Flue exit through pitched roof

Discussion in 'Plumbing and Central Heating' started by daveinoak, 5 Feb 2007.

  1. daveinoak

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    I have just purchased a Biasi Garda Condensing Combi boiler and am trying to sort out how to flue the damned thing.

    I am able to go almost straight up and vertically out through the pitched roof (total distance about 1.5 m) however I do not like the price (£330 including the 45 deg bends I need to dog leg around a joist)

    I would like to know if it is permissable to use a horizontal flue kit and exit horizontally through the pitched roof, the total length would be 1.7m, I cannot find anything in building regs which speaks of this. (This plan would cost just £170).

    I have a corgi registered fitter, however he has only just qualified and has not come accross such an enquiry, won't commit to an answer.
     
  2. Agile

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    Its normally possible to cut and support a single joist to enable a vertical flue to go straight up. You are unlikely to have enough vertical space for a dog leg anyway.

    As long as the flue is over 25 mm from any wood then it can go between the joists horizontally. However according to the gas regulations the flue must remain accessible for inspection. A removable panel would provide that.

    Horizontal flues are usually more reliable as few people seem to be able to properly seal a vertical flue. It must tip back towards the boiler by 3° apart from the terminal length which can be horizontal or tip back.

    The prices you are quoting seem pretty high and lower prices may be possible. You could also check the prices of the equivalent Ideal Mini HE parts as they may be cheaper! Perhaps you are quoting a price with a hefty markup from your CORGI.

    I hope your rookie CORGI has approved the flue discharge point!

    Tony
     
  3. daveinoak

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    Thanks, I have decided to do some carpentry on my joist and can easily move it around the flue and retain its strength. This means I can save £35 each for two 45 elbows and £32 on a second extension kit. Using the Flue from the Ideal Mini He the total cost comes in at a rather more reasonable £150.

    Thanks for the advice.

    Dave
     
  4. scatmanjohn

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    I wouldn't be using a horizontal flue to exit a pitched roof.

    Thats what vertical flues are for.

    What do Biasi say about it.


    It will be good if it snows heavy :LOL:
     
  5. lor

    lor

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    I thought that exiting horizontally through a pitched roof was not ok but have been told it is.I cannot think why it shouldnt be safe as long as it protrudes beyond the roof.
     
  6. Agile

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    He is using a vertical flue kit ! Still paying over the odds I think !

    Its not really ideal using a horizontal flue exiting a pitched roof unless its a steep pitch angle.

    The terminal end still has to have 300 mm clearance underneath and this may mean too much is projecting horizontally. Its no worse that when the installer doesn't bother to cut off the flue and leaves it projecting 500 mm from a wall.

    Biasi ( no longer ) object to not cutting it off although most CORGI inspectors will not be very happy with it. It may not be a gas problem but just a lazy/shoddy workmanship issue.

    Tony
     
  7. lor

    lor

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    tony, I' ve installed my own condensing boiler without cutting down the flue.Not just because im lazy but so the water vapour is pushed further away from my wall and porch to prevent them getting blown back and making the wall damp.

    hope this is ok :?:
     
  8. Agile

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    Better ask your local CORGI inspector!

    Or perhaps it might be better not to bother him.

    Tony
     

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