New Danfoss BD35F and BD50F compressors are equipped with an electronic diagnostic circuit although most refrigeration manufacturers do not provide the indicator light. A 10 mA light emitting diode (LED) can be connected between the + fan terminal and D terminal of the electronic module. If the electronic unit records an operational error the diode will flash a number of times. The number of flashes depends on what kind of operational error was recorded. Each flash will last ¼ second. After the actual number of flashes, there will be a delay with no flashes, so that the sequence for each error can be repeated every 4 seconds.

  5        Flashes: Thermal cut-out of electronic unit

If the refrigeration system has been too heavily loaded, or if the ambient temperature is too high,  the electronic  unit will run too hot.

  4        Flashes: Minimum motor speed error

             If the refrigeration system is too heavily loaded, the motor cannot maintain minimum speed 1800 rpm.

       3      Flashes: Motor start errors

               The r              Motor is blocked or the differential pressure in the refrigeration system is too high.

       2    Flashes: Fan over-current cutout

               The                 Fan loads the electronic unit with more than one amp   

                                      1 Flash: Battery protection cutout

           The voltage is outside the cutout setting.

 

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