VC50SDD Installation &
Technician’s Manual
Page 37 of 46
Section 4. Dulas SDD controller testing
If Section 2 and Section 3 have been completed and no problem has been found the problem is
likely to lie with the Dulas SDD controller. This controller provides the following:
•
Connections for the compressor, PV and capacitor (connector J2).
•
The refrigerator thermostat
There are two temperature sensors mounted on the right hand side at the top and bottom
of the vaccine storage compartment. When there is sufficient light for the PV array to allow
the compressor to run the Dulas SDD controller ensures that the average of these two
temperature sensors is maintained at 3.5C. As a fail-safe the compressor will turn off if the
lower temperature is below 3C, even if the average temperature is higher than 3.5C.
•
Control of the green LED on the front panel
The front panel LED will illuminate to signify that the compressor is running.
If there is enough solar power the compressor will usually run for a few hours at the start of
the day and then run intermittently after that to maintain the correct internal temperature.
