Freash air intake?

I have the same model boiler and have had the same problem for the last two years.I have replaced both DHW and CH temperature sensors,replaced the overheat safety thermostat,cleaned fan contacts,cleaned venturi,blown through the air pressure switch pipes and scratched my head a heck of a lot!
But still the only way of getting the boiler to run correctly is to remove the front of the combustion chamber. Obviously the problem is down to air/CO2 mixture or purely a lack of airflow.
Jim didn't say whether replacing the fan cured the problem!
I'm interested to see any other suggestions.I'll certainly post the solution when I find it.Good luck

Rupert
March 2009

Thanks jim i checked extract fan and everything seems ok ,just down loaded manufactures manual it seems the flue lengths are within max allowed i think i,ll check fresh air flue is clear.

paul
February 2009

this is one of the worst boilers made but it sounds like a fault i had recent which turned out to be the venturi part of the fan had fallen apart but if you unscrewed the bottom combustion cover bolts and levered away slightly the hot water ran fine,i replaced the fan but i would check the MI's(manufactures instructions) on how long the flue is allowed to be on yours first and has yours always had this problem,good luck

jim
February 2009