Big Chimney

[Aish haTorah]

I am new to this forum- just signed on because I can't find an answer anwhere else. I am replacing an old pre-fab fireplace ("Majestic") with a Napoleoan 1100 woodstove. The fireplace flue is 10"; the Napoleon is 6". My major issue is the chimney- it has an interior diameter of 10", and the exterior looks to be about 18"! What kind of a chimney is this? and can I use it safely?

 

[jtp10181]

NO!

I am wondering what you are doing exactly to "replace" the built in fireplace with a free standing stove? Sounds like a lot of work but people do it. Just wanted to make sure this is really what you are doing.

Anyway.... you CAN NOT use that old chimney. It is air cooled and designed and tested ONLY for specific fireplaces. You will need to tear it all out and replace it with Class A.

 

[Aish haTorah]

Thank you for the reply- the existing fireplace is a free-standing open fire place; sort of like a wood stove that's open on 3 sides with a metal mesh curtain. It's easy to remove- just take off the pipe and haul it out!
Does the existing chimney sound like a triple- wall?

 

[swestall]

Is the ID 10 inches, what comes out the roof? If you are purchasing this from a dealer, have them take a look for you.

 

[jtp10181]

Sounds like a scary setup. Yes the existing chimney sounds like good old Majestic triple wall air cooled chimney. It is probably only rated for 1700 deg at the most, and a EPA wood stove needs 2100 deg. It might be possible that you could run a liner through the old chimney. Is there a wall thimble or something or does the majestic pipe just come through the ceiling right into this "fireplace". I would LOVE to see pics of this if you have a digi cam.

 

[JohnnyBravo]

what is the chiney made of? class A is roughly 10" outside diameter, maybe one could squeez a new chimny inside the old one. i know you don't get yur two" clearance but the old chimney is not combustable. just a thought.

 

[Aish haTorah]

Again, thanks for all the help. I don't know all the terminology, but there is a sheet metal box attached to the ceiling from which the 10" pipe comes into the room. So you don't think this chimney will stand up to even light use?

 

[jtp10181]

If this chimney is unknown, and in unknown condition I would not recommend ANY use until you have a professional (sweep or stove dealer) inspect it and figure out what you have and what your options are.

 

[Aish haTorah]

Thank you, Feuermeister; I'll have it checked out. Is it possible to put a liner in an existing metal chimney? I'm trying to save a few bucks while still being safe.

 

[jtp10181]

It sounds like it comes down to a thimble or ceiling support box at the ceiling level, if that's the case you may be able to line the chimney from there up and use single or double wall from the ceiling down to the new stove. It would require someone who knows what they are doing, and a few odd parts but I think it could be done. Without pictures I don't know if you have a support box or just a ceiling fire-stop with pipe coming straight trough it.

 

[DiscoInferno]

Sounds like a scary setup. Yes the existing chimney sounds like good old Majestic triple wall air cooled chimney. It is probably only rated for 1700 deg at the most, and a EPA wood stove needs 2100 deg. It might be possible that you could run a liner through the old chimney. Is there a wall thimble or something or does the majestic pipe just come through the ceiling right into this "fireplace". I would LOVE to see pics of this if you have a digi cam.

My Majestic WMC42 has an 8" ID HT2100 triple-wall air-cooled chimney. I think the OD is 14". But I think it's the exception in Majestic's line, not the rule.