Microgenus GC no 47 116 14

[DP]

Went to this boiler. On board fuses are OK but boiler does not recognise HW or CH demand. Pump does not smell, nor is it turning. Whilst checking on board fuses, smelt burnt PCB around a power resister to left of two 2Amp fuses.

Spoke to MTs who suggest a replacement PCB will be required and also to replace the HW demand switch. Can anyone throw any light on why the HW demand switch cooks the board?

 

[Agile]

Did you try joining the DHW flow switch wires to see if that brings on the boiler? The flow SW seems to be a common failure point!

The earlier PCBs also have a design problem and have been replaced by a redesigned version. The failure was intermittent lock-outs though.

Tony