Do I really need a new condensing boiler flue?

14 Jan 2008
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United Kingdom
Presently have a conventional Trianco 28/32 Redfyre oil boiler with 5" non balanced flue, which is surrounded by a stainless steel outer wall. It runs approx 2m vertical from boiler into loft space then 45deg elbow then 2m at an angle then 45deg elbow, then finally 1.5m vertical out through the roof into the open air.

I'm told new boilers are condensing type.
Do I really need to change the old flue, it alooks in good working order? If so why?
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They flue is a part of the boiler and as such designed for each make and model individually.
Would you put diesel in a petrol car because your last car was diesel? :rolleyes:
But to be more precise.

Your flue was specified for a boiler which emits high temperature gases and generally runs dry.

A condensing boiler runs lower temperature gases and has to put up with severe internal condensation which contains acid, encouraging corrosion.

The latter flue therefore has to be made of a corrosion resistant material, such as plastic, stainless or aluminium, and incorporate water resistant downward facing seals at all joints.

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