Component Description - Scotsman ACM 85 Service Manual

OPERATING CHARACTERISTICS
ACM 85, AC 125 and AC 175
Freeze Cycle
Average Discharge
Pressure A/C: 9.5÷8.5 bars (130÷110 psig)
Average Discharge
Pressure W/C:
Suction Pressure
End Freeze Cycle:
AC 225
Freeze Cycle
Average Discharge
9.15 ÷ 17 bars (210÷240 psig)
Pressure A/C:
Average Discharge
Pressure W/C:
Suction Pressure
End Freeze Cycle:
REFRIGERANT CHARGE (R 134 A)
Air cooled
ACM 85 290 gr (10.2 oz.)
AC 125 450 gr (15.9 oz.) 300 gr (10.6 oz.)
AC 175 450 gr (15.9 oz.) 330 gr (11.6 oz.)
REFRIGERANT CHARGE (R 404 A)
Air cooled
AC 225 620 gr (22 oz.)
9 bars (125 psig)
0 ÷ 0.1 bar (0 ÷ 1 psig)
17 bars (240 psig)
1.7 bar (24 psig)
Water cooled
250 gr (8.8 oz.)
Water cooled
450 gr (16 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 received, the micro
processor supplies power to the electronic timer
built into the P.C. BOARD so that it takes control
of the length of the 2nd phase of freezing cycle.
The length of the timed phase is pre-fixed by the
setting of the keys 1, 2, 3 and 4 of the DIP
SWITCH.
The activation of the electronic timer is indicated
by the lighting up of the RED LED placed in the
front of the P.C. BOARD.
This lighting up occures usually in the mid period
of the freezing cycle and signals the switching
from the first to the second phase of the freezing
cycle.
NOTE. Whenever, after 15 minutes from the
beginning of the freezing cycle, the
evaporating temperature have not yet
reached the value of 0 ° C (32 ° F), the
P.C.Board switches OFF the machine with
the BLINKING of RED LED.
B. CONDENSER TEMPERATURE SENSOR
The condenser temperature sensor probe,
located within the condenser fins (air cooled
version) or in contact with the tube coil (water
cooled version) detects the condenser tempe-
rature variations and signals them by supplying
current, at low voltage, to the P.C. BOARD.
In the air cooled versions, in relation to the
different current received, the micro processor of
the P.C. BOARD supplies, through a TRIAC, the
power at high voltage to the fan motor so to cool
the condenser and to reduce its temperature.
In case the condenser temperature rises and
reaches 75°C (170°F) - on air cooled models - or
62°C (145°F) - on water cooled models - the
current arriving to the micro processor is such to
cause an immediate and total stop of the machine
operation.
C. AMBIENT TEMPERATURE SENSOR
The probe of this sensor, located in the front of
the ice maker condenser (Air cooled version) and
on the water supply line to the condenser (Water
cooled version) has the function to detect the
ambient or the water temperature and by changing
its own electrical resistance supplies a different
current flow to the P.C. BOARD.
This different current flow received by the
P.C.BOARD, is elaborated by the micro processor
in order to extend or shorten the defrost cycle
length (longer in cold ambient situations, shorter
in warm ones).
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