Central heating boiler flue distance

[Hotwire]

I have an old boiler with the old style flue which is about 1 foot square. Can anyone give me an idea what would be the shortest safe distance that a wood fence can be be placed next to the flue.

 

[45yearsagasman]

Make and model please.

 

[Hotwire]

Hi, its a Baxi WM381RS

 

[Agile]

If its a non fanned type projecting about 300mm or less from the wall then I would suggest about 1m from wall to a wood fence.

But that's primarily to allow combustion gasses to disperse better rather than any fear of fire/heat damage. 300 mm from closest part of terminal would probably be enough for that!

The original maker's tech details would probably include a distance to be left unobstructed.

Tony

 

[FiremanT]

If its a non fanned type projecting about 300mm or less from the wall then I would suggest about 1m from wall to a wood fence.

But that's primarily to allow combustion gasses to disperse better rather than any fear of fire/heat damage. 300 mm from closest part of terminal would probably be enough for that!

The original maker's tech details would probably include a distance to be left unobstructed.

Tony you should probably not give vague guesses!

OP: This is a link to balanced flue clearances:

http://support.ambirad.co.uk/article.aspx?id=10724

The manufacturers instructions over ride these, if you can find them. Your boiler, I assume, is 38,000 BTU/hr OUTPUT, you need to know the MAXIMIM INPUT (regardless of any range rated setting) - which should be on the date badge on the boiler. Then convert to Kw/hr, to use the chart properly.

EDIT: You only need the input to check clearances

 

[D_Hailsham]

Hi, its a Baxi WM381RS

This is from the Installation manual on Baxi Partsarena:

1. On a clear expanse of outside wall preferably not less than 600 mm.(2ft) from a corner, recess or projection.

2. Not less than 300 mm (1ft) vertically beneath an openable window or ventilator.

3. Not less than 600mm (2ft) from any-surface facing the terminal.

4. Not less than 300 mm (1ft) from ground level.

5. Not immediately beneath eaves or a balcony.

6. If the terminal is less than 2m (6ft) above the ground or balcony to which people have access the terminal should be protected by a guard.

7. if the outer surface of an outside wall is of combustible material it should be protected by fitting a non combustible plate so that it extends not less than 50 mm (2in) around the terminal.

 

[Hotwire]

Thanks for the replies all.

Some more info

The flue is non fanned and is 18" from the corner of the wall

The wood structure would be about 15" from the side of the flue, no part would be in front of it.

Agile

I have found the original maker's tech details but as yet I have not come across anything relating to distance to be left unobstructed.

FiremanT

The input the pointer is turned to on the boiler label is
Heat input 15.15Kw 51,700 btu/h

I looked at the link you supplied but I cant seem to see the situation I am talking about, am I missing something.

I have found the original manual that came with the boiler and it seems to be the same as D_Hailsham posted. I will give it another read and I may find something.

 

[CBF]

I would class it as an internal corner as in "H" in the above link, so therefore 600mm from the edge of the flue

 

[Hotwire]

Thanks CBF, looks like its back to the drawing board or i put a piece of metal up on the wood to deflect the heat.