Ambiguity over boiler flue pipe distance from a boundary

[nadimaj]

I am looking at several diagrams but it's not clear to me what the regulation says about the distance a flue pipe from a neighbours boundary. I've seen 300 and 600mm.

II would like to route our pipe from our side passage, coming out from a wall in the utility room, with an elbow joint and protruding upwards through the roof covering the side passage. The passage is around 750mm wide. The neighbours side is a flat roof garage which is 2m wide, and then comes his garden, and his house about 25m away. He will not be affected by any exhaust gases and neither will he ever get permission to build anything in the spot that is his garage.

If I place the flue 300mm from my wall, I have 450mm free from his side. The prevailing wind here suggests the gases will never carry to him but get smacked against my wall. He was originally OK with the distance but has asked me to extend the pipe 1m on top of the side passage roof. My plumber says this is a bad idea. It certainly feels like it.

Any thoughts or suggestions? The alternative is to extend the flue about 10m down the side passage and into the garden.

Thanks

 

[RandomGrinch]

I'm afraid, I believe this is only something your RGI will be able to design with you on-site.
It will depend on many factors such as the availability of flue kits and the Manufacturers Instructions of your current boiler.

 

[Deleted member 267285]

Photos would be a good help. Also what make and model of the boiler? It’s the manufacture that usually specifies the boundary as well as building regulations, some of which are often the same.

 

[nadimaj]

Thanks. Boiler is a Vaillant 637 ecotec plus System.

The side passage roof in question:

View looking from garden at our house. The garage represents the boundary, and a fence in line with this carries on.

Plan view:

 

[Deleted member 267285]

I would get it so that the flue terminal is horizontal to the boundary, not pointing at it, and keep it to 300mm or greater. See attachment.

 

[DP]

300 from your wall and 600 from the boundary for Ideal boilers.

https://idealheating.com/uploads/documents/flueing-and-accessories-guide-logic.pdf

As has been said before, let the RGI decide as MI rule for GSIU.

Might be better to let the flue discharge through the kitchen into your garden

 

[nadimaj]

Thanks. Could you please expand on those acronyms? And it's too late. Kitchen is all done. Builder let me down with late planning and design of plumbing solution.

 

[Madrab]

RGI - Registered Gas Installer - he has to make the correct decisions as it's him who is untimately responsible
MI - Manufacturers Instructions - these are the final word as far as installation for a specirfic appliance is concerned
GSIU - Gas Safety (installation and Use) regs - in the abscence of the MI's or any relative info that the MI doesn't cover, then the regs are the bible.

What you propose is quite a unique situation and could be a bit of a grey area and that's when the rules and regs can become difficult to apply.

​

 

[nadimaj]

Thanks. Yes, every builder, plumber and "expert" has an opinion. Makes the whole thing so much more exciting! My RGI has said words to the effect of:

"mmmmm, errr, it should be OK. The regs are not clear."

And I've asked others. All provide answers that don't clarify anything.

 

[nadimaj]

I may have been confused by the terminology. Below is the clearance diagram from Vaillant. When they say "vertical flue clearance" in the below diagram/chart, they mean the horizontal clearance of a vertical flue! Looking at it with fresh pair of eyes (we get wiser by the minute), I think I'm OK with 300mm from the boundary? On a scale of 1-5, with 1 being STRONGLY AGREE and 5 being STRONGLY DISAGREE, what would you say?

 

[denso13]

Yes, 300mm to boundary and house wall will be ok.

 

[polesapart]

Observe distances "G" and "E" and, if relevant, "Z".

On the basis of info supplied you're good to go.

 

[muggles]

You need 300mm to the boundary (distance E) and it needs to be 500mm from the wall of your house (distance H). Given that your passage is only 750mm wide, this cannot be achieved.

Is this a proposed or an existing installation? A 637 is likely to be massively oversized for your house, unless it's a lot bigger than it looks.

 

[nadimaj]

It's bigger (6 bed). Proposed. What's 50mm between friends? I'm going ahead, if there's trouble will just have to route it 7m down to the garden.

 

[muggles]

Even so, a 637 should run 35-40 radiators. Has the installer carried out a full room by room heat loss survey as required by Building Regulations prior to specifying this boiler? Oversized boilers cost more to run and have a shorter life expectancy.

Anyway, back to the issue at hand. 300mm+500mm+110mm flue diameter is 910mm width required in order to comply with the installation instructions.