Can a boiler flue be extended?

mozzy10

I had a combi boiler fitted a few years ago. I live in a bungalow and the flue is situated right under the "eaves" of the house. At the time I thought the flue was a bit too short but the installer assured me it was the only flue you could fit.

The thing is, it is spewing out steam which is going up under the eaves. It condenses and drips down. This cant be good for the eaves can it?

Can a longer flue be fitted so it extends past the eaves out into the air?
Cheers

ormus

what make model is the boiler.
you need to read the installation manual. they give precise specs re the siting of the flue termination.
ie on the vaillant its a minimum 200mm below the eaves.
longer flues are available. up to 25m.

mozzy10

It is a Saunier Duval Thema Condens F24e

It could do with being about 15cms longer so the steam is "pushed" away from the eaves. I am worried that the wood will be going rotten.

roger196

Where the terminal is less than 1metre below a plastic gutter or less than 500mm below a painted surface, a suitable one metre long heat shield should be fitted.
p214 of Essential Gas Safety 2nd edition published by CORGI.

You will need to check the current recomendations by contacting Gassafe.

keystone

Yes you can - Saunier Duval do extension kits and plume management kits for this. Probably about £ 100 in bits plus install. Contact the RGI who services it for you.

Cheers

mozzy10

Thank you for the replies. I will get a gas man to come and look at it, give it a saftey check and (hopefully) fit a longer flue.

mozzy10

OK, so the gas man has just left. He told me he could not fit a longer flue pipe. There is only supposed to be a short length of it sticking out the side wall of the house.

I can't find anything in the manual about how much can be on the outside of the house.
It does say that plume management kits can be used.

He theorized that it would have originally been 1 metre long and would have been cut down in size by the original fitter.

His suggestion were
1 to fit a vertical flue going up through the roof tiles - £225
2 to drop the boiler down about 9 inches and reuse the same flue pipe just lower down on the outside wall - £175

Dropping it down was cheaper but would mean it virtually sits on the worktop.

Here is a picture of it


The damage to the roofline was caused by the old boiler flue warping the plastic.

This side of the house is next to the driveway.

Any suggestions on what to do?
Can the pipe really not be replaced by a longer piece?

Ben84

That is definitely installed badly, gas fumes should be leaving your house somewhere that they can disperse in to the air, not scorching something or collecting somewhere that they condense and make a damp patch. The boiler manual probably won't tell you much, but the flue kit would have had instructions advising about clearances. I'd be very surprised if this installation wasn't significantly less than suggested. So, I'd start with a complaint to the original installer.

Owain_Moneysaver

The installation manual appears to be this one here. Flue details are on p. 23.

It looks as though you should be able to go horizontally out, 90deg angle up, vertically up to a vertical flue terminal as described in 5.8.2 subject to max flue length.

Canucklehead

Hi,


Looking at the photo I would say you won't get the flue at the right angle to get the condense to fall back to the boiler without clashing with the fascia.

If you lower the boiler you won't meet the minimum clearance underneath the boiler (depending on your definition of 'virtually sit on the worktop')

Answer: vertical.

Like it should have been in the first place.

GSR.