Wood stove install into gutted zero clearance cavity.

[snobuilder]

I'm a new guy here. I found this site while researching my project to install a lws2200 high efficiency wood stove into my northern WI home.
I currently have a zero clearance fp with a little used perfectly good 8" ID triple wall chimney. My plan is to gut the sheet metal fp back to the walls and top sections leaving the chimney flue in place. The measurements look to be ok to then slide the wood stove into the alcove created by the gutting of the old fp and simple connect up to the flue with a 6x8" adapter....possible a 6x7" to fit into the damper ledge.
Looking for input as to if this is a dumb idea or pure genius.

 

[bholler]

I'm a new guy here. I found this site while researching my project to install a lws2200 high efficiency wood stove into my northern WI home.
I currently have a zero clearance fp with a little used perfectly good 8" ID triple wall chimney. My plan is to gut the sheet metal fp back to the walls and top sections leaving the chimney flue in place. The measurements look to be ok to then slide the wood stove into the alcove created by the gutting of the old fp and simple connect up to the flue with a 6x8" adapter....possible a 6x7" to fit into the damper ledge.
Looking for input as to if this is a dumb idea or pure genius.

What are the alcove clearance requirements of your stove? The chimney you have most likely is not rated for high enough temps for a woodstove

 

[begreen]

This is an unshielded, radiant stove. It has no alcove specification. With side clearances of 23", rear clearance of 16" and an R=2.0 hearth requirement, it's not a candidate for alcove installation. There are no clearance exceptions mentioned in the manual.

 

[snobuilder]

Just so we are clear, the metal walls, top and bottom of the pre- fab fp will remain in place so any clearances will be to a non cobustable surface that was designed to have a fire directly on it as a "zero" clearance unit.
I doubt I will have an exact rating on what the triple wall ss flue pipe is but it was obviously built to specs that would handle a roaring hot wood fire. No?

 

[DAKSY]

That ZC chimney is NOT rated for the temps your wood stove needs for safe operation.

 

[bholler]

Just so we are clear, the metal walls, top and bottom of the pre- fab fp will remain in place so any clearances will be to a non cobustable surface that was designed to have a fire directly on it as a "zero" clearance unit.
I doubt I will have an exact rating on what the triple wall ss flue pipe is but it was obviously built to specs that would handle a roaring hot wood fire. No?

Thats not how it works. First off you said you were hitting the fireplace so the surface intended for fire will be gone. But regardless you can't just shove a stove in a prefab fireplace that isn't designed for it.

So you still have combustibles behind that thin layer of sheet metal your clearances are to those.

And yes that pipe might work fine unless you have a chimney fire. In that case you are going to exceed the maximum temperature by 500 +degrees.

 

[begreen]

Just so we are clear, the metal walls, top and bottom of the pre- fab fp will remain in place so any clearances will be to a non cobustable surface that was designed to have a fire directly on it as a "zero" clearance unit.
I doubt I will have an exact rating on what the triple wall ss flue pipe is but it was obviously built to specs that would handle a roaring hot wood fire. No?

That does not reduce clearances in this circumstance. The manual does not offer clearance reduction as an option.

The chimney temperature specs for an older fireplace often were lower than what is required for a modern woodstove. They are not equivalent.

 

[snobuilder]

Ok thanks for the input. From what I have researched the existing triple wall chimney is good for 1000F continuous use and tested up to 1700F. To be on the safe side I will extend a section or 2 of 24ga. stove pipe up into the triple wall to dissipate excessive heat up into the flue to be on the safe side.
There will be a gap even at the back corners of the new stove to the sheet metal walls of the old ZC unit.

 

[bholler]

Ok thanks for the input. From what I have researched the existing triple wall chimney is good for 1000F continuous use and tested up to 1700F. To be on the safe side I will extend a section or 2 of 24ga. stove pipe up into the triple wall to dissipate excessive heat up into the flue to be on the safe side.
There will be a gap even at the back corners of the new stove to the sheet metal walls of the old ZC unit.

The chimney for a woodstove needs to be rated to 2100 degrees. And again you cannot put a stove in the gutted shell of a pre fab fireplace. It would be extremely unsafe with a very high risk of a structure fire.

 

[bholler]

Your initial post asked for input on whether this was a dumb idea or genius. You have your answer it is without question a dumb idea.

 

[wjohn]

I was in the same boat as you - ZC prefab fireplace, 8" chimney (mine was air cooled), and wanting to replace that inefficient, air sucking piece of garbage with a stove. Ultimately there was nothing I found that I could salvage from it. I ended up ripping everything out of that corner of my house, removing the chimney, patching the roof and ceiling, and putting the new 6" chimney farther away from the corner as trying to reuse the existing holes from the old chimney wouldn't have met clearance requirements to walls and trusses for any stove/6" UL 103 HT chimney system I could find.

I definitely found several issues from the original install - in several spots they weren't even meeting clearance requirements for that specific prefab fireplace and chimney system. I can't imagine hooking a stove up to it. Sometimes you get lucky, but I sleep much better at night knowing I put the new stove and chimney in and followed all clearances and installation requirements to a T.

 

[Brawndo71]

I am in the same situation. ZC Heatilator, corner install. I am just going to wait another year or so to save up for the install. Hoping to just get a new high eff ZC fireplace from Valcourt/Osburn/Astria. The site is too small for the larger fireplaces. Not sold on a stove for this corner, unless something comes up during planning that there is an issue, and can't fit a fireplace. Guess i'll get some quotes to budget this out. Maybe i can do some of the demo to save some money when the time comes.

 

[PAbeech]

I went through the same thing with an old zc fireplace in a wood chase with an 8" chimney. I wanted to do something similar to you but its not possible. I just upgraded it with a pacific energy fp16 zc fireplace its awesome. They make a whole line of different size zc fireplaces, very efficient.

 

[Brawndo71]

Yes if the pipe isn't UL listed for the stove/fireplace its worthless. Either its a new high eff fireplace with new pipe, or gut the whole area and install stove with new chimney pipe. Think i can get my area to look like one of these two choices. The FP16 would fit in my spot, its on my list. All the ZC fireplaces i am looking at use 6" packed pipe. My pipe has to go thru the attic. I really like the fireplace look.

 

[john26]

I seen an ad for a used gutted ZC for sale that had an insert in it and a charred plywood base included. I wished I saved the pictures.

 

[begreen]

As the OP seems hellbent on doing an illegal and unsafe install I am going to pull the plug on this thread. It's a textbook example of coming for advice with earplugs and proceeding with the dumb plan. It sounds like it will work until it doesn't.

Actually, this whole thread should be deleted so that others don't copy, but I'll leave that up to the boss.