Positive connection to existing flue or liner?

[thurstmw]

My understanding is that liner is always the answer to this, and that was my plan... but I have a bit of a problem.

I just bought a Jotul C350 fireplace insert which has a 6" flue. I did not first check the size of my fireplace's flue. It is insulated 11x6" clay tile.

It seems like it will be impossible to squeeze a 6" liner down that so my options for a liner would be to have an oval one made (like 3x the price) or use an undersized 5" liner which I imagine would still be a tight fit and is probably a terrible idea?

The manual says a positive connection is acceptable on external chimneys as long as the flue is smaller than 9x8". I assume 11x6" would be OK because the area is 66" compared to 72" for 9x8". Am I correct about this?

If I do this can I just use black stove pipe to make the connection? How far up the flue would it need to go? Would I need to make the block off plate myself or is there a way to buy those?

Any better ideas would be very much appreciated.

Thanks

 

[bholler]

If I do this can I just use black stove pipe to make the connection? How far up the flue would it need to go? Would I need to make the block off plate myself or is there a way to buy those?

Technically you could do it. It would have to be done out of stainless and you would have to figure out how to attach it to your existing liner. That is where the problem comes in I have yet to see anyway to really attach a new section of liner to an existing fireplace liner. So while it may technically be possible in actuality it really is not. And without that positive connection to your fireplace liner you will have lots of dilution air getting in there which will cause poor draft and excess creosote buildup. I would recommend an ovalized liner. Or possibly a 5.5"

 

[thurstmw]

Technically you could do it. It would have to be done out of stainless and you would have to figure out how to attach it to your existing liner. That is where the problem comes in I have yet to see anyway to really attach a new section of liner to an existing fireplace liner. So while it may technically be possible in actuality it really is not. And without that positive connection to your fireplace liner you will have lots of dilution air getting in there which will cause poor draft and excess creosote buildup. I would recommend an ovalized liner. Or possibly a 5.5"

You think I could get a 5.5 down the chimney? I sifted through a lot of threads here before posting and it seemed like even an 8x8 flue was tight for a 6" liner. If I did that would I need a special connector to step it down from 6-5.5?

 

[bholler]

You think I could get a 5.5 down the chimney? I sifted through a lot of threads here before posting and it seemed like even an 8x8 flue was tight for a 6" liner. If I did that would I need a special connector to step it down from 6-5.5?

What type of liner do you have you said it was an insulated 6x11 so I assumed it was stainless which is much easier to get a liner into than clay. And because it is insulated there is no need for additional insulation. I am not there looking at it so I need more info to know what is best. And btw an 8x8 clay is 8x8 outside not inside.

 

[thurstmw]

What type of liner do you have you said it was an insulated 6x11 so I assumed it was stainless which is much easier to get a liner into than clay. And because it is insulated there is no need for additional insulation. I am not there looking at it so I need more info to know what is best. And btw an 8x8 clay is 8x8 outside not inside.

It's clay. The 6x11 though are interior measurements made from the top of the flue.

 

[bholler]

It's clay. The 6x11 though are interior measurements made from the top of the flue.

Oh so is it insulated clay??? that is different. If it is actually insulated correctly you could get an oval in there no problem but if it is actually 6" wide clay I really doubt you will get a 5.5" in there. And if you need insulation it might be tight even ovalized you may need to remove the liners.

 

[thurstmw]

Oh so is it insulated clay??? that is different. If it is actually insulated correctly you could get an oval in there no problem but if it is actually 6" wide clay I really doubt you will get a 5.5" in there. And if you need insulation it might be tight even ovalized you may need to remove the liners.

It may not be insulated... is it abnormal for it to be?

I thought that was the whole idea of the clay tiles within the brick but I am very new to this.

Removing them would require smashing them apart and pulling them out?

 

[bholler]

It may not be insulated... is it abnormal for it to be?

yes very abnormal

I thought that was the whole idea of the clay tiles within the brick but I am very new to this.

Nope very little insulation value there which is why with masonry like that you still need clearance to combustibles from the outside of the chimney to any combustible material. 1" for an external chimney 2" for internal.

Removing them would require smashing them apart and pulling them out?

Yep you use a tile breaker that spins in there and you shovel the peices out the bottom. I like to try to avoid doing it on fireplaces but if your liner is that small there may not be much option.

 

[thurstmw]

Ok, that's disappointing to hear.

So what is behind the clay? Brick? Just a void? The external dimensions are like 36x24. I just figured the flue was so much smaller because it was insulated in between.

 

[bholler]

So what is behind the clay? Brick? Just a void? The external dimensions are like 36x24. I just figured the flue was so much smaller because it was insulated in between.

it is occasionally open space but usually it is back filled with brick block ect. But you may also have a block core with a brick layer over top of it Like I said without being there it is hard to say. But I can tell you that we break out between 30 and 50 a year and in the 40 years my father has been dong it he has only seen a few insulated in my 9 years I have seen one.

 

[thurstmw]

it is occasionally open space but usually it is back filled with brick block ect. But you may also have a block core with a brick layer over top of it Like I said without being there it is hard to say. But I can tell you that we break out between 30 and 50 a year and in the 40 years my father has been dong it he has only seen a few insulated in my 9 years I have seen one.

Ok thanks for all your help and your quick responses. It has really helped me understand the whole deal a bit better.

I have two more questions if it's not too much.

Is renting a tile breaker from rockford a reasonable way to go, or would you recommend something else? https://www.rockfordchimneysupply.com/tile-breaker-and-rods-kit-rental.php

And off the topic of the flue, my stove came with the bottom trim piece, but not risers to go under it. Can I just stick a couple fire bricks under it to hold it?

 

[double-d]

The steel rods and tile breaker appear to be from ProKleen, or Rutland, both good companies. As bholler mentioned, the clay tiles usually break up easily, just don't beat on the structure behind the bricks.
If you are going to do it, it appears that they pay for the shipping both ways, and it's cheaper than buying them, unless your looking to start your own tile removing business.

 

[bholler]

yes those tools will work fine it is pretty much what we use but be careful not only to not damage the chimney structure but also not to damage yourself. You will need to use a pretty powerfull drill to run that breaker and it can hurt you or throw you off the roof if the breaker binds up. I would get a quote for removing the tiles if I were you it can go really easily we get many done in under an hour. But we also have ones that take multiple days.

 

[Squisher]

You could check out the M and G duraliner oval insulated is 4 3/4" x 7 3/4". You can google up their catalogs pretty easily and see if it might work for you.