Flue Liner - Wood Burning Stove

[whoami]

I'm in the process of getting quotes for a wood burning stove.

It'll be installed where there is currently a traditional open fire.

2 of the installers are adamant that I need a stainless steel liner installed as part of the job. The 3rd guy is equally insistent that there is a perfectly adequate clay liner already in place and that a steel liner is not required.

Clearly, I want to avoid spending money unnecessarily. However, I obviously want to make sure that the job is carried out properly and safely.

All three potential installers are HETAS registered.

Any input gratefully appreciated.

[Simpo Two]

My input is that I have a 5Kw stove connected directly to a chimney lined with clay pots (ie round tubes, house built 1988) and it works perfectly. No doubt liners are required in some chimneys but in others I think it's unthinking or profit-making hokum.

Like you, I had similar conflicts with plumbers when my boiler was kettling.

[Little Lofty]

As far as I'm aware you don't have to have a liner if the existing flue is in good condition. Ring Hetas technical they are pretty helpfull.

[whoami]

I tend to agree that their insistence that I need a steel liner is a nice little earner for the fitter.

One of the 2 also stated that I needed a 904 grade liner (roughly double the cost of standard 316 stuff) but couldn't explain why this was the case.

I'll call HETAS tomorrow. Unless they point out something obvious, I think I'll go ahead without a replacement.

[bigdom]

You don't 'need' a liner, although depending on size and volume of chimney lining it could certainly help.

My chimney is lined with the better of the 2 liners, in effect, longer life I think 25yrs. When it's swept, the sweep is amazed at how clean it stays. Ours is used daily for 6 months a year - when the missus starts to feel chilly..

My mates house, older 30's build with a capped off fire place in the 2 bedrooms above the lounge wasn't lined, onky used a handful of times in the 2 years since installation as it simply won't draw due to chimney volume. Log burners only send 15-20% heat up opposed to open fire at 70-80%.

[Simpo Two]

whoami said:

One of the 2 also stated that I needed a 904 grade liner (roughly double the cost of standard 316 stuff) but couldn't explain why this was the case.

904 is a higher grade stainless steel so will last longer. How come a HETAS certified expert doesn't know that, and I do?

As Bigdom says a flue can have a useful effect on the draw of the fire - for example a large, cold chimney will have a downdraught that can make the fire difficult to light and blow smoke into the room, at least on start-up. But if you live in an average house I can't see this would be a major issue.


By the way, flues eventually corrode through and have to be replaced... just like that other great invention, the combi boiler.

Edited by Simpo Two on Thursday 22 January 11:15

[Carl_Spackler]

Simpo Two said:

My input is that I have a 5Kw stove connected directly to a chimney lined with clay pots (ie round tubes, house built 1988) and it works perfectly. No doubt liners are required in some chimneys but in others I think it's unthinking or profit-making hokum.

Like you, I had similar conflicts with plumbers when my boiler was kettling.

My input is almost exactly this also, we went with no liner route and 2 years down the (no) line(er) don't regret it.

[softtop]

Just on the same journey.

My thoughts are that if only 20% of the heat is going up the chimney then all smoke is never hot enough to race out the chimney, more of a saunter with time to deposit tar on the sides of the chimney. This could cause a future chimney fire. Maybe not when the log burner is in, maybe if it is removed and another standard fire is fitted. Happy to be challenged on this thought, if you hurry you will save me the price of a liner.

[Gaspode]

AIUI you only need a stainless liner if you don't have a ceramic liner - if the smoke gets to the mortar you can be in trouble, especially if you don't run the log burner at the right temp.

The different grades of stainless give different service lives, ISTR it's 10 years for a cheap liner or 20 years for an expensive one.

Our neighbour has ceramic liners and has no problem, we went for stainless as we couldn't afford to have ceramic liners installed.

[guindilias]

Have a smoke test carried out by a sweep, he'll be able to tell you whether the flue is suitable for use without a liner.

[Simpo Two]

softtop said:

Just on the same journey.

My thoughts are that if only 20% of the heat is going up the chimney then all smoke is never hot enough to race out the chimney, more of a saunter with time to deposit tar on the sides of the chimney. This could cause a future chimney fire. Maybe not when the log burner is in, maybe if it is removed and another standard fire is fitted. Happy to be challenged on this thought, if you hurry you will save me the price of a liner.

I seem to recall that the amount of tar and other goo produced depends on how hot you run the stove - hotter = less IIRC, and that most of it is supposed to run back down into the fire and be re-cooked. And also, if the chimney is not very hot, how is it going to catch fire...?

For peace of mind you can always get a sweep in with a CCTV camera - then you know exactly what's going on.

[BFG TERRANO]

I fitted a liner. Good quality twin wall stainless job with 20 year guarantee. Fluesupplies.com. I was told it makes it more efficient, easier to clean and reduces chimney fire risk. Dunno if true but 3 winters of many fires we've had no problems.

[Podie]

We fitted a liner - it came with the stove! http://www.stovefittersmanual.co.uk/

[crankedup]

If/when you come to move on any buyer with half ounce is going to ask 'has a liner been fitted'? If it's a no the buyer is likely to wonder what else has been short cut and how much will it cost to have one installed. Just something else to consider.

[minivanman]

I fitted a liner to mine, its so cheap its not worth not doing it. Took 20 minutes to fit. However if you've already got a clay liner I'd tell them to jog on, there's no good reason to swap it for the sake of it. I'd even say clay might even be better as you won't have the corrosion issue?

[Simpo Two]

crankedup said:

If/when you come to move on any buyer with half ounce is going to ask 'has a liner been fitted'?

Wouldn't they be more likely to say 'Has that got a HETAS certificate/building regs thing?'


ATEOTD apart from the the known issues, they are only metal boxes and tubes, not nuclear reactors.

[dickymint]

Podie said:

We fitted a liner - it came with the stove! http://www.stovefittersmanual.co.uk/

And if you catch Justin on a good day his price is open for discussion - I did he was on a roof when I nailed down the price

[Podie]

dickymint said:

Podie said:

We fitted a liner - it came with the stove! http://www.stovefittersmanual.co.uk/

And if you catch Justin on a good day his price is open for discussion - I did he was on a roof when I nailed down the price

I thought his name was Julian...

[whoami]

Well, a lot more input and opinion that I expected.

Thanks to all who contributed.

[Autopilot]

minivanman said:

I fitted a liner to mine, its so cheap its not worth not doing it. Took 20 minutes to fit. However if you've already got a clay liner I'd tell them to jog on, there's no good reason to swap it for the sake of it. I'd even say clay might even be better as you won't have the corrosion issue?

When I had my chimney swept, we found that we didn't have a liner fitted. Not the end of the world, but the chap gave us his mates business card and said the job required to fit one would involve scaffolding and all sorts.

How did you fit yours in 20 mins? I assume you just got on the roof, fed the liner down, clamp either end down, job done! I figured that including stopping for tea, this was about 2 hours work at the most (every job I do takes me twice as long as there's always a tool I haven't got so involves going out and buying one!)

I went on Fluesupplies.com and saw the fitting kit for about £65 and the liner would be about £200, yet all people I have ever spoken to who've had one fitted all seem to say it's over a grand to do!!