Getting my liner past the fireplace damper

[SCNewbie]

New to the site...

I have a new to me Jotul F400 Castine I’d like to install in an existing fireplace. The fireplace has a 33” x 5.5” damper. Above that is a masonry smoke shelf that’s a hair over 6” deep and gradually widens to a 12” x 12” clay lined chimney flue. The manual says I can do a direct connect and exhaust at the bottom of the clay lined section… But all of the local shops tell me to line the chimney for ease of cleaning, better draft, and a host of other reasons.

A few questions on this intstall:

Can I simply ovalize the bottom 4 feet of liner? If so what do I use to connect the oval liner back to my 6” round stove pipe below the damper? Or should I remove the damper/brick to stay round all the way to the top of the chimney? Ideas? Thanks!

 

[bholler]

New to the site...

I have a new to me Jotul F400 Castine I’d like to install in an existing fireplace. The fireplace has a 33” x 5.5” damper. Above that is a masonry smoke shelf that’s a hair over 6” deep and gradually widens to a 12” x 12” clay lined chimney flue. The manual says I can do a direct connect and exhaust at the bottom of the clay lined section… But all of the local shops tell me to line the chimney for ease of cleaning, better draft, and a host of other reasons.

A few questions on this intstall:

Can I simply ovalize the bottom 4 feet of liner? If so what do I use to connect the oval liner back to my 6” round stove pipe below the damper? Or should I remove the damper/brick to stay round all the way to the top of the chimney? Ideas? Thanks!

Keep it round it will work allot better. And the local shops are right you don't want a direct connect and your clay is to large anyway. The clay can be no more than 3x the volume of the stove outlet. But yours is much larger than that. You will also want the liner to be insulated and you will want a blockoff plate.

 

[SCNewbie]

Thanks bholler, good info.

I guess my biggest concern is spiking cost. Especially if I have to start removing a lot of masonry.

My smoke shelf is pretty narrow, just over 6 inches. If I had ovalize the bottom 36 inches of my liner, and I mean only down to about 5 1/2 inches, how critical is that?

 

[bholler]

Thanks bholler, good info.

I guess my biggest concern is spiking cost. Especially if I have to start removing a lot of masonry.

My smoke shelf is pretty narrow, just over 6 inches. If I had ovalize the bottom 36 inches of my liner, and I mean only down to about 5 1/2 inches, how critical is that?

If there is no other option it can be ovalized but it should be a last resort. I have yet to see one that took me more than 30 mins or so to open up

 

[SCNewbie]

Bholler - I know a guy who’d send you on a short paid vacation to SC... just sayin.

 

[mstoelton]

Don't ovalize, it will make your cleaning job much harder. The damper can likely be removed and the masonry modified in less than an hour. You can do it yourself with a 4.5 inch grinder ($15 at harbor freight) a cut-off wheel ($5 harbor freight) and a rental demo hammer from home depot ($40-$50). Once you have the demo hammer the masonry removal will be really quick. I did my own and it was like yours (about 1/2 to one inch more and it would have cleared). It took me longer to drive the 15 minutes (round trip) to home depot and get the hammer drill than the actual work took to complete.

 

[SCNewbie]

Don't ovalize, it will make your cleaning job much harder. The damper can likely be removed and the masonry modified in less than an hour. You can do it yourself with a 4.5 inch grinder ($15 at harbor freight) a cut-off wheel ($5 harbor freight) and a rental demo hammer from home depot ($40-$50). Once you have the demo hammer the masonry removal will be really quick. I did my own and it was like yours (about 1/2 to one inch more and it would have cleared). It took me longer to drive the 15 minutes (round trip) to home depot and get the hammer drill than the actual work took to complete.

Thanks for the encouragement… I actually have most of the tools needed, I just don’t have a good understanding of which bricks I can remove and which ones I shouldn’t. I suppose the idea is to remove only as much as you need to. How did you seal up the area on either side of your liner once you are complete? Block off plate? Rock wool? Thanks.

 

[mstoelton]

• You will need a block-off plate. It can be made in one or two pieces, and should be installed while installing your insulated liner. You can install rock wool on top of the block-off plate that will add to your heat retention. Also be sure to add a top plate to your install that is sealed with silicone. I also suggest that you install a top plate and screen that has a hinged cover for the ease of cleaning your liner. These cost a bit more but are well worth the extra cost if you sweep yourself.
• As far as what to remove, you will want to remove only perhaps 1-3 bricks to be modified. I created my one piece block-off plate with fairly heavy gauge steel (I think 10 Gauge - too hard to work ) but the directions on this site will specify lighter steel which is fine. Your block-off plate can be secured in place with tapcons that are drilled into the mortar between bricks, and sealed with high temp (red) silicone. The block-off can be wedged above the tapcons and sealed in place prior to your actual stove install.

 

[SCNewbie]

• You will need a block-off plate. It can be made in one or two pieces, and should be installed while installing your insulated liner. You can install rock wool on top of the block-off plate that will add to your heat retention. Also be sure to add a top plate to your install that is sealed with silicone. I also suggest that you install a top plate and screen that has a hinged cover for the ease of cleaning your liner. These cost a bit more but are well worth the extra cost if you sweep yourself.
• As far as what to remove, you will want to remove only perhaps 1-3 bricks to be modified. I created my one piece block-off plate with fairly heavy gauge steel (I think 10 Gauge - too hard to work ) but the directions on this site will specify lighter steel which is fine. Your block-off plate can be secured in place with tapcons that are drilled into the mortar between bricks, and sealed with high temp (red) silicone. The block-off can be wedged above the tapcons and sealed in place prior to your actual stove install.

Mstoelton... thanks for the detailed reply. I have a little down time next week... guess I’ll tackle this one step at a time.

 

[Mike.O]

I installed mine a few months ago and this is what I came up with.... Forgot to take pics of install, but marked up a pic off google to illustrate...

My approach was to reuse the damper as my block off plate. I did this by cutting a hole for my liner in it. The damper was smaller than the liner, so I left about 3/4" of meat on the damper and then cut a +/- 7" diameter circle in the damper. I had approximately 2" of the circle that was "off" the damper so I removed the damper frame in that location and chipped about 1-1/2" of masonry out. I now had a 7" hole between the damper and the chipped out masonry.

I jockeyed the damper up and rested it up in the chimney, so it could drop right in after the liner was put in. I dropped the liner down and got it though the hole. I dropped the damper with the cut out around the liner and it fit perfectly, with 1/4" clearance. There were a few larger holes of a few inches on the side where I chipped the masonry. I had a little insulation left from the liner kit, so a few small hand fulls and it was sealed up.

I felt this was the easiest solution as the damper plate was already fitted to the opening. Trying to create a new block off plate would have been much more challenging than cutting a hole in the old plate. It was tricky to cut the circle with an angle grinder in the 1/4 plate, but it's manageable.

Just figured I'd share.

 

[SCNewbie]

I installed mine a few months ago and this is what I came up with.... Forgot to take pics of install, but marked up a pic off google to illustrate...

My approach was to reuse the damper as my block off plate. I did this by cutting a hole for my liner in it. The damper was smaller than the liner, so I left about 3/4" of meat on the damper and then cut a +/- 7" diameter circle in the damper. I had approximately 2" of the circle that was "off" the damper so I removed the damper frame in that location and chipped about 1-1/2" of masonry out. I now had a 7" hole between the damper and the chipped out masonry.

I jockeyed the damper up and rested it up in the chimney, so it could drop right in after the liner was put in. I dropped the liner down and got it though the hole. I dropped the damper with the cut out around the liner and it fit perfectly, with 1/4" clearance. There were a few larger holes of a few inches on the side where I chipped the masonry. I had a little insulation left from the liner kit, so a few small hand fulls and it was sealed up.

I felt this was the easiest solution as the damper plate was already fitted to the opening. Trying to create a new block off plate would have been much more challenging than cutting a hole in the old plate. It was tricky to cut the circle with an angle grinder in the 1/4 plate, but it's manageable.

Just figured I'd share.
View attachment 235977

Mike.O - I like the idea of using the damper as the block off plate. Very ingenious.

The obstacle to have is the 6-1/2” smoke shelf. It extends upwards a good two feet. Not enough room to work up there. So I’m likely going to insulate my liner only down to the smoke shelf, and then I can stay round all the way down.

Thanks for the reply/diagram. That’s helpful.

 

[lml999]

I guess my biggest concern is spiking cost. Especially if I have to start removing a lot of masonry.

Your biggest concern should be a chimney fire. Take the extra time (and money, if necessary) to plan and build a safe installation. If you're not sure what you're doing (based on experience), hire a professional. And watch them closely...

 

[SCNewbie]

Your biggest concern should be a chimney fire. Take the extra time (and money, if necessary) to plan and build a safe installation. If you're not sure what you're doing (based on experience), hire a professional. And watch them closely...

I had a professional sweep inspect my existing masonry chimney... clean bill of health, it wasn’t even worth running a brush through it. Having been constructed for a wood burning fireplace, it’s the best starting point possible... minus the constricted area above the damper.

With enough time, the right tools, and the expertise; anything is do-able. Plus I enjoy the feeling of accomplishment after succeeding at a difficult task.

That said... Warning heeded... safety first! Thanks.

 

[EbS-P]

Hi
I had a professional install mine. He removed the entire damper assembly. It wasn’t a strait shot down into the stove so he broke out the top center firebrick and reset it an inch to the back so the single piece of insulated flex liner dropped right on the to stove. I will be installing a blockoff plate. It would have been easier at time of install. Hope that is helpful. I can post more pictures if it would be helpful.

Evan