1878 unlined chimney - ok with two liners?

[1878]

I have a two story italianate in Minnesota. It has an unlined brick chimney on the interior side of the exterior wall. It houses an aluminum liner from the boiler and water heater in the basement.

I'd like to add a wood stove on the first floor into a SS liner in the chimney. Is this ok?
I've tried contacting the city permit office to inquire about their rules for permitting and inspecting and they told me it was up to me to develop plans and then they would say if it is ok for me to install.

One local stove shop told me it was ok if I used two SS liners, they would replace both. I am wondering if they just want to make an extra buck by doing both. I'd insulate the wood stove liner, so the liners wouldn't touch anyway.

What are your thoughts? What does NFPA say?

Thanks in advance

 

[fire245]

I have a two story italianate in Minnesota. It has an unlined brick chimney on the interior side of the exterior wall. It houses an aluminum liner from the boiler and water heater in the basement.

I'd like to add a wood stove on the first floor into a SS liner in the chimney. Is this ok?
I've tried contacting the city permit office to inquire about their rules for permitting and inspecting and they told me it was up to me to develop plans and then they would say if it is ok for me to install.

One local stove shop told me it was ok if I used two SS liners, they would replace both. I am wondering if they just want to make an extra buck by doing both. I'd insulate the wood stove liner, so the liners wouldn't touch anyway.

What are your thoughts? What does NFPA say?

Thanks in advance

(broken link removed to http://www.nfpa.org/codes-and-standards/document-information-pages?mode=code&code=211). You can view nfpa 211 for free. Personally if I was doing the install I would want the existing liner to go to ss and not be aluminum. Iam out of the showroom for the weekend but can look in the ul book too on monday if u get jammed up.

 

[begreen]

I would guess it would be ok with an insulated stainless liner for the woodstove. It's best to ask the local inspecting authority.

 

[bholler]

I personally would never have put in aluminum they just dont last very long at all but as long as the ss liner is insulation wrapped it shouldn't shorten the life of the aluminum any

 

[begreen]

That's the first I have heard of this. Just how long do aluminum liners last for gas appliances? One would think it would be in 10s of years in order to be approved for this common use, but apparently not. After reading up a bit on aluminum liner failures due to corrosion I agree. It looks like they have a life of about 5-7 yrs. That's way too short.

 

[bholler]

Just how long do aluminum liners last for gas appliances?

That depends on the type of furnace there are several classes of gas furnaces. And only one is approved for aluminum liners (even though gas guys put them on everything). But even on that class it is not uncommon to have a failure in ten years. But i have replaced them on some in 2 years.

 

[begreen]

Good info. I've never had an aluminum liner or put one in. A quick google search showed them lasting typically only 5-7 yrs, with earlier failures reported.

 

[bholler]

Good info. I've never had an aluminum liner or put one in. A quick google search showed them lasting typically only 5-7 yrs, with earlier failures reported.

We dont put them in either the only aluminum we install is for fresh air intakes. There have been several that we have bid on and the customer said but the gas guys will put in for half that then a few years down the road they call us to replace the aluminum

 

[1878]

The aluminum might be rotten by now then, has been installed 30 years ago I believe, when the boiler was put in place...

Yeah, the inspecting authority is relying on me to come up with a plan that they will review and then approve if it looks ok. I was hoping to get some good information from you guys...

 

[bholler]

Well you need to have that aluminum liner inspected before going any further with any plans. And if i was the installer and the aluminum one was that old i would probably insist on replacing it i would be afrain that when i pull the new ss liner the aluminum one would just fall apart then i would have to put in a new furnace liner for you out of my pocket

 

[Jo191145]

The aluminum might be rotten by now then, has been installed 30 years ago I believe, when the boiler was put in place...

Yeah, the inspecting authority is relying on me to come up with a plan that they will review and then approve if it looks ok. I was hoping to get some good information from you guys...

Well a good liner should easily take the place of a standard clay flue liner. The only question I can think of is would any inspector insist there's a partition wall between the two like is required in masonry. Seeing as liners are one piece units I should think it's not required but I only know masonry codes.

You could ask this question of your local inspector but run the risk of him answering Yes. Either he's not a very helpful public official or he doesn't have the answer himself and is hoping you find it. Ditch the aluminum.

 

[begreen]

If the stove liner was insulated it seems to me that would be enough barrier.

 

[bholler]

I agree with you begreen no problems as long as its insulated and the aluminum one is ok

 

[begreen]

Just to clarify, I agree with replacing the aluminum liner too. At 30 years into service there is no point in taking any chances. Replace it with a new stainless liner.