Liner install. Getting it through the damper.... cutting the damper... ovalizing?

[mhrischuk]

I haven't found a clear post on what people do at the damper when running a flex liner.

One fellow told me he removes the damper control then he takes a sawzall and cuts out the mortered-in frame only in the center area to make enough room for the liner to fit.

I also have been reading about ovalizing the liner and oval to round adapters.

Is there a preferred method?

I perceive it as this....

1) Measure the width of the damper opening.

2) Determine the amount of "squeeze" required to get the liner through the damper frame.

3) If it's too much (how much is too much) then the frame needs to be hacked away?

4) If it looks feasible, oval the liner as far back as required, drop the liner down the chimney and feed it through the damper frame.
Once the chimney top has been finalized, cut the stove end of the liner to length taking into account the liner to stove adapter.
by hand, squeeze the end of the liner back to round and attach the adapter.

What does an oval to round adapter look like and is it ever necessary?

On edit.... I did find a topic here https://www.hearth.com/talk/threads/42839/


Also this one. This is exactly the damper I have. https://www.hearth.com/talk/threads/42037/


I guess the big question is, if there are no negatives to ovalizing the liner, why do installers so often destroy a perfectly good fireplace damper install when they only have to crush the liner some? Is this the so-called "professional" method?

 

[michaelreinard]

I'm not an expert on this, bud I did do it myself and it was a pain. I removed the damper plate, which left about a 6" opening in the cast iron damper assembly. I used an angle grinder to cut away at the assembly and make more room for the liner. (I needed a lot more room because the angle of the damper is not the same angle that the liner was coming down.) Then I dropped the 30' of liner down the chimney and tried to set it up. However the angle just wasn't working for me. While the liner was flexible, it wasn't flexible enough to get it to go into the insert at the right angle and make a good seal. I pulled the liner out a bit, cut some more away from the damper assembly, and tried it again. I still didn't feel comfortable with the seal. Eventually I bought one of these and I felt much better about it.
http://www.chimneylinerdepot.com/st...5-Degree-Flex-Liner-Elbow-Non-Adjustable.html

So from my experience, at least with an insert where you don't have a lot of clearance between the damper and the stove, you can try to precisely measure and cut the perfect oval, but you'll probably need to cut a bigger hole so you have more room to wiggle the pipe onto the stove.

At the end of the day I had a big hole with a liner coming through it, and I used mineral rock wood and an aluminum to "seal" the chimney throat above the stove.

I'm interested if anyone else has any thoughts on this.

Mike

 

[Wood Heat Stoves]

Chimney liners come in round and oval sections. If you need to go through an oval damper area then you could use an oval section, then go to round. You shouldn't crush the liner to fit, though, and some liners, like Dura Liner which I would recommend, are 2 wall and can't be squeezed. In many cases the damper has to be cut out with a torch, which means you can't use the fireplace as a fireplace again.

 

[mhrischuk]

Chimney liners come in round and oval sections. If you need to go through an oval damper area then you could use an oval section, then go to round. You shouldn't crush the liner to fit, though, and some liners, like Dura Liner which I would recommend, are 2 wall and can't be squeezed. In many cases the damper has to be cut out with a torch, which means you can't use the fireplace as a fireplace again.

How does the physical connection from oval to round work? Is it a metal adapter? I'm seeing pictures of a piece of liner with one end oval and the other end round. Do you simply slip the liner over the other liner? Sealant needed? Screws?

Pictures of this install anyone?

Thanks,

Mike

 

[tickbitty]

A lot of us just cut out the damper (or had it cut out) with a sawzall. It is not terribly complex, and if you or anyone else ever wants to use the fireplace again a top-sealing damper can be installed for not too much $.

 

[mhrischuk]

A lot of us just cut out the damper (or had it cut out) with a sawzall. It is not terribly complex, and if you or anyone else ever wants to use the fireplace again a top-sealing damper can be installed for not too much $.

Thanks.

I think that is what I'm gonna do.

 

[kylej]

I thought I'd bump this thread as I'm having the same issues. I have been able to widen the damper opening with an angle grinder, but my fireplace has iron lining (sleeve?) that continues up beyond the smoke shelf a foot or two before ending into the terra cotta. This sleeve is kind of star shaped (imagine a square that has each of the four sides pushed in from the center). I'm not sure if it was like this originally or if it warped over the years (this is in a masonry fireplace built in the 60's). I'm having a heck of a time getting up there with a grinder, sawzall, etc. Anyone have any suggestions? I'm using a double wall insulated liner, and my plan was to cut off the outer layer an insulation to get it through the maze at the bottom of the chimney, but I'm afraid to ovalize too much.

How much ovalizing is too much? Do I need to give up and call someone in with a torch?

 

[NCredneck]

I just did mine yesterday for an install. I used a cutting disk on an angle grinder to cut out enough of the damper to get the liner through. Just do yourself a favor and cut several inches more than you think you will need, I didn't and it was aggrevating tight.

 

[NCredneck]

And I also decided if I ever go back to using the fireplace to burn wood it may be easiest to have plate steel welded back in vs replacing it with a new one.

 

[cygnus]

I ovalized my 6" flex liner through the 4.5" opening. I really wanted to keep the fireplace intact for resale. I used a 2x8 and gently 'smooshed' it a bit at a time until I got to 4.5" for the last few feet. Not easy but I think it was easier than cutting out the flue. Once I got it all thorough, I did have to re-round the end to fit on the appliance connector and onto the insert. I think that was the hard part. I used a ridiculous combination of small boards and clamps to squeeze it round again. It worked in the end and the liner still has plenty of structural integrity which might have been a concern.

I was concerned about draft but I can say that I think I have too much draft. The chimney is about 30', insulated liner and high enough to be away from obstruction. It might have been a problem under lesser conditions, I can't say. I haven't cleaned the liner yet so don't know if creosote builds in the area much I doubt it.

Hope this helps.

 

[Hogwildz]

I cut the damper are out to accommodate the new 6" round liner. Used a sawzaw & angle grinder. Very messy, and mine took some effort. I am not that flexible to contort my body in that space, but did it anyway.
Here is a link to how I did mine.

https://www.hearth.com/talk/threads/5084/

 

[granpajohn]

The flex liner manufacturer has a statement in their specifications about ovalizing. I summarize viz:
"Ovalizing is fine, but don't squish it too far". They have cross-sectional area numbers, and etc., but that is basically it.
I talked to the vendor by phone because of items I had read, and also some vendors will ship the liner pre-ovalized. I'm sorry I don't have a link ATM, but I seem to recall 4" being the bottom line for 6"liner.

So anyway...to squeeze it back to round. Like Cygnus, I used some clamps and wood pieces, but in the end, the best trick was to take a set of limb loppers, (I have a very strong one...luckily), and place it in between the handles, and squeeze. Wish I had thought to try it from the beginning.

Amazing how strong that flexible stuff turns out to be.

 

[cygnus]

So anyway...to squeeze it back to round. Like Cygnus, I used some clamps and wood pieces, but in the end, the best trick was to take a set of limb loppers, (I have a very strong one...luckily), and place it in between the handles, and squeeze. Wish I had thought to try it from the beginning.

Me too! That's an excellent idea! Where were you last year?!?!?!? LOL

 

[EJL923]

I believe i have a pretty standard damper area, 6 or 7" in height. I dont know what standard is. The flex liner was naturally ovalized from being wound up. it fit throught the damper with some slightly more ovalizing and then connected it to the stove by sqeezing it back into a circle. no kinks or anything.

 

[Rudyjr]

In many cases the damper has to be cut out with a torch, which means you can't use the fireplace as a fireplace again.

Sure you can with a chimney top damper like Leymance. I am a welder and I have never seen a damper throat (done many) that took more than a grinder with a cut off wheel and a few good whacks with a hand sledge. I would never use a cutting torch in a house. Just my 2 cents.

 

[FireAnt]

Small BIL and an angle grinder. Cut a small notch.

 

[sksmass]

I too really wanted to avoid cutting my fireplace damper "just in case" I ever wanted to go back to a fireplace. It just wasn't possible for the install though. I ended up cutting a section out of the damper frame with an angle grinder to fit my 6" liner through. I saved the cutoff piece of metal in case someone ever wanted to weld it back in place. But that someone won;t be me. I'll never go back to an open fireplace. You'll forget about the damper once you live with your woodstove for a couple of seasons.

 

[FireAnt]

As sksmass did. I also saved the piece in case someone wanted to weld it back in. If I ever sold my house the stove would likely go with it.

 

[granpajohn]

You'll forget about the damper once you live with your woodstove for a couple of seasons.

Agree.
FWIW...Don't know about other manufacturers, but my Quadrafire came with a metal plate to be placed in the old fireplace with a warning statement...loosely summarized:
"It may not be safe to use this fireplace again; it has been modified"....

Clearly lawyer stuff.