Combi flue.

21 Apr 2005
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United Kingdom
I have a question regarding the flue on a Combi boiler.

I recently moved and my new house has a kitchen extension on the back. Next door has a similar extension, albeit their's is about 3ft longer than ours. Although separate extensions, they are only inches apart.

This in itself is not a problem, however, next door have replaced their boiler with a combi and the flue now exits out of the side of their extention wall, consequently, it is only about a foot away from one of our(opening) kitchen windows.

I have raised the issue because obviously I am concerned about fumes when my window is open. They maintain they only have to fit the flue a set distance away from their own windows, which I find hard to believe and indeed think they are making excuses.

Surely they can't give us their fumes? I suspect there must be a minimum regulatory distance, but would like to be armed with this info before I have another go at them.

Is there a minimum distance allowed between the end of the flue and any opening window and what is it?

Many thanks.
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they have to fit them away for other peoples to

sheesh nice nieghbours, call CORGI and see if they will send an inspector to have a butchers at it
Manufacturers state that a fanned flue should be at least 2.5m away from an opening (door or window) in a building directly opposite. BS 5440-1.
Tell them that one! Their installer should have known that.
Nice people U live next door to. Call local council building control, they seem to have more power than the toothless dog.
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3 weeks to come out to look at it, then 2 weeks to send the letter, then a further 2 weeks that the installer has to move the flue. Don`t hold your breath......At least your kitchen window won`t frost up! :D
I still think Mr Corgi Inspector will want to have a look and will want to know who the installer is. You could call Building Control and Corgi but to save a possible 'War' try and have a friendly chat with your neighbour first and tell them the regulations.

Approved Document J (April 2002) outlines the Minimum separation distances for terminals (Flues). It states that:

The minimum seperation distance from a surface or a boundary is 600mm facing the terminal. (Smaller separations to the boundary may be acceptable for appliances that have been shown to operate safely with such separations from surfaces adjacent to or opposite the flue outlet).

I'm not sure if this terminal actually 'faces' your wall/window so this seperation may not apply. However, the separtion between a terminal and an 'opening' (of which your window counts as) either horizontal to the opening, above or below it, is also outlined. The separation distance is dependant on the 'Appliance rated heat input which is given in kW net and is outlined as follows:

Below an Opening:
0 – 7kW Heat Input - seperation required is 300mm.
>7kW - 14kW - seperation required is 600mm.
>14kW to 32kW - seperation required is 1500mm.
>32kW - seperation required is 2000mm

Above an opening:
0 – 32kW - seperation required is 300mm.
> 32kW - seperation required is 600mm.

Horizontally to an opening:
0 – 7kW - seperation required is 300mm
>7 – 14kW - seperation required is 400mm
>14kW - seperation required is 600mm.

Hope that helps. I can email you a copy of Approved Document J if you require it.
Rather than falling out or getting heavy handed with the neighbours I will discretely use Blasphemous's figures and have a chat with them.

If they have little choice on boiler position, it may be that fitting a new window frame in my house, with the opening on one side, may meet the requirements. As long as they are prepared to pay for this, I will try to be helpful (even though they weren't ;) )

Can't stand neighbour problems and ended up moving once due to it.

Many thanks for all your comments.
Thats not really very relevant.

Assuming its a condensing boiler, which it should be, then the Building Control guidelines ( but not yet statute ) is the flue should discharge over 2.5 m of your OWN land before the boundary.

Regardless of any dimensions no flue should be fitted where it causes danger or inconvenience to others.

You can complain to your Environment Health Officer and/or to CORGI.

Since its unlikely to be a CORGI installer I would prefer you to complain to CORGI but the enforcement can only be undertaken by the EHO. If it were ( unlikely ) a CORGI installer then CORGi can serve a defects notice.

You could also complain to Building Control although they have no duty towards you only that Building Regulations are complied with.

Agile said:
Regardless of any dimensions no flue should be fitted where it causes danger or inconvenience to others.

You can complain to your Environment Health Officer and/or to CORGI.

I take your point Tony. Thanks mate.
There are some recommendations in the Manufacturers instructions for each boiler.
I had a look at the first set of instructions I came across which happened to be for a Baxi 130 HE and they said
J From a surface facing a terminal. 600
Apart from the 2.5m /1.5m from the boundary depending on the height issue with the building regs, there is a legal issue of tort if any harm comes to you or your property through your neighbours actions.
CheekyR....Without getting into the distance requirements. Don`t worry to much as the Fumes and steam you see coming from the flue are only water vapor and CO2 . More of an inconvience than dangerous. But play the dangerous card with neighbour to get them to move flue
if you really dont want to rock the boat and if its a new condenser you could try and find out if its got a pluming kit available for it. that should raise the flue exit away from your window and keep them happy and allow your window to be open in most conditions.

personally i would tell them to move it regardless of future neighbour problems. it is after all exiting onto your property....wonder how much they would like it?. tell them you intend to extend past the flue so it will need to be moved :LOL:
You may not want to cause a fuss, but one day you may wish to sell your property, and buyers may well be put off if they spot the flue being a nuisance, or knock you down on price.

Its in your interest to be as diplomatic as possible, and to do your research properly. I'd certainly speak to Corgi for advice, even though they can't act for you, and yes your EHO or building control, who will define and enforce planning and or/nuisance law.

In terms of what you say 'over the fence' I'd just briefly outline your concerns, and that you will write to them formally to put them completely in the picture. Its unfortunate, but you feel that you havn't been given any choice.


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