Woodburning stove external air supply

eoghan1985

Just looking for advice/ideas to get external air supply to my stove. Done some googling but turned up nothing.

Stove sits in flat roof extension, nowhere near external wall. The exhaust flue goes straight up through roof so I was thinking if there was someway to run the 100mm inlet straight through roof as well it could work.

Has anyone done this?

Outkast_IRE

I have only seen it done 2 ways - in the floor slab or the external wall behind the stove location.



You should check the technical literature with the stove as i am sure there will be some sort of limit on the length of duct/pipe for the fresh air intake.

eoghan1985

Ya, googling it it seems to normally be done the two ways you said, but I'm not able to do either. In tech manual there is no specification for max duct length.

If I were to do it there would be 90°bend out of stove back (it's freestanding stove) and vertical 2.5m run through roof with rain damper on top so doesn't seem too long. Just don't know what sort of pipe to use that would be suitable

Outkast_IRE wrote: »

I have only seen it done 2 ways - in the floor slab or the external wall behind the stove location.



You should check the technical literature with the stove as i am sure there will be some sort of limit on the length of duct/pipe for the fresh air intake.

Ubbquittious

It would seem strange to think there would be a maximum length as such. 100mm is quite a wide pipe and its hard to imagine it wouldn't be able to supply the air required for a normal stove at any length. Though it might work I'd avoid going through the roof if at all possible, the reason being you are sucking air from above down into a place that is warm. This could give trouble particularly if there isn't a great draw from the chimney

Outkast_IRE

Ubbquittious wrote: »

It would seem strange to think there would be a maximum length as such. 100mm is quite a wide pipe and its hard to imagine it wouldn't be able to supply the air required for a normal stove at any length. Though it might work I'd avoid going through the roof if at all possible, the reason being you are sucking air from above down into a place that is warm. This could give trouble particularly if there isn't a great draw from the chimney

It depends on the air requirement of the stove which would be linked to it's heat output etc. But most fuel burning appliances would test for things like this to minimise the likelyhood of any accidents down the line . I see that most of the manufacturer's just reference that there is no hetas guidance at the moment, but correctly note you must be careful where the fresh air inlet is as wind pressure can effect it, I would stay away from a roof fresh air inlet for this reason

eoghan1985

So it prob wouldn't work so because of wind etc?

There is the start up grill that provides primary air from room to be used during lighting and then closed when fire is hot. The draw from stove when going is good anyway so there shouldn't be any issues there

Roen

I know of one example that has the pipe brought into the attic. Teed off there and pops out through the soffit on both sides of the house. That gets about the negative pressure thing. No idea how it gets from the stove to the attic mind you.

Mine goes in a sweeping 90 bend out behind the stove and pops through the wall. I think it's only 75mm / 3" pipe. Does yours require a 100mm?

eoghan1985

The manual says that it has an 100mm opening at rear. I've never taken off the little plate covering it to look so I'm just going by that.

Not sure of any way I'd be able to get to attic as it's in an single storey rear extension