Update: Advice Needed:ZC Majestic Fireplace with Triple-Wall "air cooled" Flue

[CJRages]

Hello again,

On Saturday I popped the top off our ZC fireplace chase to check what type of venting system I have. It turns out to be the triple wall (air cooled system) for ZC fireplaces.

Please correct me if I'm wrong: I understand that the two spaces between the three walls of the chimney act as air passageways to help cool the inner pipe. Cool air travels down from the top of the flue between the outer and middle pipes. When the cool air reaches the bottom of its channel near the FP, it enters the space between the middle pipe and innermost pipe. It rises from this point up and out the top of the flue carring heat as it goes.

If this is indeed the case, it is still recommended that I install a 6 inch stainless steel liner down the inner(8 inch) pipe in order to hook up to a zero clearance rated insert such as the Pacific Energy - Pacific Super. As long as the insert fits within the existing firebox and ALL clearance requirements are met.

Am I safe to proceed?

Any questions or comments are greatly appreciated.

 

[brokeburner]

that triple wall setup is tuff i used to have the same one i had a hearth stove slammed into my majestic zc fireplace. Dont recomont doin it that way but i never had no problems when mine was like that.

 

[DAKSY]

You still hafta insulate the liner, because the clearance to the triple wall is 2" to combustibles.
Too close for the heat from your liner without the wrap...

 

[CJRages]

Yes. Like you are saying the stainless liner will have to be the insulated type.

Anyone have any comments about installing a liner and hookup of an insert within a zero clearance fireplace? Is this a simple enough DIY project or should I consider having a professional sweep do the installing?

Attached are a few pictures for thought... these were taken by my home inspector before we bought the house about 2 months ago.

The large wood burning insert sitting in the FP will be replaced with an approved ZC wood burning insert.

I'm still feeling a little unsure about the safety and performance of this idea. Any thoughts are appreciated.


EDIT: As another note - the chase cover is rusted badly. Should I use some type of rustolium paint or replace?

 

[DiscoInferno]

(I've posted this several times before on other threads, but it keeps coming up.)

What is the Majestic fireplace model? The WMC42 (and maybe some others) uses a triple-wall chimney like you describe that is actually tested to the HT (2100) spec. It's their "type S" or "S8" chimney, and is also used on the VC Sequoia EPA fireplace. Look on the fireplace faceplate (mine says "S8"), since I don't know how long they've been using that particular chimney and yours seems a lot older than mine. As I read it, this means technically you don't even have to line it (although it's clearly recommended and depends on local code) and if you do line it you don't need to insulate it. With mine I went with a direct connect to a free-standing Fireview: https://www.hearth.com/econtent/index.php/forums/viewthread/39969/

Re: the chase cover - I would replace if it is rusted all or nearly all the way through. We had a similar situation and it caused a lot of water damage and rot in the chase and adjacent wall.

 

[CJRages]

(I've posted this several times before on other threads, but it keeps coming up.)

What is the Majestic fireplace model? The WMC42 (and maybe some others) uses a triple-wall chimney like you describe that is actually tested to the HT (2100) spec. It's their "type S" or "S8" chimney, and is also used on the VC Sequoia EPA fireplace. Look on the fireplace faceplate (mine says "S8"), since I don't know how long they've been using that particular chimney and yours seems a lot older than mine. As I read it, this means technically you don't even have to line it (although it's clearly recommended and depends on local code) and if you do line it you don't need to insulate it. With mine I went with a direct connect to a free-standing Fireview: https://www.hearth.com/econtent/index.php/forums/viewthread/39969/

Re: the chase cover - I would replace if it is rusted all or nearly all the way through. We had a similar situation and it caused a lot of water damage and rot in the chase and adjacent wall.

Thanks for the info. DiscoInferno.

That is surprising that there are ZC fireplaces that are rated to 2100 F! Good for you.

I've looked at the small metal plate on the inside right of the fireplace. The small plate hasn't held up very well. I got the five digit serial number which was engraved in the metal, but a lot of the text that was printed on the identifier is gone - burned or worn away. :-S
I may try contacting Majestic to try to identify the fireplace via serial number. It's worth a shot I suppose.

Why do you say that insulation is unnecessary for a flue liner in this situation? I'm guessing that by the time you have four metal walls between heat and combustibles it is getting close to being safe. Lol...

 

[DiscoInferno]

My BIS Ultima EPA fireplace has a double-wall air-cooled chimney that is specifically made by Security for that fireplace. So the number of walls isn't even that important. As I understand it, you don't need the liner to meet the HT spec on its own (i.e. with insulation) if the chimney already meets it. But if it's old and you can't figure out what the chimney model is then an insulated liner is your best bet.