We have a Baxi boiler which has developed a fault which we can't seem to fix. The pilot light won't ignite when the system is cold. If you loosen the seal on the burner box to let some oxygen in then it fires up straight away and runs fine until the heating goes off, but then won't fire the next morning when cold. We've changed the fan, the gas detector, added a spacer behind the fan and had it serviced. Our heating engineer doesn't know what else it can be - any suggestions?

Dawn Turnbull, January 2011

Thank you for the suggestions. I have the plumber coming back on Saturday so will ask him to check all of these things whilst he is here and will let you know how I get on.

Dawn Turnbull, January 2011

check fan pressure switch it is probably sticking due to cold, damp conditions also worthwhile cleaning venturi tube as this could also cause the problems you've described

brian, January 2011

I think its a Baxi Solo II

Dawn Turnbull, January 2011

boiler flue restricted ,semi blocked ?.is thermocouple working ok and set at right gap from electrode ?

marti, January 2011

model of boiler ?

brian, January 2011