Component Description - Scotsman MDT2C12 User Manual

COMPONENT DESCRIPTION

A. EVAPORATOR TEMPERATURE SENSOR -
BLUE 2 POLE 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 of the evaporator and signals it by
supplying a low voltage current flow to the PC
Board microprocessor. According to the current
received, the microprocessor lets the ice machine
to continue its operations or not. If within 10
minutes of startup the evaporating temperature
does not go below 30°F the evaporator sensor
signals the microprocessor to stop the unit
operation immediately and causes the 3rd
WARNING YELLOW LED to blink.
B. WATER LEVEL SENSOR - RED TWO POLE
CONNECTOR – AUTOMATIC RESET
This sensor system consists 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 PC Board. When the
cover of the reservoir is positioned properly the tips
of both rods dip into the reservoir water and signal
its presence by supplying power to the PC Board.
NOTE: In the event of shortage of water in the
reservoir or if the water used is too soft
(de-mineralized) to cause greater resistance to the
current flow (conductivity lower than 30mS) this
sensor system causes the machine to shutoff to
protect it from running with an interrupted or
inadequate water supply.
When this happens the 5th YELLOW LED will turn
on warn that the ice machine is off and why.
C. CONDENSER TEMPERATURE SENSOR -
BLACK TWO POLE CONNECTOR –MANUAL
RESET
The condenser temperature sensor probe (located
within the condenser fins) detects condenser
temperature variations and signals them by
supplying current, at low voltage, to the PC
BOARD.
Current to the microprocessor on the PC Board
varies and as it does the microprocessor supplies,
through a TRIAC, power at a high voltage to the
fan motor so that it can cool the condenser and
reduce its temperature.
If the temperature rises to 158°F or above the
current sent to the microprocessor causes the
machine to cease operation and turns on the 2nd
RED WARNING LED.
NOTE: After fixing the problem that caused the
high condenser temperature, press the RESET
button or turn the power line main disconnect
switch OFF and ON to restart the unit after the shut
down.
The fan motor will cycle on an off to maintain the
discharge pressure.
D. GEAR MOTOR ROTATION AND SPEED
SENSOR - RED FOUR POLE CONNECTOR -
MANUAL RESET
This safety device is housed on top of the Drive
Motor and detects - based on the Hall Effect
principle - the rotating speed and rotating direction
of the drive Motor. Should the rotating speed drop
below 1300 rpm the magnitude measured by this
device signals the microprocessor to stop the unit
and turns on the 3rd YELLOW LED. The same
reaction occurs when the drive motor rotates in the
wrong direction (counterclockwise) or it doesn't
rotate at all.
NOTE: After diagnosing and eliminating the
problem that caused the intervention of the safety
device, press the RESET button or turn the power
line main disconnect switch OFF and ON to restart
the unit after the shut down.
May 2002
Page 15
MDT2