Scotsman MF 52 S Manuel De Service page 9

output terminals for the leads of the ice maker
electrical wires.
The P.C. BOARD is the brain of the system and it
elaborates, through its micro processor, the signals
received from the sensors in order to control the
GREEN LIGHT
YELLOW LIGHT (steady)
(bleanking) Unit in shut-off procedure at full storage bin (I/R beam cutted)
YELLOW LIGHT
RED LIGHT (steady)
(bleanking) 3 minutes delay time at start up
YELLOW LIGHT (steady)
(bleanking) Unit shut-off due to a too hi-evaporating temp. >-1°C after 10 min of operation
The P.C. Board has also three small jumpers which
work as described in details here below.
The JP1 (TEST) is used ONLY on the factory allows
to make a rapid auto-diagnosis (when plug in) of the
P.C. Board outputs to liquid solenoid valve and gear
motor, by energising them in rapid sequence (2
seconds) one at the time, to make sure of their
operation.
DURING THE AUTOMATIC OPERATION OF THE
ICE MAKER THE JUMPER MUST BE REMOVED.
WARNING. This
performed in the shortest possible time in order
to avoid frequent starts and stops of the electrical
components which may cause damages to their
windings and controls.
The JP2, when closed, allows the skipping of the 3
minutes delay period at every start-up of the Ice
Maker.
NOTE. To prevent that the unit be subject to starts
and stops in rapid
recommended to keep these contacts always open..
The JP3 on model MF 52-62 is not used and can be
open or closed without any operating problem.
The I/R trimmer is used to modify a little the current
transmitted by the Infrared Optical Ice Level Control
to the PC Board.
NOTE. When change the setting, it is IMPERATIVE
to check up the correct operation of the Ice Level
Control filling up the vertical ice chute/s with flaker ice
till it break the Infrared beam between transmitter and
nd
receiver (2 YELLOW LED blinking). DO NOT USE
HANDS.
INTERFACE P.C. BOARD (Only on MF 62 Model)
Used only on MF 62 model, it allows to elaborate the
signal received from one of the two gear motor
rotation/direction sensors as well as from one of the
Unit under electrical power
Unit shut-off at full storage bin
Unit shut-off due to a too low-water level into float tank
Unit shut-off due to a too low-ambient temperature <+1°C
Unit shut-off due to the wrong rotation direction of gear motor
Unit shut-off due to the too low speed of gear motor
auto-diagnosis must
sequence it is
operation of the different electrical components of the
ice maker (gear motor, solenoid valve, etc.).
The five LEDS, placed in a row in the front of the P.C.
BOARD, monitor the following situations:
two ice bin level light controls transmitting it to the
P.C. Board for the control of the unit operation.
In practical terms the Interface P.C. Board is
equipped by four INLET sockets (two for the drive
motor rotation/direction sensors and two for the ice
level controls) and two OUTLET plugs connected to
the unit P.C. Board.
EVAPORATOR TEMPERATURE SENSOR
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
be
out from the evaporator and signals it by supplying 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.
In case the evaporating temperature, after 10
minutes from the unit start-up, does not go below -
1°C (30°F) due to shortage of refrigerant in the
system or due to the excessive condensing
temperature, the evaporator sensor signal reaching
the microprocessor is such to stop immediately the
unit operation, with the 5th Warning YELLOW LED
strongly
that blinks.
FLOAT RESERVOIR WATER SENSOR SYSTEM.
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 making use of its electrical
resistance.
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 resistance to the
current flow (conductivity lower than 30 µS) this
sensor system causes the shutoff of the machine.
In this situation the YELLOW LED will glow to warn
of the machine shutoff and the reason why.
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