Replacing a boxed in flue


5 Aug 2008
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United Kingdom
My Glow Worm system boiler is end of life. The boiler is in the kitchen and has a 5.2m standard horizontal flue through the wall. The flue is boxed in using batten and plasterboard. Appropriate inspection hatches are present.

As most flues are a standard size, can an installer pull the existing flue through the boxing? The flue is on the ground floor so I would have thought that you could pull each length through using a piece of rope and then push it together within the boxing.

If not, what is standard? Do you expect it to be removed before you arrive?

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I'm afraid the boxing will have to come down. Depending on boiler most newer flues need securing screws at joints. Also flue needs to be supported along the route so if flue clamps were fitted to old flue they will need to be slackened off to remove the older flue.
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Reactions: bsr
A lot of condensing boiler require the flue to fall back to the boiler ,depending on the make it’s 25 mm per meter.,clipped and screwed at ever joint
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Interesting here's the current situation. 6m of flue only fixed to the boiler at one end and the core through the wall at the other!

Not good practice I guess? But ok for 20 years.

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