Table of Contents
Advertisement
Page 21
OPERATING CHARACTERISTICS
On air cooled models, during the freezing cycle,
the discharge pressure will slowly decline as the
unit freezes ice and at the same time the suction
pressure will also decline, reaching its lowest
point just before harvest. Compressor amps
experience a similar drop.
On water cooled models, the discharge pressure
is maintened during the freeze cycle between 8.5
and 10 bars (120÷140 psig) by the combination
of a pressure control and a water inlet solenoid
valve. However, suction pressure and compressor
amps will still decline as the machine freezes ice.
Freeze Cycle
Average Discharge Pressure
A/C:
7÷11 bars (100÷155 psig)
Average Discharge Pressure
W/C:
8.5÷10 bars (120÷140 psig)
Suction Pressure
End Freeze Cycle:
REFRIGERANT METERING DEVICE:
capillary tube
REFRIGERANT CHARGE (R 134 A)
Model
Air Cooled
ACM 45
250 gr (9.0 oz)
ACM 55
260 gr (9.3 oz)
0÷0.1 bar (0÷1.5 psig)
Water Cooled
250 gr (9.0 oz)
250 gr (9.0 oz)
COMPONENTS DESCRIPTION
A.
EVAPORATOR TEMPERATURE
SENSOR
The evaporator temperature sensor probe,
located in contact with the evaporator serpentine,
detects the dropping of the evaporator tempera-
ture during the freezing cycle and signals it by
supplying a current flow to the Micro Processor of
P.C. BOARD.
According to the current signal and to after how
long this is received, the Micro Processor may or
not give the consent to the ice maker to complete
the freezing cycle.
The low voltage current transmitted, from the
evaporator temperature sensor to the P.C.
BOARD, is signalled by the lighting up of the
fourth (Time T1) and fifth (Time T2) RED LED
placed in the front of the P.C. BOARD to inform
the service engineer, of the normal (regular)
progressing of the freezing cycle.
B.
ICE BIN LEVEL SENSOR
The ice bin level temperature sensor, secured to
one of the storage bin walls, stops the operation
of the entire ice maker only at the end of the
defrost cycle when its sensing probe (in contact
with the stored ice) reaches the temperature of
+2°C (35°F) lighting up, in the meantime, the
third RED LED.
Once the ice is removed from the sensing probe,
its temperature progressively rise up and as it
reaches the value of +4.5°C (40°F) the ice bin
level temperature sensor transmits a low voltage
current flow to the P.C. BOARD so to restart the
operation of the unit.
NOTE. The ice maker, after the interruption
of its operation due to the ice level control
cut-out always restarts from the beginnig of
the freezing cycle.
By changing the combination of the DIP SWITCH
Keys number 8 and 9 it is possible to change the
range of the ice level control temperature sensor.
This is shown on table D, keeping its cut out
temperature always at +2°C (35°F).
C.
P.C. BOARD (Data processor)
The P.C. BOARD, fitted in its plastic box located
in the front of the unit, consists of two separated
printed circuits one at high and the other at low
voltage integrated with a program selector; of six
aligned LEDS monitoring to the service engineer
the operation of the machine; of one DIP SWITCH
with ten keys; of input terminals for the leads of
the two sensor probes and of input and output
terminals for the leads of the ice maker electrical
wires.
Page 21
Advertisement
Table of Contents
