Hi guys,
I have a Saunier Duval Thelia 623 boiler.
It stopped working recently and on opening i noticed the fan had burnt out. So i duly replaced this. However, for some reason the fan now works fine but there is no Spark. So i replaced the Spark generator. Still nothing. All cables seem correct to me. I have tested it by seeing if there is Pilot flame (there is if i light it with match). However, if i activate the hot water via a kitchen/bathroom, even on pilot the boiler is NOT put into action. Nothing happens. Is the multi function control the problem? This is doing my head in. The transformer seems to be fine. So there's poer throughout (hence the fan works fine now). Please, any ideas? To summarise: When i press the button igntition button i get NO spark. when i manually light the pilot and turn on hot taps i get NO full flames.
Is this the electrode sensor problem? Thanks for your help.

G, November 2008

The boiler has a 'loss of water switch' which prevents the boiler from operating if there is no pressure ie you should have 1.5 bar pressure. If you dont have any pressure add some water into the loop gently for about 3 seconds until the pressure is 1.5 bar.

Mick, January 2009

did you have to remove any air pipes from the fan

b, November 2008