Components Description - Scotsman DXN 207 Service Manual

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COMPONENT DESCRIPTION
A. EVAPORATOR TEMPERATURE
SENSOR - BLACK 2 POLES CONNECTOR
- MANUAL RESET
The evaporator sensor probe is inserted into its
tube well, which is welded on the evaporator
outlet line. It detects the temperature of the
refrigerant on the way out from the evaporator
and signals it by suppying a low voltage current
flow to the P.C. Board Micro-Processor.
According to the current received, the micro-
processor let the ice maker to continue its
operations or not. In case the evaporating tem-
perature, after 10 minutes from the unit start-up,
does not go below 0°C (32°F) the evaporator
sensor signal reaching the microprocessor is
such to stop immediately the unit operation, with
the AØ2 Alarm Code on display.
B. WATER LEVEL SENSOR - RED TWO
POLES CONNECTOR - AUTOMATIC
RESET
This sensor system consist of two small stainless
steel rods vertically fitted on the inner face of the
reservoir cover and electrically connected to the
low voltage circuit of the P.C. Board. When the
cover of the reservoir is positioned in its place the
tips of both the rods dip into the reservoir water
and detects and signals its presence by supply
power back to the P.C. Board.
NOTE. In the event of shortage of water in
the reservoir or, in case the water used is too
soft (de-mineralized) to cause greater
resistence to the current flow (conductivity
lower than 30 µ S) this sensor system causes
the shutoff of the machine, to protect it from
running with an interrupted or inadequate
water supply.
In this situation the AØ1 alarm code on
display will glow to warn of the machine
shutoff and the reason why.
C. CONDENSER TEMPERATURE SENSOR
- WHITE TWO POLES CONNECTOR -
MANUAL RESET
The condenser temperature sensor probe,
located within the condenser fins detects the
condenser temperature variations and signals
them by supplying current, at low voltage, to the
P.C. BOARD.
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 that it can cool the condenser
and reduce its temperature.
In the event the condenser temperature rises
°
and reaches 70 C the current arriving to the
micro processor is such to cause an immediate
and total stop of the machine operation with the
glowing of the AØ3 Alarm Code on display.
NOTE. To restart the unit after the shutoff
caused by the hi condenser temperature, it
is necessary (after having remedied to the
causes of unit stoppage) to switch OFF and
ON the power line main disconnect Switch.
D. GEAR MOTOR ROTATION AND SPEED
SENSOR - RED FOUR POLES
CONNECTOR - MANUAL RESET
This safety device is housed on top of the Drive
Motor and detects - based on Hall Effect principle
- the rotating speed and rotating direction of the
drive Motor.
Should the rotating speed drop below
1300 r.p.m. the magnitude measured by this
device is such to signal to the microprocessor to
stop the unit and light-up A1Ø Alarm Code. The
same reaction occures when the drive motor will
tend to rotate in the wrong direction
(counterclockwise) or it doesn't rotate at all.
NOTE. To restart the unit after the shutoff
caused by this safety device, it is necessary
first to eliminate the cause that has generated
the intervention of the device and switch
OFF and ON the power line main disconnect
switch.
E. ICE LEVEL CONTROL – BLACK FOUR
POLES CONNECTOR – AUTOMATIC RESET
The electronic ice bin level control, located under
the plastic bin cover, has the function to stop the
operation of the ice machine when the light beam
between the light source and the sensor gets
interrupted by the ice which accumulates in the
spout. When the light beam gets interrupted for
as long as 10 seconds, the compressor stops
immediately and the drive motor keeps on working
by 3' delay then stops. On the display appears
BF1 code to monitor the full ice bin situation. The
10 seconds of initial delay prevents that any
minimum interruption of the light beam due to the
regular ice chuting through the ice spout may
stop the operation of the unit. As soon as the ice
is dispensed out with the resumption of the light
beam for 10 seconds between the two infrared
sensor of ice level control a BF2 code appears
on display. After that, the unit resume its operation
with the standard starting delay.
AUTOMATIC CALIBRATION OF THE ICE
LEVEL CONTROL
The P.C. BOARD performs the Automatic
Calibration with the Infrared Optical Ice Level
Control at any start-up of the machine through
the ON/OFF Green Push button except when the
bin is already full of ice during the restart.
Every time power is provide to the PC Board, it
checks automatically the physical condition of
the Optical Ice Level Control and self-adjust the
current transmitted so to assure the correct
operation of the Optical Ice Level Control.
FØ2 will appear on display during this phase.
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