Relining chimney flue for solid fuel

[glenlloyd]

I've been wanting a small wood stove in the basement for several years. This year I finally installed a new high efficiency furnace and water heater so that I could use the chimney for a wood stove.

Originally I thought the liner was sufficient but after looking at it closely it appears to be part / all aluminum liner for gas only, so I'm now looking at the prospect of relining the chimney.

Fortunately, this chimney is a straight shot, one storey, so it shouldn't be any more than say 22-24' of flue from the basement through the top. The inside is roughly 13"x13" so a 6" liner should be sufficient. The chimney has a good draft.

I'm looking for advice on this project, what you've all used for this if you've done it and whether you found the product local or had to order online etc?

Any advice is appreciated!

steve a

[rlaggren]

I work as a plumber and we need to confront a flue once in a while; a few years ago I also looked at upgrading the chimneys in my mothers house in Chicago.

I have never come across aluminum liners but I have repeatedly found stainless steel recommended or required, especially when an oil or wood burning appliance was converted to gas. Gas flame products are much lower in temperature and higher in water content than oil or wood and thus they don't heat up a chimney (or flue) as much and the water condenses out, mixes with other gases and turn acidic and eats the old brickwork. Hence most local authorities require stainless steel liners installed when a gas replaces some other fuel. I'm referring to "regular" gas appliances, not "high efficiency" unit which are a whole other story.

My first thought is to try to see if the flue liner is already stainless steel. If it is, that may be sufficient. I don't right off think of the quick easy definitive way of knowing...

I can recommend http://www.heatinghelp.com. This guy must be King of Blarney, but he has always had good info and he shares it. If there is nothing directly relavent on his site, I suspect a question on one of the forums would get good results.

Combustion gas (smoke) temperature and composition make up a big part of flue design. Newer high efficiency wood stoves, especially pellet stoves send less heat up the flue than before and if the flue is particularly large, even a regular prefab fireplace or wood stove may not get it hot enough to carry combution products, especially creosote, though the flue w/out condensing out. Hence you may want to install a smaller flue even if the one you have _might_ work. I don't know how the calculations work here, but these are the considerations I remember from my "chimney studies".

As I understand it part of wood stove flue design is to make it possible to survive a chimney fire, since most wood fires deposit creosote in their flues and few people actually maintain their chimneys. You probably know, but JIC, creosote burns _very_ hot and the flue is like a little blast furnace.

Wood fires are very nice - just about worth all the trouble. <g>

Rufus