Worcester 240 BF Combi flue issues...

8 Mar 2011
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United Kingdom
Hi, i've got a problem with a Worcester 240 balanced flue combi in which the emissions test was very high when tested (1100ppm). I believe the cause is a corroded inner flue duct which is letting fumes mix back in with fresh air via the air intake. When you take the flue hood off above main heat exchanger, the damaged part is the inner flue metal that starts from the boiler body and is cut about 300mm. (There is then an extension piece which is attached to the terminal which slots over this 300mm piece from boiler back) I need to know if the 300mm inner flue piece is attached to the boiler back plate and if this can be changed or is it a case of a new boiler??
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You need a RGI, flues have safety implications, or should I say danger,
Hi Mick, I am a Gas Safe registered engineer but I understand your initial concerns regarding the content of the post. I'm merely putting the scenario out there to see if anyone has come across the same problem I have to find a solution.

We don't give this kind of info on the open forum for obvious reasons. Join the CC for these questions.
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Have you checked that the part is still available?

Sometimes boilers need to be taken off the wall to sort out old flues.

With an old boiler a replacement is often easier/better/only option.


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