Location of gas boiler flue

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We intend to build a lean-to conservatory at the rear of our semi-detached house. The neighbour's house has a small extension already so our conservatory will be alongside it. There will be a gap of about 600mm between the two structures. Now currently the flue from our gas combi boiler is about 200mm below the level of the (flat) roof neighbour's extension and about 300mm on our side, but when we build the conservatory this flue will effectively be sandwiched between the two structures. Is this a potential problem?
 
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Side view proposed conservatory location.jpg

Sorry should have included this in my post. The flue pipe can be seen near the top centre of the photo.
 
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If you are not building over your flue then, depending on the boiler model, you MIGHT be able to get a plume management kit which a gas engineer can fit to let it discharge above the two flat roof levels.

Tony
 
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Read the manual for flue clearances. I would say it can't be done.
If you are not building over your flue then, depending on the boiler model, you MIGHT be able to get a plume management kit which a gas engineer can fit to let it discharge above the two flat roof levels.

Tony

Dan - thanks for the advice. The installation is at my son's house so I will ask him to check the manual.

Tony/Agile - thanks for your input. As I said to Dan above, the installation is at my son's house. I know he has a Vaillant combi boiler but I couldn't tell you what the model number is.
 
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Most condensing Vaillants have a plume management option.

None of the non condensing ones do!

Tony
 
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Most condensing Vaillants have a plume management option.

None of the non condensing ones do!

Tony

It's a Vaillant ecoPlus 837. According to the on-line manual for this boiler the flue must be at least 200 mm from an internal or external corner. So if we ensure that the edge of the new conservatory is at least 200 mm from the flue then I think we are ok, as it is more than 200 mm from the other internal corner (where the neighbour's extension starts).
 
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Having just looked in the same manual, I would be surprised if your scenario were exactly what they had in mind when they wrote that rule!
 
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No it is not!

But there should be a plume management system which could extend the flue to discharge about 900 mm higher up!

Should be fitted by a gas reg though!

Tony
 
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No it is not!

But there should be a plume management system which could extend the flue to discharge about 900 mm higher up!

Should be fitted by a gas reg though!

Tony

No problem - will do, IF NECESSARY! Will check with Vaillant in the morning.
 
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Please let us know what they say.

OK. Have checked with Vaillant. Yes, this is an unusual situation which is not covered by the list of different scenarios in their technical manual! The great unknown is whether there would be sufficient air flow into the boiler (and exhaust flow from the boiler) with our scenario of having two internal corners in such a narrow "corridor". The technical guy at Vaillant recommended either extending the flue horizontally right out to the front edge of the conservatory or alternatively using a 90 degree bend and going up vertically.

I would prefer the latter because extending the flue horizontally to the front of the conservatory would mean the exhaust would then be within 300 mm of an opening window. We can go a metre or so up the main house wall with no problem, although the pipe could be cut down to whatever size we like it seems, as long as it is above the conservatory roof level. I think I would prefer a shorter length because I can foresee the plume being an issue with the neighbour if it starts drifting across their bedroom window above.

So there we have it!
 
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Oh dear!

I don't know why Vaillant technical are talking to you because you don't understand anything about flues and have totally mis-understood what they were hopefully trying to tell you.

You are not permitted to use flue components OUTSIDE apart from the plume management system.

I do hope they were not actually suggesting this.

There will be plenty of air flow into the boiler! The danger is that this will recycle products of combustion back into the boiler. But you will not realise why this is so dangerous.



Tony


NOTE to Vaillant Tech, please check that anyone you give gas advice to has a valid Gas Safe number!
 

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