multi fuel stove existing ceramic flue or flue liner help

8 Jun 2011
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United Kingdom
I have a chimney on external wall of my lounge. The chimney sits external to the house so there is no breast in the room.
It had a gas fire in previously and has an 8" clay/ceramic liner in the chimney going straight up.
I'm building a fake chimney breast out of block in the lounge to house a multi fuel 8kw Stovax stove.

Due to measurements and restrictions its going to be tricky to put a flue liner down and have soot access.

I was going to put a 904/316 flue liner down and then a T piece with cap on the bottom going to the stove rear flue exit. Problem is the stove sits further than 6" away from the T horizontally.

Options are:

45 out of stove rear flue, stove pipe to 45 T piece with cap onto 6" flue liner inside the ceramic liner. Soot door on the rear of chimney giving access to T piece Cap for soot collection.


45 out of stove rear flue, stove pipe and break into the existing flue ceramic flue. Then fill the void below leaving a drop gap in the chimney for soot collection and have a soot door at the rear of the chimney outside.

Its easier/cheaper to go with the latter, but does anyone see any issues?
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Why dont you fit a sump adaptor and sweep through the stove?
I'm not sure what a sump adaptor is. I'm happy to sweep through the stove though, but wanted more to hear advice on whether an external chimney with a ceramic liner would be ok for the flue of the stove, or if people had seen problems and advised putting a steel liner down.

As this comes up so often, I’ve put together this generic post; read the links but not all may apply to you.

You can DIY but you need to understand the Building Regs (which changed in October), submit a Building Notice & pay a fee. Your LABC will inspect &, assuming everything is OK, issue a compliance certificate; the BI may want to witness smoke & spillage tests. No compliance certificate may lead to difficulties when you come to sell your property; if cannot produce a compliance certificate in the event of a problem, your insurance company may invalidate your policy & reject any claim.

Lots of archive threads on this, & other things you have to watch out for, here a few links for you to read: leaflet.pdf

& some more sobering just in case you think it’s all a load of old tosh:

Also get at least 3 quotes from local independent HETAS installers:

You might be pleasantly surprised & you should ask yourself if you really want all the hassle & risk getting it wrong; climbing onto the roof with an 8M stainless steel snake on your back is not for the feint hearted!


Read more: //
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Thanks for that i'll have a good read through.

I've had a couple of HETAS people around and due to my arrangement its not a clear "do it this way". I've even seen the HETAS installation guide and they dont have an example for my setup.

The guy recommended doing what i suggested in going stove->45->pipe->Into clay liner
and then build up underneath leaving a void for soot collection with a soot door in rear of chimney outside.

Problem is i need to tell my builder what to do with the chimney before i get a stove fitter in.

So really i just wanted to know if i should go down the liner route or flueing into external chimney ceramic liner is sufficient.

Thanks indeed
If you have a clay pot lined chimney then you dont need a liner, fit a sump adaptor to that and then your vitreous to that
The problem with using an 8” open fire clay liner with a log burner or multi-fuel stove is it’s rather too large to maintain all important flue temperature through to the pot. Most HETAS installers (& I’m not one) will recommend either a 5 inch or 6 inch max twin wall SS liner, insulated full height with loose Vermiculite; but don’t take my word, check it out. ;)

Incidentally, my own personal stove is an 8Kw Stovax Riva inset; coming up for its 3rd year, a great stove & cheap to run. :LOL:
Thanks again guys.

So It may be best to go for the liner in the end as you say the 8" clay may not draw correctly?

I can't go sump on the bottom of the clay liner as my stove flue will be slightly above the bottom of the clay liner. I guess i could smash a bit off, but would be unsure of seals then.

Only thing i heard about the twin liners is they need replacing every 10 years. We're looking at this house to stay longer than that.

If i go liner it may make the chimney build a bit easier.
I'd go Stove->45 bend->flue pipe->45 T piece with Cap->6" Liner 904/316SS up chimney->suspending cowl.

hmm decisions

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