Liner pic, I am stumped and discouraged

[brian89gp]

Report from the sweep:

It is not a chimney fire. The chimney cap shows no evidence of excessive heat and the very top of the flue and the cap itself only had ash build up, zero creosote anywhere. The rest of the installation checks out and there is nothing that needs to be addressed. The damage to the bottom of the liner was caused either by one or more huge over-fire events or a continual lower heat over fire (me burning hot 24x7). It is impossible to tell if the strong draft was actually sucking part of the secondary burn up the liner and/or it was just the heat itself from the secondary burn over-temping the liner, but the damage was directly caused by heat from the firebox in some manner.

Recommendations:
1. Flue damper
2. The smaller ID liner idea holds weight in that it limits total volume of flow, though whether it can still flow enough for a serious over-fire is only a guess.
3. Use the standard type of corrugated liner with the idea that the smooth wall is newer and maybe they haven't gotten all the bugs worked out yet and it will draft a little less then the smooth one. Said when installing gas appliances that they are required to upsize the liner one size if using corrugated since it flows less then smooth and they use the double wall smooth flex for gas appliances specifically because of that.
4. Either figure out how to fully dampen down the stove or get a different one

A stove that can be fully closed down while on a 40' flue being the key, the rest are more preventative measures to help reduce the chances of it happening again.

 

[STOVEGUY11]

Most Stoves that I have seen, state 35' as the max for the chimney height. I don't know if that is standard, or if it varies stove to stove.

 

[rdust]

A stove that can be fully closed down while on a 40' flue being the key, the rest are more preventative measures to help reduce the chances of it happening again.

Can you modify your secondary air supply on your current stove?

A cat stove will do about the best for getting close to "fully" closed.

With my BK I can knock the flame out of any fire with the turn of the knob no matter how active the primary fire is. After the primary fire gets knocked out a secondary burn in the top can happen but that doesn't last long. With the BK they have a hole in the air flapper that feeds the stove when it's on low, worst case you could make the hole smaller if needed but I think you'd be ok with it as installed from the factory.

 

[brian89gp]

Stoveguy, I had looked through the documentation and called Buck about it and they have no published upper limit. They suggested that if I had a draft issue that I should put a damper on it.

rdust, a cat stove would be ideal for me. Less fussing about for me and a lot easier on my girlfriend to load, only problem is that a good portion of the cat stoves are 8" liner and the brick chimney is only 7.5" (that 6" insulated liner was a tight squeeze). The BK Princess insert has my eye but its hard to justify the cost seeing as I got the Buck 85 for like $600 in very good condition. Slightly warped now, but the welds all checked out so its still good to burn.

On the Buck 85 both the primary and secondary air pull from the same air intakes. While I have the stove out I'll probably poke around and at the very least modify the intakes so that they fully close. I'll also look to see if I cant separate out the secondary air into its own intake.

I will say one thing though, these Buck stoves are tough. I mean it survived what I put it through with only a warped top plate and I was not being nice.

 

[alex johnson]

New liner last fall, 6" stainless smooth bore flex with 1/2" insulation. Went through about 5.5 cords of dry wood. Go to clean my chimney and I see this and I am just flabbergasted. It looks like it has been partially melted and all the seams are seperating. That is insulation you see in the seam that has fully seperated up the pipe a little bit. How does this happen? Did I somehow manage to put it in upside down?

Pic is from the stove side.

Zero black creosote anywhere. Just white ash and this brown fluffy stuff

I heard something one time that made sense after I thought about it. All chimney's accumulate creosote no matter how dry your wood may be. I am sure I will hear about it, I heard that about every two weeks you want to have mini creosote fires. within your chimney. I have learned and it works, I flush the flue with fire, get my stove up to operating temps. I get the flue temp up around 600 get it there and hold it, then put dry, dry, dry wood in and let it eat, this will send fire up through the liner from the stove, this fire acts as a broom. When your letting the pipe warm up and holding it there it will start to cook the creosote. It will start to pop off the liner, and this fire that is flying by catches the creosote on fire, and burns it off and the movement of the fire will clean it. When I read the back of the tubs of creosote buster, it said you need to get your stove hot, and keep it there for a specific time. That stuff really don't help it's the high heat that kinda burns it off. I used to use a daka furnace to heat my house. I had it in a little building that wood blow air into the house. Well one night I smelled something, went out to the shed and I could see the chimney rising just above the building and it was red, with a little fire shooting out the flue. I built the set up just in case this happened, I shut all the air off to the stove, and let it burn itself out. It went on for about 45 minutes and all done. I let it go out, the next day I went and pulled the bottom cleanout door off the chimney, and there was just a little bit of flyash on the cap. Looked up the flue, it was the cleanest I have ever seen it. I left most of my flue exposed to the elements. It is made out of a full piece of 6" 1/8 wall, little smaller than that. works awesome and only cost me about 50 bucks for 20'. With your setup, I am pretty confident it happened like this. You say you have 40 feet of flue, hell of a draft. that can be a good thing. I am pretty sure that, with 40 feet of flue, the uppermost section probably had more buildup, then closer to the stove. I bet it plugged up slowly, from the top down. Did you ever notice, that it didn't draft regulary, then all of a sudden one day it had lungs of a hurricane? It plugged up finally one day enough, that the heat accumulated and caught fire or fire made it up. When you have a chimney fire within a liner, that is within a brick chimney. You contained all that heat, which is alot inside that liner. I could imagine after it was done the brick was super hot. Your liner did what it was designed to do. the reason ther was just a little white ash on the baffle. Is that you burnt all the creosote up to nothing, and with just the movement of the heat rising, carried the ash out of the flue. I watched it happen to mine. same thing, little different set up. I personally wood rather have a steel pipe like the ones that I use, then a stainless liner. My pipe is solid, not one seam that could deform and seperate. Stainless liners, way to many places for seperation. These liners are designed to withstand high heat for a short period of time, not for 20 or 45 minutes in my situation. I flush my flue out with fire, Bi-weekly. it stays clean!! it makes sense, good luck

 

[rdust]

I flush my flue out with fire, Bi-weekly. it stays clean!! it makes sense, good luck

Good Luck to you!

 

[begreen]

Good summary. I think 5" liner with a key damper if needed will tame the beast.