ON OFF ON ON ON OFF OFF
MXG-S 638 A ON OFF ON ON OFF ON ON ON OFF ON
MXG-S 638 A - 230/60
ON OFF ON ON OFF ON ON ON OFF ON
MXG-S 638 W
MXG-M 638 A ON ON OFF ON OFF ON ON ON OFF ON
MXG-M 638 W ON OFF ON ON OFF ON ON ON OFF OFF
MXG-M 638 - 230/60 OFF OFF ON ON OFF ON OFF ON OFF ON
MXG-L 638 A OFF OFF OFF ON OFF ON OFF ON OFF ON
MXG-L 638 A - 400/50/3
OFF OFF OFF ON OFF ON OFF ON OFF ON
MXG-L 638 W OFF OFF OFF ON OFF ON OFF ON OFF OFF
MXG-L 638 W - 230/60
OFF OFF OFF ON OFF ON OFF ON OFF OFF
MXG-M 938 A ON ON OFF ON OFF ON OFF ON OFF ON
MXG-M 938 W ON ON OFF ON OFF ON OFF ON OFF OFF
MXG-L 938 A OFF OFF OFF ON OFF ON ON OFF OFF ON
TAB. A
DIP SWITCH FACTORY SETTING COMBINATIONS PER MODEL AND VERSION
DIP SWITCH
12345678910
FREEZING CYCLE
DEFROST
CYCLE
DEFR. CYCLE
ADD. TIME
15/30°
AIR
WATER
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