Permitted boiler location question

[MattyD]

I'm planning an extension, and I eventually want to move the boiler into a small utility room. The boiler would be a new, wall hung model, not a combi.

The question I have is: are there any specific rules about the location of a boiler which mean that it has to be on an external wall, or could it be on an internal wall with a flue up through the roof? I assume that ventilation needs etc will apply wherever it is. It will be single storey extension, with a flat roof.

Obviously I'll get the work done by a qualified engineer, but at the moment I want to work out where I could put cupboards, washing machines etc.

Thanks in advance for your advice

Matt

 

[jdey]

Here's the official guide which every CORGI engineer is supposed to use to assess the most suitable location for your condensing boiler. It may be the case that there isn't a suitable location in which case you are able to install a non-condensing boiler if you want to.

http://www.odpm.gov.uk/pub/731/Guid...tProcedureforDwellingsPDF1258Kb_id1130731.pdf

You can also find a copy of the Building Regulations Part L (doesn't actually say much) & the associated Approved Document (which supplies the actual details) http://www.odpm.gov.uk/pub/730/Appr...rindwellingsAmended2005PDF978Kb_id1130730.pdf
on the same site.

 

[jdey]

You'll also need to read Appendix J http://www.odpm.gov.uk/pub/661/ApproveddocumentJPDF396Kb_id1130661.pdf

which covers the siting of flues. Essentially, a condensing boiler flue needs to be located so that a natural draught will disperse the plume. In a terraced house situation like mine this means the flue would have to exceed the roof of the house. Making it both ugly and inpracticable. Hence my exemption.

 

[ChrisR]

Again, jdey misses the point cos he's bound up in his own neurosis.

You can certainly take a boiler flue up and out of a flat roof. It doesn't have to be on an external wall. Though there is common ground, all the boiler manufacturers have their own rules about where flues can go. On top of that it mustn't be a nuisance to a neighbour. If you look at the installation manuals for a few boilers you'll soon get the idea. Don't bother about non-condensng boilers; its unlikely you could legally fit one, even if you wanted to.

There are many manuals at partsarena.com/baxi (look at the HE ones which are the condensers, eg Suprima HE, Baxi Platinum..) or any of the others eg Vaillant, Worcester, Keston (notably) etc

 

[croydoncorgi]

The key point to remember about flue siting is that the only difference between the 'plume' from a conventional gas boiler and that from a condenser, is that the condensation makes the plume visible! Condensate steam (or more accurately, water vapour) is completely harmless give or take a slight touch of acidity. Any other combustion products are exactly the same as for a non-condensing boiler - actually worse, because non-condensing combustion temperatures are higher, producing more NOx gases, and also condensation has some washing effect on the flue-gas.

As has been stated - boiler manufacturers specify siting limits for their own products. You just need to stick to these and not directly affect the neighbours or members of the general public using public roads, etc..

 

[chrishutt]

a condensing boiler flue needs to be located so that a natural draught will disperse the plume. In a terraced house situation like mine this means the flue would have to exceed the roof of the house.

You've got yourself in a muddle, confusing different sets of rules for different situations. You really need some professional advice.

 

[croydoncorgi]

And here's one ESPECIALLY for our ODPM-fancier:

from 'Guide to the Condensing Boiler Installation Assessment Procedure
for Dwellings', apparently your favourite bedtime reading:

Where a plume diverter terminal is used, the distance should be measured in the direction of flue products.

What this means is that if you put a plume-management kit (as available for several condensing boilers) on the end of the flue, to divert the plume up and away from the house, distances such as the 2.5m specified minimum may no longer apply....

 

[croydoncorgi]

duplicate

 

[Slugbabydotcom]

Here's the official guide which every CORGI engineer is supposed to use to assess the most suitable location for your condensing boiler. It may be the case that there isn't a suitable location in which case you are able to install a non-condensing boiler if you want to.

http://www.odpm.gov.uk/pub/731/Guid...tProcedureforDwellingsPDF1258Kb_id1130731.pdf

You can also find a copy of the Building Regulations Part L (doesn't actually say much) & the associated Approved Document (which supplies the actual details) http://www.odpm.gov.uk/pub/730/Appr...rindwellingsAmended2005PDF978Kb_id1130730.pdf
on the same site.

Thanks for those links JDEY I have been looking for that first one for ages

 

[jdey]

No problem, slugbabydotcom.

As you can probably tell from this thread, the guidelines can be useful to DIYers who don't want a condensing boiler. e.g. in my case it would cost a fortune to re-site my boiler. However, from a plumber's perspective, they'd like the extra money, so are less interested in following the guidelines and carrying out a professional assessment.

From a legal perspective, these regulations open up a minefield of debate. Dependent on wind conditions, a condensing plume could impinge on your neighbours property, and your neighbour could then demand a re-siting of your boiler. This, of course, opens up further work opportunities for your plumber so if you do have the work carried out make absolutely certain that there's no chance that a visible plume will impinge on your neighbours windows, doors, pathways etc. A plume diverter kit may ensure this but adhering to the 2.5M mininum is the safer option.

 

[ChrisR]

The key point to remember about flue siting is that the only difference between the 'plume' from a conventional gas boiler and that from a condenser, is that the condensation makes the plume visible!

Not it is NOT the only difference. Very importantly, the flue products from condensers are cooler, therefore less inclined to make a quick exit from the scene.

A plume diverter kit may ensure this but adhering to the 2.5M mininum is the safer option.

Plume Diverting kit can entirely remove the problem, eg by taking the exhaust up to above gutter level
"Adhering to the 2.5M mininum" doesn't guarantee that there will not be a nuisance and is NOT the safer option.