Saunier Duval problem

[gav1987]

3rd time lucky hopefully, all u gas engineers/plumbers
i have a sounier deval boiler, i had heating yesterday but no hot water, i get home today n now nothing, seems like there is no electric gettin to it, ive changed the fuse but still nothing, fan doesnt start or fu*kall! there is a green light constantly on, normall wen it plays up that light turns red but its still green, any ideas?

 

[Agile]

You are not likely to get much help with your sour devil boiler.

Firstly you have added to a three year old thread and second nobody likes those old boilers!

Tony

 

[Slugbabydotcom]

Seeing as this is a split post I presume you are referring to the old SD 623?

Two of the things that used to go wrong on them that could be relevant.

1 Flow switch diaphragm. A right barrel of fun to get into. They used to go every year until they improved the rubber.
IIRC about three tricky circlips, Take the microswitch housing off and undo the big screw behind it. Diaphragm is in the cylinder behind where the screw came from.
When this was the problem you could often get it to work after a fashion by putting the bar to a mid position

2 Dry joints on the pcb. Slightly right of centre but while you have your soldering iron out just have a look about there may be more.