VC50SDD Installation &
Technician’s Manual
Page 38 of 46
The following checklist should be used to check that the controller is working. If any of the tests fail
the controller should be replaced.
Test
What to do if the test fails
1
Check that the controller passes power to the
compressor and capacitor.
Measure the PV voltage on connector J2. Measure the
voltage on the capacitor and compressor power
terminals on J2. These two should be no less than 0.5V
smaller than the PV voltage.
Replace the controller
2
Check that the controller is basically working.
Once the PV and compressor have been checked.
(Section 2 and 3). Normal operation of the control circuit
can be assessed:
Connect the PV and switch on. Open the fridge lid,
remove the basket and warm the temperature sensors
with your hand. Check that the compressor has started
and the Green LED on the front of the fridge is ON.
Temporarily disconnect J4. The compressor should stop
and the LED should be OFF.
Replace the control board.
4
Check that the thermostat is set to the right
temperature
:
There is no adjustment of the thermostat temperature
but it can be checked as follows:
Run the fridge and wait until the compressor stops
running. Don’t open the fridge lid. The temperature on
the display on the front of the fridge should be between
2.5 and 3.5C
The thermostat has been factory
set to ensure the correct
operation of the fridge over a very
wide range of operating
conditions.
If the compressor is not being
turned on or off at the right
temperature the control board
should be replaced.
Replacing the Dulas SDD controller
Switch the PV isolator off and disconnect the PV cables. make a note of the orientation of the SDD
controller. Unplug the connectors to the circuit board and prise back the white plastic clips on each
edge of the board to release it from the fridge chassis.
Install the replacement board with the same orientation. Plug in the cables to the controller,
reconnect the PV and switch on. If the fridge is working replace the metal ventilation grill.
