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A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. Historically the term flue meant the chimney itself. In the United States, they are also known as vents for boilers and as breeching for water heaters and modern furnaces. They usually operate by buoyancy, also known as the stack effect, or the combustion products may be 'induced' via a blower. As combustion products contain carbon monoxide and other dangerous compounds, proper 'draft', and admission of replacement air is imperative. Building codes, and other standards, regulate their materials, design, and installation.

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  1. S

    Flue position - will this be a problem?

    We are considering buying a house which currently has a 20 year old Ideal Icos boiler, so we're factoring in replacing the boiler soon. Current boiler is on an external kitchen wall with the flue going straight out. However, it's positioned in between a door and the kitchen window, quite close...
  2. G

    What type of flue liner do I need?

    Hi Guys, My chimney failed the test so I need to install a flue liner for my Gazco Stockton gas fire. It was over a year ago when the engineer condemned the chimney and I remember him also saying something about it needing some sort of box fitted into the fire recess but I can't remember the...
  3. Stout0607

    Flue integrity failed I'd or at risk

    flue integrity test failed on a room sealed boiler however not effecting combustion and not leaking into room, would it still be I'd or can it be at risk.
  4. OldSoul71

    Remove Old Unused Flue Pipe?

    Hi, long story short, our boiler has been replaced with a combi and the loft and airing cupboard are now devoid of tanks and pipework, except.... ... this old flue pipe, which was once connected to the original boiler when our home was built in the mid-80s. It runs from a vent on the roofline...
  5. J

    Wanted vaillant ecomax 18e flue collector cardboard template

    Hi can anyone help. Flue collector on vaillant ecomax 18e needs refitting but no longer have the cardboard template included in the kit. Does anyone have one? Full kit is 076560.
  6. dilligaf

    Glow Worm Micron 30FF Flue?

    The flue for a glow worm micron 30ff is apparently obsolete but there must be other flues that would fit it surely, it's just a standard 100mm horizontal flue right? I mean when a bg gas engineer tells you that you'll have to change the whole boiler as well because you can apparently no longer...
  7. S

    Mixing Vertical and Horizontal Combi Flue

    My installation has been classed as Dangerous 'Do not use' by my boiler manufacturer. I have an Ideal Logic 30kw Combi boiler mounted as high as can be on the kitchen wall. Flue exits out through the wall via an elbow but emerges above a flat roof. Unfortunately it's somewhat less than the...
  8. M

    Sealant for external flue run.

    Hi all. Got to run a Vailliant flue externally and been told by vailliant I need a heat resistant flexible silicone. Can anyone recommend which silicone to go for? Cheers
  9. E

    Back boiler venting and flue requirements

    Hi all, Apologies if this has been covered elsewhere but I can't find an answer to my questions. I have a back boiler and gas fire which h has been serviced regularly over the years by different engineers with no issues. Last time , the guy wanted to condem it due to not being compliant with...
  10. G

    Thoughts on this flue

    Installed 2 days ago, Worcester 4000. Haven’t seen anything like this before, any thoughts. Personally I would have gone horizontal with an offset bend in the roof space ( to get minimum distance from boundary) and terminated at the gable end.
  11. H

    Can the flue be bent upwards to meet the distance rule from a window?

    I had a combi boiler put in my rental property about 10 years ago by a contractor arranged by the letting agency and I assume qualified. Gas safety checks have never highlighted a problem. This year they have turned off the boiler because the bottom of the flue pipe is 200mm from the opening...
  12. M

    Vertical flue/ roofing query??

    Hi guys. How many of you use a roofer to help with vertical flue installations, or do you rather do it yourself?? I’m not one for heights so would rather not if possible.
  13. T

    Kitchen extractor ducting to boiler to boiler flue.

    Morning, Im in a top floor tenement flat with access to the attic space. I have a combi boiler with flue that emits vertically up through the roof. My kitchen is situated internally with no easy access to an external wall. Could I fit a kitchen extractor that ducts vertically then right angles...
  14. T

    Worcester 34cdi noise coming from resonator intake and flue smell

    Hi, I have a Worcester 34cdi boiler and it has started making a droning noise when it comes up to temperature or cycles. The sequence appears to be: -Fan speeds up (purging?) -Sparks, then lights (flame icon showing on display) -Fan slows down -Droning noise (like Jaws is coming, Daa-Daa...
  15. C

    Best lubricant for new seals on a Gazco balanced flue?

    Hi. Reinstalling a Gazco balanced flue and wondering what an ideal (silicone?) lubricant would be.
  16. G

    Rear entry flue water heater

    Morning all I’m Trying to find the best 30kw water heater to replace an old main medway. Must be rear exit flue. Any ideas please?
  17. E

    Smell of 'toasted sesame oil' from boiler flue vents. (block of flats)

    I live on the 3rd floor of a 6-story block of flats. (26 flats in total). During the evening when all people are inside their flats and using their boilers to heat their flats, there is obviously lots of steam coming out of all the different Boiler Flue Vents. if I open my window or go outside...
  18. M

    Help with leaking boiler flue?

    Hi, I've been having trouble with my boiler leaking for months. We thought we'd fixed it last winter as haven't had any trouble throughout the summer but in the last week or 2 it's leaked again, we had several people out to look at it but no one fixed it. Tonight we've had someone else look and...
  19. T


    does anyone know if the ideal logic flue sampler cap should have an "O" ring in it please.
  20. G

    Should a Soffit flue extension kit be fitted ?

    Having purchased a new build, the current boiler flue terminates flush at the wall, the vented spent fumes from the boiler flue is within 300mm of the end of the vented soffit, a strip of UPVC is covering at least 400mm of the vented soffit, should an extension soffit kit be fitted to prevent...
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