Twin Walled Flue & Multi Flue stove: Worth the hassel??

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  • muckybutt
    muckybutt Posts: 3,761
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    Any risk of carbon monoxide will be amply preceded by thick, visible, and unbreathable smoke

    Not correct !

    CO is colourless and tasteless and is generated when ever any fossil fuel is burnt not just wood or coal dont forget that.

    Smoke may well be able to escape but the carbon monoxide is a heavier gas, if you get a stove hot enough (as you should burn hot anyway) depending on what stove you have the smoke / fuel gasses are reburnt giving a clean burn, this still produces carbon monoxide and it will still be present even though there will be no smoke.
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  • wintergirl wrote: »
    Hi all. New to this forum, so please be gentle!
    (Apologies for the lenght of this rant - please bear with me though!)
    Many years ago in our old property we had a woodburner installed. Guys did it in a day: swept chimney, dropped a flue down, repotted the chimney and sealed it at both ends to the pot and stove. All worked lovely for the 9 years we were there.

    We then moved to a modern house with no chimney - Oh how I missed the woodburner. Lasted 4 years with darn E7 heating. Had enough by last winter, so decided to spend some of our hard earned cash getting one installed via a Hetas installer. (Hubby not very good with DIY, so needed to find a trusted installer to do it all.) First hurdle we hit was getting conflicting advice from the 3 (Hetas) installers we asked to quote. - Yes it can go where we want it; no it can't. Yes it can be straight; no it needs bends. Your wall is a stud wall and needs heat sheilding; No its plasterboard on brick and doesn't need it, etc, etc.
    After much confusion we went with a 4th installer. (A builder, but Hetas reg.) who made the most sense, and spent the longest at our property doing a thorough survey. Had a freestanding 5kw stove put in with an internal twin lined flue system.
    That was in Feb. We were pleased with the install, and all worked well, although from the very start the fire cement would fall out of the joints on the 1.4mtrs of enamel flue. Had the installers back twice; they just put more cement in, which fell out again as soon as we fired it up. By the summer we realised that they did not know how to solve the problem, so contacted another specialised stove fitter. (Hetas again)
    He came out and said he could fix the cement problem. Then asked to look at the install. Started to make comments about what had been done, indicating that it wasn't up to standard.
    I (stupidly) didn't ask him outright if he was saying it would fail Hetas / Build Regs, but thats certainly what he implied. He would get back with a quote to 'put things right'. No quote materialised, and the company are ignoring my calls / emails.

    So; we are left with an install that we are now questioning the safety of, a messy looking single flue section with cement falling out, and to cap things off, this morning after the heavy rain of last night, there's water droplets coming down the outside of the twin flue section, and dripping onto the top of the stove.

    A call to the original installers has been left to come and fix the leak. No response by them yet. Oh, and I was so angry with this guy implying the install wasn't up to scratch and then not having the courage to stand by his words that I emailed Hetas last week with the full details of what he implied was wrong, to ask their advice. They haven't bother to reply to me either!!

    Have we just had a run of bad luck with these guys? All we wanted was an install that was safe, and up to standard; that didn't leak when it rains, and that doesn't shed its fire cement when fired up. Was that too much to ask.....?

    Fire cement, once set, is brittle, and any vibration or movement in the enamel flue section is likely to cause it to break up. The flue needs to be braced very firmly against the surrounding wall(s) in order to prevent movement (stoking the fire, and riddling the grate may cause sufficient movement to disturb the fire cement)

    Last night was presumably not the first wet night since February, so something has changed. Check the exit of the flue through the wall/roof - the seal may have failed. Alternatively, if you lit the stove last night for the first time since spring, you may have melted some tar which has found its way through the failed fire cement. Water is a by-product of any form of combustion, so you may just have a condensation problem, which has again found it's way through the failed joint
  • The water was dripping from the oustide of the twin wall secion in the lounge, and was clean, so is definately coming from the roof, not internally though a part of the flue.

    Man Overboard says something must have changed for it to start leaking now, and he is right. - We had the flue swept a week or two back. The guy (NACS) used a spinning brush on what looks like an electric hand drill. Made a heck of a noise going up and down the flue.
    We have looked through the inspection plate at the boxed in section in the bedroom, and can see the bracket there holding the flue in place had come way from the wall. The wall plugs are pulled clean out. Could the vibration cause the bracket to come away, and perhaps crack any roof sealant? (The flue is Poujoulate, and has quite a tall, unsupported roof section.)
    Measuring the internal distance between the flue and the boxing in give - sides 8-9cm, front just under 5cm, back (to wall) well over 10cm. So the flue has shifted somewhat.
    Has anyone with a twin walled system have this happen to them after a sweep?
    I cannot see how the installers will be able to fix the bracket without removing at least one section of the boxing in. Can we argue that the bracket should be able to stand up to this kind of sweeping, or should the sweep of used a less 'mechanical' way to clean a twin walled system?

    Advice from any sweeps out there very welcome!
  • muckybutt
    muckybutt Posts: 3,761
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    It sounds like your sweep has used what we call a power sweep, I dont use this method but have seen it done a few times.

    It makes a hell of a din that much I do know, I wouldnt have thought that would have loosened it to that extent to be honest, but stranger things have been known.
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  • PaulF81
    PaulF81 Posts: 1,727 Forumite
    Ectophile wrote: »
    You're unlikely to die of carbon monoxide poisoning from growing your own vegetables.

    I wonder how many DIYers can actually follow Building Regs part J, and get it right?

    I did. Easy peasy. If people who can't get decent grades at school can do it and thus go into trade, most educated decent DIYers won't struggle with following the spec.

    It's not rocket science.

    Try some flexible heatproof sealant. Worked wonders on mine.

    My experience with hetas is most don't know their @rse from their elbow, tell lies when interpreting the regs to up the quote, tried to charge over 500 quid for a days work and will overcharge for materials. We had a 1500 quid quote off one for a job I DIYed for under 450. And met the regs.
  • wintergirl wrote: »
    The water was dripping from the oustide of the twin wall secion in the lounge, and was clean, so is definately coming from the roof, not internally though a part of the flue.

    Man Overboard says something must have changed for it to start leaking now, and he is right. - We had the flue swept a week or two back. The guy (NACS) used a spinning brush on what looks like an electric hand drill. Made a heck of a noise going up and down the flue.
    We have looked through the inspection plate at the boxed in section in the bedroom, and can see the bracket there holding the flue in place had come way from the wall. The wall plugs are pulled clean out. Could the vibration cause the bracket to come away, and perhaps crack any roof sealant? (The flue is Poujoulate, and has quite a tall, unsupported roof section.)
    Measuring the internal distance between the flue and the boxing in give - sides 8-9cm, front just under 5cm, back (to wall) well over 10cm. So the flue has shifted somewhat.
    Has anyone with a twin walled system have this happen to them after a sweep?
    I cannot see how the installers will be able to fix the bracket without removing at least one section of the boxing in. Can we argue that the bracket should be able to stand up to this kind of sweeping, or should the sweep of used a less 'mechanical' way to clean a twin walled system?

    Advice from any sweeps out there very welcome!

    I would not be at all surprised if the vibrations from the power sweeping system were sufficient to pull the plugs from the wall.

    Did you get a certificate from your NACS sweep? It is possible that you may be facing an insurance claim, which may be hotly debated between your installers, your chimney sweep, NACS, and your own home insurers!

    I just re-read your original post, and you mention the fire cement 'falling out' of the joints. This should not be possible, unless the joints are upside down
  • Power sweeping generally puts a lot less stress on a flue than conventional brushes, and it's most likely what I'd have used on the flue in question. I'd say that if it's managed to pull plugs from a wall, that they were never fixed properly in the first place or were the wrong sort of fixings.
  • hethmar
    hethmar Posts: 10,678
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    Read your warranty details, I think you may find that mechanical sweeping is a no - no.

    The fire cement is probably cracking round the stove pipe? You can, as already mentioned get a high temp product.

    I take it you have a 7 year carbon monoxide monitor? Also if you dont have a temperature gauge on the stove, buy one and run it according to the temps given in your stove manual. If you run it too high for long periods you could damage the installation/stove - if you run it too low you could get a build up of resin/debris.
  • muckybutt
    muckybutt Posts: 3,761
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    hethmar wrote: »
    If you run it too high for long periods you could damage the installation/stove - if you run it too low you could get a build up of resin/debris.

    ^^ DITTO ^^

    I went to a two year old Clearview stove yesterday to sweep and service it..... the baffle was completely !!!!!!ed for starters, looked more like it had been in for years, the metal on it had delaminated and was severly buckled.
    Onto the sweep - after three meters it didnt feel or sound right so down came the brush and out came the torch and mirror, I was greeted with the sight that the liner had completely gone, it was visable upto about the three meter mark after that there was nothing but fresh air, there was also a large tear in the liner about 1.5m up from the top of the stove.

    The liner...or lack of it combined with the baffle led to the conclusion that they had over fired the stove leading to very premature failure of the installation.

    When questioned the customer said they only burnt softwood and always had it blazing - overfiring !

    Expensive lesson learnt.
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  • Even a stopped clock tells the right time twice a day, and for once I'm inclined to believe Withnail is right. We are indeed drifting into the arena of the unwell.
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