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1.3 Condenser Layout
The compressors have no oil cooler lines; therefore the re-routing of the condenser is as follows:
Discharge line from the compressor runs directly to the condenser on the back panel. From the
back panel it enters the base panel, then through the left-hand side condenser, into the right-hand
side condenser, then to the filter dryer capillary. The remaining circuit layout remains unchanged.
1.4 Suction Line Assembly
The accumulator has been incorporated into the Showa evaporator assembly, therefore the
accumulator inside the insulating foam has been removed. This has, in effect, removed three
internal welds and replaced them with two external welds (above the evaporator assembly). The
suction line assembly now has exposed ends at the unit compartment and the FC compartment.
1.5 Bottom Step Evaporator
With the new electronics and thermistor temperature control, the bottom step evaporator has been
made redundant. This also has the effect of removing a further two internal welds (inside the
insulating foam) from the unit.
2 ELECTRONICS
2.1 Control Module
The electronic control module is situated in the unit compartment. It is connected to mains supply
and switches the compressor, defrost heater and FC fan motor. The compressor is switched
through a solid state Triac and relay, and the defrost heater through a relay. The compressor has
an external overload and relay fitted. The defrost and FC sensors are located above the
accumulator and on the rear duct. A variable resistor, which replaces the temperature controller, is
used to cycle the freezer. The defrost timer has also been replaced by the electronics in the
control module.
2.2 Temperature Controller
The temperature adjustment is a variable resistor located on the control module at the rear of the
cabinet. The FC evaporator temperature range varies between –12ºC at the warmest setting of 1
and -24ºC at the coldest setting of 7. Between 3 and 4 is the mid factory setting (approx is -18ºC).
2.3 Temperature Sensors
These are thermistors whose resistance changes 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 within the FC compartment. The FC sensor is located in the
centre of the duct panel above the evaporator and senses the temperature for switching the
compressor on and off. The defrost sensor is located immediately above the FC evaporator
accumulator. Its only job is to terminate the defrost (switch off the defrost element) once the
sensor reaches +8º C.
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