condensing boiler exemptions - flue over a walkway ?

[.]

we've been asked to install a ch system in a second floor flat and the most likely place for the boiler to go will mean that the flue will exit over a walkway.

due to the possibility of water condensate freezing in winter

- if it might even remotely possibly do so it must be taken into consideration - it might be granted an exemption certificate but corgi technical help suggested that building control be contacted to ask their opinion.

we can see a game of ping pong developing between corgi and BCO so we're wondering if anyone had any experience of a similar situation ? car ports are one example of possible "condensate puddle freezing into ice hazard" problems.

anyone ?

[Christian McArdle]

I wasn't aware of a restriction that prevents flues being positioned at that height. I imagine most flues exit above a point that might be walked upon.

Christian.

[.]

corgi technical support are fully aware :-(

thing is, it's semi-warden aided complex, the customer bought the flat from the council before the council put free GCH in for everyone pre april 05 law changes, all non condensing combis, obviously.

pensioners will be doddering along the walkway so it /must/ be safe as well as be done by the book. was hoping someone else has encountered this sort of issue with local authorities. forewarned is forearmed, etc.

[Ed Sirett]

The condensate should drain back into the boiler. The flue should be installed so it does this. There may be a few drips from the flue but frankly the idea that they could form into a hazardous glacier is frankly absurd.

[Ed Sirett]

What happens to rain drops?

[.]

I agree, best mate (corgi reg'd) agrees, corgi technical help told mate to contact BCO for their opinion. /shrugs/ that's why I thought I'd throw it open in here. mate is rechecking the regs tonight anyway, just thought I'd canvass for opinions.

are you corgi reg'd btw, I'm assuming you are.

[.]

ah, my bad: more info. it's not the condensate which may be problematic it's the flue pluming onto cold concrete about a foot above the flue which will be venting over a walkway. the concrete is painted and, obviously, can't suffer any damage in the long term as it belongs to the council.

[<me9]

Could the flue not be extended past the concrete?

[.]

fingers crossed we can come up with something like that but it's crossing local authority property. might just pass on the job if it's too much of a 'mare. there's 2 other installs lined up :-)

[John Rumm]

Well if you think about it, a conventional boiler ought to be *worse* in this case. The vapour content in the flue will actually be greater (i.e. the boiler will be manufacturing the same amount of water (or in fact clightly more due to more gas usage), and none of it will be being extracted from the flue gasses before spitting them out at your concrete. The concrete will have enough thermal mass to cause some condensation of the (hotter) flue gasses.

The only real difference with the condensor is that the vapour will be visible. You may find that if this were a small enclosed walkway, the the amount of local "fog" created might be undesireable.

There is an assesment document that explains how the expemtions work, howver since the demise of the ODPM web site I don't know where it now lives!

[Ed Sirett]

Now this is a problem. Time to use a boiler with a versatile flue system...

[Gav]

i shouldnt have thought the flue will be allowed to 'plume' to the underside of a walkway, i think you need to explore the limits of flues by manufacturer(what boiler is it?) and the find the correct size boiler!