Chimney liner concerns on our setup?

[RJ in PA]

Good evening,

I was curious as to everyone's thoughts on the following situation:

We currently have a ~30 foot cinderblock + 8"x12.5" tile chimney (in interior of the home), built in the 1980s.
It has quite good draft, causing strong burns on our old kodiak wood stove insert.

Several years ago, a local stove specialist instialled what I believe to be a 6x9" or 4x9" oval corrugated flex steel 316ti liner from the top (with a raincap) to the stove. He had to push and pull it down pretty hard several times
In order to fit this liner in the chimney which has two bends, he chipped away and broke up parts of the old tile ( although not much). I think the chimney is in good shape otherwise.

Should I be concerned about the safety of this?
I do not think we will be able to insulate the pipe due to several reasons, or be able to fit in a insulated flex liner as well into the bendy narrow chimney.

I understand the code says that 2 inches of clearance around the chimney is required, but this is not possible for us in a older farmhouse.

Do people think this would be a safe setup? Would it be better or a good practice for me to just work along with this setup and clean out our chimney every 1-2 weeks during the burning months? I probably will clean from the bottom-up due to the roof steepness and height of our old farmhouse.

Or should I go the more laborious and expensive route of taking out the new liner, and trying to fit a insulated flex liner down the chimney?? I have a hard time imagining this being possible.

Thank you for your help and advice, I appreciate it!

 

[stoveliker]

I just note that the proposed solution (frequent cleaning) doesn't mitigate the problem of having combustibles within the 2" clearance distance around the chimney.

Pyrolysis happens slowly, and may not be seen until wood combusts suddenly because its ignition temperature has decreased enough.

 

[Ryan_C]

The bigger question is whether the liner is properly sized, continuous, and in good condition. If it's drafting well and you're not having creosote problems, cleaning every week or two shouldn't be necessary unless you're burning marginal wood.

As for insulation, it's definitely preferred, but if an insulated liner simply won't fit, I'd talk to a certified chimney sweep before tearing everything apart. There are plenty of older chimneys out there with uninsulated stainless liners that have operated safely for years, but I'd want someone to verify that your particular installation meets the liner listing and is appropriate for your chimney rather than assuming more frequent cleaning makes up for it.

 

[bholler]

Where are you in central pa?

 

[RJ in PA]

I just note that the proposed solution (frequent cleaning) doesn't mitigate the problem of having combustibles within the 2" clearance distance around the chimney.

Pyrolysis happens slowly, and may not be seen until wood combusts suddenly because its ignition temperature has decreased enough.

Hello @stoveliker @Ryan_C @bholler ,

Thank you for your responses and help, I really appreciate it!

BHoller, We are located in Perry County PA, not far from Newport. I see that your profile mentions you are from central PA also!

Stoveliker, thanks for bringing the issue of pyrolysis to my attention. There is certainly not 2 inches of clearance around the 1980s built cinderblock and tile chimney, unfortunately. Actually, I do notice that some log parts of the home come within 1/2 inch of the cinderblock at one place.

Ryan_C, I believe the liner size installed is a 6"x9" oval liner. It was installed by a man who has a stove shop, several years ago.

Unfortunately, since we were busy in the process of moving and setting up our farm here in central PA, I did not do the research I probably should have done (which I am trying to do now) to ensure the liner size/installation methods were ok and safe.
At the chimney top, the solid piece of pipe which connects to the oval flex measures 6" x 9" oval. It is a new continuous liner made from 316ti steel, according to the installer who brought the liner on his truck.
Our chimney is between 25 and 30 feet long, and drafts quite well. It has 8"x12.5" clay tile.

During the installation process, I remember the installer used a breaking ball drill attachment to break up a section of tile in the chimney (which was previously in quite good shape and barely used since the 1980s), in order to force the oval liner around a sharp bend located between the 1st and 2nd levels of our home. They forced it mostly from the top-down, and only pulled it down the last few feet. However, I do remember it did get snagged several times when they forced it down.

The new stove we plan to hook up to the bottom is a SBI wood stove with a 6 inch vent. I understand now that the liner is oversized for this chimney.
I am concerned that the oversized liner may be in direct contact with the cinderblock chimney now (due to the clay tiles being broken up at one section), and potentially may cause issues with overheating in that one section.
When discussing the liner with the installer, he told me that the oversized liner would be no issue for the SBI wood stove, and would draft ok. However, since I do not have much experience with chimneys, I am not sure.

Although I could always clean the chimney more frequently (if creosote builds up) to reduce its risk of chimney fires, I am now wondering if pyrolysis or combustible clearance with a oversized, un-insulated liner in contact with the tile/cinderblock is more of a concern (due to radiant heat).
Perhaps taking out this liner, and installing a smaller, properly sized oval liner would be a better option (although costly)? And then maybe pour a removable vermiculite mix such as Everguard Pour Down Chimney Insulation Mix? But then I wonder how the pour in insulation would be able to be centered equally all around the liner, especially around the bends.

Thank you again for your help! Since I and my family mostly do small scale farming here in PA, I appreciate your chimney and stove help greatly!
Russ J

 

[bholler]

Hello @stoveliker @Ryan_C @bholler ,

Thank you for your responses and help, I really appreciate it!

BHoller, We are located in Perry County PA, not far from Newport. I see that your profile mentions you are from central PA also!

Stoveliker, thanks for bringing the issue of pyrolysis to my attention. There is certainly not 2 inches of clearance around the 1980s built cinderblock and tile chimney, unfortunately. Actually, I do notice that some log parts of the home come within 1/2 inch of the cinderblock at one place.

Ryan_C, I believe the liner size installed is a 6"x9" oval liner. It was installed by a man who has a stove shop, several years ago.

Unfortunately, since we were busy in the process of moving and setting up our farm here in central PA, I did not do the research I probably should have done (which I am trying to do now) to ensure the liner size/installation methods were ok and safe.
At the chimney top, the solid piece of pipe which connects to the oval flex measures 6" x 9" oval. It is a new continuous liner made from 316ti steel, according to the installer who brought the liner on his truck.
Our chimney is between 25 and 30 feet long, and drafts quite well. It has 8"x12.5" clay tile.

During the installation process, I remember the installer used a breaking ball drill attachment to break up a section of tile in the chimney (which was previously in quite good shape and barely used since the 1980s), in order to force the oval liner around a sharp bend located between the 1st and 2nd levels of our home. They forced it mostly from the top-down, and only pulled it down the last few feet. However, I do remember it did get snagged several times when they forced it down.

The new stove we plan to hook up to the bottom is a SBI wood stove with a 6 inch vent. I understand now that the liner is oversized for this chimney.
I am concerned that the oversized liner may be in direct contact with the cinderblock chimney now (due to the clay tiles being broken up at one section), and potentially may cause issues with overheating in that one section.
When discussing the liner with the installer, he told me that the oversized liner would be no issue for the SBI wood stove, and would draft ok. However, since I do not have much experience with chimneys, I am not sure.

Although I could always clean the chimney more frequently (if creosote builds up) to reduce its risk of chimney fires, I am now wondering if pyrolysis or combustible clearance with a oversized, un-insulated liner in contact with the tile/cinderblock is more of a concern (due to radiant heat).
Perhaps taking out this liner, and installing a smaller, properly sized oval liner would be a better option (although costly)? And then maybe pour a removable vermiculite mix such as Everguard Pour Down Chimney Insulation Mix? But then I wonder how the pour in insulation would be able to be centered equally all around the liner, especially around the bends.

Thank you again for your help! Since I and my family mostly do small scale farming here in PA, I appreciate your chimney and stove help greatly!
Russ J

You can always call us. Pm me if you want. You are within our service area

 

[RJ in PA]

You can always call us. Pm me if you want. You are within our service area

Thank you Bholler, I will do that! I do appreciate the help/advice of those who have experience, especially when it comes to chimney safety or concerns.
Russ

 

[RJ in PA]

Any other thoughts or ideas on this situation? I surely appreciate the help/advice!
Many thanks,
Russ J

 

[EbS-P]

Any time I would install a new appliance I would run a camera up or down the liner myself. I any concerns I’d would get an opinion from hearth.com members.

I can tell you anything on 30’ will really draft, probably above the specs. So plan now how you will install a damper or other restriction.

 

[RJ in PA]

Any time I would install a new appliance I would run a camera up or down the liner myself. I any concerns I’d would get an opinion from hearth.com members.

I can tell you anything on 30’ will really draft, probably above the specs. So plan now how you will install a damper or other restriction.

Thank you for your advice, I appreciate it.
I was planning to put a damper in the stove pipe section that is horizontal, between the elbow of the stove vent and the elbow connecting to the liner, so hopefully that would work well.

I was considering pouring down everguard insulation mix from the chimney top, but I am not sure if I should or even can due to the limited clearance around the 7 inch round equivalent (according to the installer) in our 8x12.5 clay liner which has a few sharp bends in the nearly 30' chimney.