517672
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2
ELECTRONICS
2.1
Control Module
The electronic control module is situated in the unit compartment. It is connected to 220-240 volt
supply for switching of the compressor, defrost heater and PC fan. The compressor is switched
through a solid state Triac and relay, and the defrost heater through a relay. The compressor has
an external overload. The defrost and PC sensors are located on the front fan motor panel and
above the evaporator. A variable resistor replaces the thermostat, and is used to cycle the
refrigerator. The defrost timer has also been replaced by the control module.
2.2
Light Operation
The light globe remains at 230Volts 15 watt and is switched using the same light switch
mechanisms as with previous models, the plunger being depressed by the dairy cover to turn the
light on and off. The control module measures the current drawn from the light to determine
whether the door is opened or closed.
2.3
Temperature Controller
The temperature controller is a variable resistor located in the control box. It has replaced the
thermostat. The resistance range of this resistor is 0
Ω to 1KΩ. The evaporator temperature range
varies between
–15.5ºC at the lowest setting of 1, and -24ºC at the highest setting of 7. Mid
setting is -18ºC.
2.4
Beeper/Alarm
This is a piezo electric device located in the control module to provide the user with feedback on
fault alarms. If a fault occurs, the alarm only sounds when the door is opened. It turns off when
the door is closed.
2.5
Temperature Sensors
These are temperature-sensing devices, the resistance of which change with respect to
temperature. They have a single connector on the printed circuit board to ensure the integrity of
the resistance of the sensor is measured. Two sensors are located in the product. The PC sensor
is located in a pocket attached to the fan support to the left of the fan. The Defrost sensor, is
located on the under side of the evaporator.
