circuit card in boiler failed due to water ingress down back of boiler (baxi) which had apparently come from air intake side of flue. Plumber replaced card ok but could not explain why water had got down. Flue checked out ok. Boiler is upstairs and flue runs vertical through roof from boiler. This happened during heavy rain. Is fan on boiler strong enough to cause drawing in of rain into flue? Any ideas ,don't want it to happen again. Too costly!
