Remove damper "housing" or ovalize liner?

[a316co2000]

This is my second post on hearth.com, and I'm hoping it will generate as much useful advice as the first.

I recently acquired (for free) a woodstove insert and have done some work to make it look new again. I'm [almost] ready to install it in my fireplace, but I have one more hurdle to get over before doing so: the damper opening is smaller than the diameter of the stainless steel liner, and I'm not sure what the best way is to deal with that.

The outlet from my woodstove insert is 8", so I bought an 8" liner kit and an insulation kit to wrap around it. I got up on my roof with a friend to measure the length of the chimney, and while we were up there we looked down it to ensure it was clear all the way to the bottom with no obstructions. It was, indeed, clear to the bottom, but at the bottom is the damper, which is rectangular. The rectangle is plenty long enough, but it's only about 6.5" wide.

I'm military, and I know I'm only going to live in the house for the next 3.5 years. When I leave, the plan is to rent the house, but there is also a chance we'll sell. Whatever the outcome, I'd like to leave the possibility of taking the stove with me, and if I do so I would obviously like to restore the damper to the way it is now if at all possible.

I found an article here that covers two options of how to deal with my dilemma: http://www.rockfordchimneysupply.com/articles.php?article=How-to-Install-a-Liner-through-a-Damper.

According to that link, which seems to be a reputable source, I can either cut the damper housing or ovalize the liner. The link does not seem to mention pros or cons to either method. The cons to cutting the housing is that it will forever be damaged and not useable if I wish to remove the stove and liner, and I would think it would be expensive to install a new damper. The possible cons to ovalizing the liner are what worry me, and I'm hoping you guys will tell me there aren't any.

For reasons I've already mentioned, it seems like ovalizing the liner is probably my best option, but I wanted to seek a little advice here before doing so. Would ovalizing the liner disturb the integrity of it, or affect the performance of my stove at all?

Thanks again, in advance, for the advice.

 

[bholler]

Don't ovalize it. It reduces draft can possibly damage the liner makes it a pain to clean just to mention a few cons. When you cut out the damper doit a cleanly as possible and if you ever want to put it back to a fp the piece can be welded back in of just bolted in with some plates spanning the cut.

 

[a316co2000]

Don't ovalize it. It reduces draft can possibly damage the liner makes it a pain to clean just to mention a few cons. When you cut out the damper doit a cleanly as possible and if you ever want to put it back to a fp the piece can be welded back in of just bolted in with some plates spanning the cut.

What's the best way to cut it?

 

[bholler]

We try to cut it as square as possible so it will be easier to repair if need be. We cut down with a sawzall and ten across the bottom with a grinder.

 

[a316co2000]

Will a standard "metal cutting wheel" like this one work: http://www.homedepot.com/p/DEWALT-4...-Purpose-Metal-Cutting-Wheel-DW4418/202579892, or do I need something a little more intense to cut through this thing?

 

[bholler]

that will work we use thinner ones what ever you do wear safety goggles or a face shield there will be lots of sparks and possibly broken grinding wheels flying

 

[a316co2000]

that will work we use thinner ones what ever you do wear safety goggles or a face shield there will be lots of sparks and possibly broken grinding wheels flying

Thank you. I'm assuming this is a bad idea? http://nepacrossroads.com/about28842.html

 

[bholler]

if you can get the damper out it is fine to do so but most wont come out

 

[a316co2000]

if you can get the damper out it is fine to do so but most wont come out

Can I do damage by trying? I feel like cutting it I can't really do any harm, but I don't want to...I don't know....ruin my chimney by trying to pry the thing out if that's a possibility.

 

[bholler]

you could definatly damage the damper housing by trying to get it out as far as damaging the chimney I guess it is possible but not very likely.

 

[Excavator]

I cut mine with sawzall and chipped out few fire brick to make room for 8 inch

 

[Dave A.]

If/when you restore it as a working fireplace, I'd think the best option would be the type of damper that seals the top of the chimney and uses a cable that drops down the flue to the bottom for opening and closing. It will seal the whole flue and more tightly than the damper that's in there now and if you're handy enough to install a liner yourself you should be able to install that type of damper. Then you needn't be concerned about welding the old damper back into place.

 

[a316co2000]

Well the job is done and the stove works great, though the weather has warmed up so we only really used it to make sure it worked (so far).

We ended up ovalizing the last 2 feet of the liner and, once getting it through the damper hole, made the end round again to connect it to the stove. I decided to go with that method because after removing the damper (flapper part) it became evident I would have to remove some fire brick to avoid ovalizing the end of the liner, and I wasn't comfortable attempting that. Ovalizing it did make it a little tougher to get it shoved down the flue, but with a little brute force we made it work, and I feel good about being able to do the job ourselves.

I'll post some pictures once I get the rest of the trim painted and put on the stove. It already looks great, despite being at least (I think) 15 years old.

 

[fire_man]

Don't ovalize it. It reduces draft can possibly damage the liner makes it a pain to clean just to mention a few cons. When you cut out the damper doit a cleanly as possible and if you ever want to put it back to a fp the piece can be welded back in of just bolted in with some plates spanning the cut.

How do you clean an ovalized liner properly?

 

[bholler]

well we usually cut a brush to fit but in a case like this where it is only ovalized for a short section you will need to use a soot eater or two different brushes. Either way it can be a real pain which is why we never do it and I would never recommend it. We will ovalize the entire length evenly then with a brush cut to fit it is not hard to clean at all.

 

[fire_man]

My problem is if the inspector makes me insulate the SS liner I will be forced to ovalize to fit into the clay liner. I'm installing a stove outside of a fireplace, but the clay liner is offset in the smoke chamber to one side. I don't think I could bend an ovalized liner towards the stove so I might have to leave the last 5 feet not ovalized so I can make the bends. Any ideas?

Sorry to hijack the thread, but it's still on the topic of ovalized.

 

[bholler]

Well first off I am all but positive the inspector wont make you insulate it they generally don't know anything about it. I still think you should insulate it so in that case your options are to ovalize it or to break out the liners. Also ovalized liners still bend quite a bit I am pretty sure you could still make that bend. The other option is to leave the bottom round and clean it with a soot eater.

 

[fire_man]

I think I could fit 1/4" blanket and keep a round liner if that is an option.

I didn't think you could bend the ovalized, Olympia won't even ship ovalized by normal free delivery, has to be shipped on a flatbed truck for big $$.

I also didn't realize the inspector wouldn't know about insulating - but you are right after my first install they never even looked at the liner.

 

[bholler]

I don't know about the shipping we have an ovalizer so we just do it ourselves when we need it which is rarely. But yes they still bend but not near as well so I don't know how hard your offset is but it could be an issue. 1/4" is better than nothing for sure check the specs and see what clearance that gives you I don't know off hand.

 

[fire_man]

I found this on 1/4" blanket but I don't have 1" clearance from chimney brick to wood house. I'm tempted to pick the inspector's brain before I pull the permit and ask what he is looking for, and if he does not mention insulating I would go with 1/4" because like you say its better than nothing and then I won't have to ovalize.

One wrap of HomeSaver 1/4" Foil-Face FlexWrap gives you a UL 1777 Listing when you have 1" of airspace clearance from the masonry chimney to exterior combustibles.

 

[bholler]

That is not a bad idea. As a pro I am going to tell you to do it to code which it seems in your case would mean either ovalizing or breaking out. But that is your decision and that of the inspector but if all you can do is 1/4" that is way better than nothing.

 

[fire_man]

It makes me sick to my stomach to think of breaking out 25 feet of virgin clay tiles that never saw even a puff of smoke. What should that cost to break out?

Ovalizing is tempting but I am also concerned about the bend in the smoke chamber.

Thanks for all the tips - this ain't an easy decision.

 

[bholler]

Yeah it sucks we charge an extra $100 to $150 for break out on a job where we are doing the liner also I would think to just break out it would be about $250 but I would have to see the access and weather there are any other flues right next to it to see if it could even be broken out. If there is a flue right next to it there is no way to break out that flue with out damaging the adjacent one.

 

[fire_man]

Darn that's the end of the idea to break out. The reason the smoke chamber has the offset flue is because the oil burner clay liner runs up from the basement through the same chimney.

Otherwise $250 to break out the liner would be bargain compared with the cost to ovalize, extra shipping and the more expensive caps and mating adapters and the cleaning hastles.

Looks like it's ovalize with 1/2" or go with 1/4" insulation.

 

[bholler]

well just because it runs in the same chimney doesn't mean they are to close they really should have a wythe wall between them although most don't. And that is a very rough guess on my part that doesn't mean that that is what a local guy would charge or even that that is what I would charge after looking at it.