Flex liner safe to use after small chimney fire? Pictures

[philip_sallee2]

Hey guys, first time posting on here but wanted to get some feedback.

I am fairly certain we had a small chimney fire on Monday. We have a Vermont Castings Intrepid II stove attached to a Flex King Pro liner that I installed into a masonry chimney/firebox that is lined with clay flu tiles. The chimney is on an exterior wall and is approximately 20', I cleaned it last in January of 2019 after daily use for the previous couple of months but only had 2-3 fires a week till March. This year, we had a cold/wet spell and had a fire going for at least two weeks and really did not think the chimney would be that dirty.

On Monday, the fire was burning down with the damper closed and air shut mostly down, I opened the damper and air intake completely up and went to wash dishes, thinking that the fire was pretty much out. After about 5 minutes, I noticed a strange smell and walked in to find the fire roaring, stove nearing 800 degrees and bright flames rolling up into the chimney from the stove. I closed the damper and air intake and notice a rumble from the chimney, the snout and as much as I could see of the flex liner were glowing red and continued to glow for 2-3 minutes. I went outside and did not notice any flames or sparks coming from the chimney. After a few minutes the noise died out, the heat went away and I let the fire smolder until it was out. I went onto the roof and did not see any obvious signs of damage but did find some splattered creosote next to the rain cap. I also checked the attic and interior walls and inspected from the bottom up, all the interior walls were cool to the touch and no smell of smoke.

Next day I ran a brush down the chimney and inspected the inside of the liner and the outside of the liner to check the flu tiles (phone on a string...). Flu tiles seem fine, the liner is discolored where I assume the fire was concentrated, about 4' from the snout up. Inside of the chimney is cleaner and only concern I have is a couple of small "flaps" on the inside of the liner.

I also pulled the stove out and removed the block off plate at the masonry damper and cleaned the snout and the stove, inspected for cracks and confirmed that about 4' of the liner is discolored and got a closer look at one of the "flaps". The flaps seem to be in places that the liner was bent to flex around the bottom of the masonry chimney.

Sorry for the long description but overall, how well do these stainless flex liners withstand this kind of heat? I checked the documentation that came with it and all it says is that it UL listed to withstand temps of a chimney fire but does not advise if it should be replaced. I do not think I had a full blown chimney fire, I suspect that the fire started in the horizontal section of pipe from the stove, I rarely clean this, and the signs of heat were all in this area, upper portions of the chimney had no discoloration.

Are these flaps a concern? I can feel the inside and outside of the liner and the exterior ply of the liner is solid.

Thanks in advance for any opinions,

 

[EbS-P]

Temper colors might give you an idea of how hot it got. Doesn’t answer your question about safety but from the pics temps stayed below 700f.

 

[bholler]

Hey guys, first time posting on here but wanted to get some feedback.

I am fairly certain we had a small chimney fire on Monday. We have a Vermont Castings Intrepid II stove attached to a Flex King Pro liner that I installed into a masonry chimney/firebox that is lined with clay flu tiles. The chimney is on an exterior wall and is approximately 20', I cleaned it last in January of 2019 after daily use for the previous couple of months but only had 2-3 fires a week till March. This year, we had a cold/wet spell and had a fire going for at least two weeks and really did not think the chimney would be that dirty.

On Monday, the fire was burning down with the damper closed and air shut mostly down, I opened the damper and air intake completely up and went to wash dishes, thinking that the fire was pretty much out. After about 5 minutes, I noticed a strange smell and walked in to find the fire roaring, stove nearing 800 degrees and bright flames rolling up into the chimney from the stove. I closed the damper and air intake and notice a rumble from the chimney, the snout and as much as I could see of the flex liner were glowing red and continued to glow for 2-3 minutes. I went outside and did not notice any flames or sparks coming from the chimney. After a few minutes the noise died out, the heat went away and I let the fire smolder until it was out. I went onto the roof and did not see any obvious signs of damage but did find some splattered creosote next to the rain cap. I also checked the attic and interior walls and inspected from the bottom up, all the interior walls were cool to the touch and no smell of smoke.

Next day I ran a brush down the chimney and inspected the inside of the liner and the outside of the liner to check the flu tiles (phone on a string...). Flu tiles seem fine, the liner is discolored where I assume the fire was concentrated, about 4' from the snout up. Inside of the chimney is cleaner and only concern I have is a couple of small "flaps" on the inside of the liner.

I also pulled the stove out and removed the block off plate at the masonry damper and cleaned the snout and the stove, inspected for cracks and confirmed that about 4' of the liner is discolored and got a closer look at one of the "flaps". The flaps seem to be in places that the liner was bent to flex around the bottom of the masonry chimney.

Sorry for the long description but overall, how well do these stainless flex liners withstand this kind of heat? I checked the documentation that came with it and all it says is that it UL listed to withstand temps of a chimney fire but does not advise if it should be replaced. I do not think I had a full blown chimney fire, I suspect that the fire started in the horizontal section of pipe from the stove, I rarely clean this, and the signs of heat were all in this area, upper portions of the chimney had no discoloration.

Are these flaps a concern? I can feel the inside and outside of the liner and the exterior ply of the liner is solid.

Thanks in advance for any opinions,

 

[bholler]

Hey guys, first time posting on here but wanted to get some feedback.

I am fairly certain we had a small chimney fire on Monday. We have a Vermont Castings Intrepid II stove attached to a Flex King Pro liner that I installed into a masonry chimney/firebox that is lined with clay flu tiles. The chimney is on an exterior wall and is approximately 20', I cleaned it last in January of 2019 after daily use for the previous couple of months but only had 2-3 fires a week till March. This year, we had a cold/wet spell and had a fire going for at least two weeks and really did not think the chimney would be that dirty.

On Monday, the fire was burning down with the damper closed and air shut mostly down, I opened the damper and air intake completely up and went to wash dishes, thinking that the fire was pretty much out. After about 5 minutes, I noticed a strange smell and walked in to find the fire roaring, stove nearing 800 degrees and bright flames rolling up into the chimney from the stove. I closed the damper and air intake and notice a rumble from the chimney, the snout and as much as I could see of the flex liner were glowing red and continued to glow for 2-3 minutes. I went outside and did not notice any flames or sparks coming from the chimney. After a few minutes the noise died out, the heat went away and I let the fire smolder until it was out. I went onto the roof and did not see any obvious signs of damage but did find some splattered creosote next to the rain cap. I also checked the attic and interior walls and inspected from the bottom up, all the interior walls were cool to the touch and no smell of smoke.

Next day I ran a brush down the chimney and inspected the inside of the liner and the outside of the liner to check the flu tiles (phone on a string...). Flu tiles seem fine, the liner is discolored where I assume the fire was concentrated, about 4' from the snout up. Inside of the chimney is cleaner and only concern I have is a couple of small "flaps" on the inside of the liner.

I also pulled the stove out and removed the block off plate at the masonry damper and cleaned the snout and the stove, inspected for cracks and confirmed that about 4' of the liner is discolored and got a closer look at one of the "flaps". The flaps seem to be in places that the liner was bent to flex around the bottom of the masonry chimney.

Sorry for the long description but overall, how well do these stainless flex liners withstand this kind of heat? I checked the documentation that came with it and all it says is that it UL listed to withstand temps of a chimney fire but does not advise if it should be replaced. I do not think I had a full blown chimney fire, I suspect that the fire started in the horizontal section of pipe from the stove, I rarely clean this, and the signs of heat were all in this area, upper portions of the chimney had no discoloration.

Are these flaps a concern? I can feel the inside and outside of the liner and the exterior ply of the liner is solid.

Thanks in advance for any opinions,

There is no where near enough info in those pics for me to tell you if it is safe to use. But I do have a question. Are the pics of the inside of the liner taken from the top or the bottom?

 

[philip_sallee2]

There is no where near enough info in those pics for me to tell you if it is safe to use. But I do have a question. Are the pics of the inside of the liner taken from the top or the bottom?

Thanks, they're taken from the bottom.

 

[bholler]

Thanks, they're taken from the bottom.

In that case your liner was installed upside down and I am sure it has creosote trapped between the plys of the liner. Because of that it is junk regardless of whether it was damaged in the fire or not. And when you replace it don't get the 2ply stuff it is not very durable.

 

[philip_sallee2]

In that case your liner was installed upside down and I am sure it has creosote trapped between the plys of the liner. Because of that it is junk regardless of whether it was damaged in the fire or not. And when you replace it don't get the 2ply stuff it is not very durable.

Thanks for the info, that would make sense. I checked in the documentation that came with it and there was not any mention of which direction of how to install it. How do you know which direction to install it? Also do you have model or brand that you would recommend that is more durable? Is there much safety or longevity benefit to going to straight SS liner instead of the flex? If I remove more of the masonry damper I think I can make it a straight shot to the stove.

Thanks again,

 

[bholler]

Thanks for the info, that would make sense. I checked in the documentation that came with it and there was not any mention of which direction of how to install it. How do you know which direction to install it? Also do you have model or brand that you would recommend that is more durable? Is there much safety or longevity benefit to going to straight SS liner instead of the flex? If I remove more of the masonry damper I think I can make it a straight shot to the stove.

Thanks again,

The liner manufacturer should have been very clear about the proper orientation. I would recommend a heavy wall or midweight liner they are still smooth inside but are much thicker and their construction is much more durable. I don't see any real benefit in rigid liners over heavy flex. And make sure you insulate it.

 

[Ludlow]

The liner manufacturer should have been very clear about the proper orientation. I would recommend a heavy wall or midweight liner they are still smooth inside but are much thicker and their construction is much more durable. I don't see any real benefit in rigid liners over heavy flex. And make sure you insulate it.

Please explain what you see to be saying that the liner was installed upside down, so that we can understand.

 

[bholler]

Please explain what you see to be saying that the liner was installed upside down, so that we can understand.

The unsecured edge of the inner ply is facing up instead of down

 

[Ludlow]

The unsecured edge of the inner ply is facing up instead of down

Can I ask which photo?

 

[bholler]

Can I ask which photo?

The ones showing the inside of the liner.

 

[begreen]

Philip, welcome. I am really glad that you came and asked for advice. And thank bholler for quickly responding.

How was your wood supply late last winter? Poorly seasoned or damp wood can create creosote pretty quickly, especially if the fire is smoldering. If you see smoke coming from the chimney it's not burning cleanly. Do you have a flue thermometer? That can help a lot. Try to keep the flue temp a safe margin over the condensation point of creosote.

 

[begreen]

The ones showing the inside of the liner.

 

[bholler]

View attachment 251831

I can see it in the other one to but that one is really obvious

 

[begreen]

I can see it in the other one to but that one is really obvious

After hundreds of installs, you have a much more trained eye than folks that have only seen one liner. This fishmouth was pretty obvious. Even I could see it!

 

[Ludlow]

The ones showing the inside of the liner.

If we can agree that the pic is of the inside of the liner, and agree with the smoke flow direction, would reversing the liner not allow creo to flow into that seam? Help me understand as I see it.

 

[Ludlow]

Ok, after looking closer, I think I am interpreting the shadow as a void. I think I see it now that I blew up the pic. Good eyes you got!

 

[begreen]

It's the same reason why the crimped seams on single wall pipe face toward the stove. You want the creosote to flow over the seams, not into them. In the illustration the fishmouth seam is acting like a cup to catch the creosote.

 

[Ludlow]

It's the same reason why the crimped seams on single wall pipe face toward the stove. You want the creosote to flow over the seams, not into them. In the illustration the fishmouth seam is acting like a cup to catch the creosote.

View attachment 251833

Yes, as I said I see it now. I was seeing the shadow as a gap when first looking at it. Thanks.

 

[Poindexter]

I was going to say "do whatever bholler says" but since he has already been here, I will instead say, "Do what bholler said."

 

[maple1]

It's the same reason why the crimped seams on single wall pipe face toward the stove. You want the creosote to flow over the seams, not into them. In the illustration the fishmouth seam is acting like a cup to catch the creosote.

View attachment 251833

I haven't got my morning coffee into me yet, that might be part of it - but isn't that what is happening here? Smoke is going up in direction of red arrow, creosote would run down in the direction of the white arrow? Isn't that the same as a stove pipe seam? Or maybe it's the light playing tricks.

 

[bholler]

I haven't got my morning coffee into me yet, that might be part of it - but isn't that what is happening here? Smoke is going up in direction of red arrow, creosote would run down in the direction of the white arrow? Isn't that the same as a stove pipe seam? Or maybe it's the light playing tricks.

When the creosote runns down in the direction of the white arrow it will end up between the 2 plys of the liner. That is the problem

 

[Ludlow]

I haven't got my morning coffee into me yet, that might be part of it - but isn't that what is happening here? Smoke is going up in direction of red arrow, creosote would run down in the direction of the white arrow? Isn't that the same as a stove pipe seam? Or maybe it's the light playing tricks.

Your eyes are seeing it like mine did. That black area isnt the gap. It is the shadow of the camera flash playing tricks. Bholler is right.

 

[Ludlow]

Ok. Everytime I look at it I see it different. Here is a larger look.