Wood burner flue liner

[Lorn Logs]

i picked a flexi one for nownt the other day, so you think a cowl is pointless? i hope so as spending money is a pain

 

No need for all that cowl stuff as far as I can see. When it rains most, we are using the stove so the rain doesn't present a problem. When the stove's off, as it were, only the heaviest rain might run down the chimney- bear in mind the size of the chimney aperture is relatively small, and, if it's raining, you normally crack the stove on, even just for the purposes of cheerfullness, which also negates the rain issue.....

[niftysteve]

Looking at fitting a woodburner when we get the boiler replaced. Need a liner from stove to roof, are the twin wall flexi liners suitable for this? Seem like a cheaper option than rigid twin wall systems. Any advice appreciated.

 

as others have said twin wall flexi in an existing chimney will be fine , I would fit a cowel as this will seal the top of the chimneyand protect the liner, if there is enough space Chim wrap insulation can also be fitted to keep the flue system nice and hot. Also make sure you fit the liner the right way up,i recently went to fit a stove where the customers plumber had fitted the liner and it was upside down even though it had arrows printed on it

get the right adapter for the stove and fit a register plate to seal the botom of the chimney

[Stubby]

I was going to say get it the right way up but beaten to it ! It can trap more soot up the wrong way . The way it is "wound" you can seethe little ridges inside will hold soot one way u and drop t back down the correct way .

[Spruce]

as others have said twin wall flexi in an existing chimney will be fine , I would fit a cowel as this will seal the top of the chimneyand protect the liner, if there is enough space Chim wrap insulation can also be fitted to keep the flue system nice and hot. Also make sure you fit the liner the right way up,i recently went to fit a stove where the customers plumber had fitted the liner and it was upside down even though it had arrows printed on it

get the right adapter for the stove and fit a register plate to seal the botom of the chimney

 

Yes, or if you're fitting the liner in a big old flue you can just pour vermiculite insulation beads in from the top. It's relatively cheap. I think insulation is well worth the effort - the chimney sweep always comments on how clean our flue is and I always wonder why we have it swept twice a year...

 

We fitted a Brewer UFO MK11 chimney cowl from Plumbing Supplies | BES Gas & Plumbing Fittings which fixed occasional downdraught problems. In any case, I hate the sound of hail clattering down the liner.

[blades]

I would definitely use a 904/904 grade liner.... for the price difference it will last twice as long. Also, insulate it.... either use rockwool tubes around the liner or fill the void between liner and chimney with insulation like vermiculite.

If you use the rockwool tubes I would also insulate above the register plate with a couple of slabs of rockwool.

 

You don’t have to insulate but if you do

1. It will ensure you don’t get sooty goo dripping down into your stove

2. You want lose as much heat and more will go into the room

 

I hope this helps and good luck

[niftysteve]

heres a pic of the chim wrap insulation

Flexwrap chimney liner insulation - flexible insulation for flue liner uk

[Alycidon]

No need for all that cowl stuff as far as I can see. When it rains most, we are using the stove so the rain doesn't present a problem. When the stove's off, as it were, only the heaviest rain might run down the chimney- bear in mind the size of the chimney aperture is relatively small, and, if it's raining, you normally crack the stove on, even just for the purposes of cheerfullness, which also negates the rain issue.....

 

 

saw a stove the other day, not installed by us. Rusty as hell on top. No cowl, fireboard register plate. Water had run down the clay lined flue, soaked the fireboard, this had then allowed water to creep down the pipe onto the stove top. This happened over the summer. We reinstalled the stove, fitted a galvanised register plate and a cowl.

 

If you are penetrating a wall or ceiling then Building Regs stipulate that you MUST use twin wall fully insulated flue pipe such as Poujoulat TI or similar. The installation of a stove comes under Building Control, breech of the regs will leave the home owner open to prosecution if caught, dont forget the install also need a safety sign off, no sign off no house insurance.

 

A

[shooterjim]

Right peeps! We have had the back boiler removed today. In the recess is what appears to be a clay prefabricated type liner arrangement. There was a short length of flexi pipe linking the boiler to the hole inside the liner. Where the hole starts it is roughly 6" but approx 2 feet up it appears to narrow to an opening roughly 6" by 4". In the loft there was a link pipe made of Selkirk pipe. My question is, does this sound suitable for wood burner? There is a draw which plumber tested with a smoke stick, said it wasn't overly strong but enough. There is no way we will fit a liner inside this arrangement. Any info much appreciated.

[Alycidon]

Well the problem comes in sweeping it, I would try a 6 inch diameter brush up it on nylon rods as used for sweeping flexi liner and make sure you can sweep it. It is legal to use a 125mm liner on a DEFRA approved stove with a 125mm outlet, that makes an area of about 18 sq inches, 6 inch x 4 inch is bigger but if this were say 6 inch by 3 inch then I would say its a Type 2 flue and you are not allowed to put solid fuel smoke up one as there is no real way of sweeping it properly.

 

I have never seen a solid fuel chimney like this, alarm bells are ringing. I would ask whoever you have lined up to sign it off as safe to have a look at it first. It may just be a throat gather that may want knocking out or it may be a gas only flue. How does it terminate?. a raised ridge tile or a proper chimney pot?. I assume the back boiler was heated by an open fire.

 

The loft arrangement is not that unusual if a chimney stack has been removed then re instated using twin wall fully insulated pipe.

 

 

I will try and see if there is anything in Approved Document J 2010.

A

[Alycidon]

Here is a part of App Doc J that covers flue size:

 

http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_J_2010_V2.pdf

 

 

Have a look at page 30.

 

 

A

Edited December 17, 2012 by Alycidon