Holy Creosote, Batman!

[delagem]

I installed a Hearthstone 3 wood stove last fall. These are from the 1980s, this model is the electronic model, which "should" have a thermostat that controls the air inlet.

591F26C6-CC20-441B-BA84-503D609F23CD by michael delage, on Flickr

As the seller didn't have the air inlet, I used the simple bypass lever on the side. This is that lever, in the open position:

IMG_3496 by michael delage, on Flickr

Old house, brick chimneys, I installed a 6" double wall smooth interior flex pipe. It's about 27' long.

Image-1 by michael delage, on Flickr

Ok, now for the part that the title of this thread is about! This has only been installed 4 months ago. I burned about 4 face cord of wood over the past 4 months. Stove started smoking very badly. I went up on the roof, to see this:

IMG_3474 by michael delage, on Flickr

Pulled the cap, it wasn't pretty:

IMG_3475 by michael delage, on Flickr

It had actually completely closed itself off on the last fire!

IMG_3476 by michael delage, on Flickr

So I know, first thought is, wet wood. Nope. This stuff is great. Seasoned, stored under cover, well-ventilated.

IMG_3493 by michael delage, on Flickr

So, what's going on here? My guess is that little air inlet that Hearthstone provided isn't letting enough air in. I know they offered a spindraft retrofit kit for the electronic models many years ago. Those aren't available anymore, but I'm thinking I'll use a few of these Schrader Air Control knobs in the ash door to allow more air.

70225901504__84FAA794-FEE8-445D-8057-345D3313AD65 by michael delage, on Flickr

Anyone have any ideas what's going on here?

 

[bholler]

I installed a Hearthstone 3 wood stove last fall. These are from the 1980s, this model is the electronic model, which "should" have a thermostat that controls the air inlet.

591F26C6-CC20-441B-BA84-503D609F23CD by michael delage, on Flickr

As the seller didn't have the air inlet, I used the simple bypass lever on the side. This is that lever, in the open position:

IMG_3496 by michael delage, on Flickr

Old house, brick chimneys, I installed a 6" double wall smooth interior flex pipe. It's about 27' long.

Image-1 by michael delage, on Flickr

Ok, now for the part that the title of this thread is about! This has only been installed 4 months ago. I burned about 4 face cord of wood over the past 4 months. Stove started smoking very badly. I went up on the roof, to see this:

IMG_3474 by michael delage, on Flickr

Pulled the cap, it wasn't pretty:

IMG_3475 by michael delage, on Flickr

It had actually completely closed itself off on the last fire!

IMG_3476 by michael delage, on Flickr

So I know, first thought is, wet wood. Nope. This stuff is great. Seasoned, stored under cover, well-ventilated.

IMG_3493 by michael delage, on Flickr

So, what's going on here? My guess is that little air inlet that Hearthstone provided isn't letting enough air in. I know they offered a spindraft retrofit kit for the electronic models many years ago. Those aren't available anymore, but I'm thinking I'll use a few of these Schrader Air Control knobs in the ash door to allow more air.

70225901504__84FAA794-FEE8-445D-8057-345D3313AD65 by michael delage, on Flickr

Anyone have any ideas what's going on here?

What moisture content is your wood at?

What temps are you running at?

Is the liner insulated?

 

[delagem]

What moisture content is your wood at?

What temps are you running at?

Is the liner insulated

Thank you for the reply.

I don't have a moisture content meter. In 50 years of using wood stoves, I've never needed one. (I knew someone would ask moisture content!). This wood is good.

Temps, unknown. Sorry, that's on me. The magnetic flue thermometers wouldn't stick the the SS pipe, so I never ran one.

The liner is double-walled SS, with a smooth interior. Insulation? Dunno. Doubt it, other than air between the double walls.



Interestingly, the creosote was only really bad on the 3' of pipe that cleared the chimney. Obviously, even though the pipe is double-walled, it's getting cold enough to have an effect where it clears the chimney.

A friend suggested cutting the pipe flush with the top of the chimney. I think that's a bad idea. It should stand proud of the nearby obstructions (there are 5 flues in this chimney, all the others are simple fireplaces with caps).

My thought was, maybe put a piece of SS pipe around the 3' of liner as it clears the chimney? Add insulation?



I still think the main issue is the lack of air at the stove. There's nothing wrong with this chimney liner that I can see. Which leaves the stove as the primary issue.

 

[bholler]

Ok without any data on how you are running things I can't give much input other than the liner should be insulated. It will help. Maintain temps much better. And a liner should absolutely never extend out of a chimney that far to do that you need a class a extension with proper adapter etc. Also be careful with that double wall liner they are very delicate

 

[bholler]

And yes the wood does look decent but that doesn't mean it's below 20% like it should be. How long has it been cut split and covered?

 

[delagem]

Ok without any data on how you are running things I can't give much input other than the liner should be insulated. It will help. Maintain temps much better. And a liner should absolutely never extend out of a chimney that far to do that you need a class a extension with proper adapter etc. Also be careful with that double wall liner they are very delicate

Good to know, thank you. How would you insulate a production-made product like this liner?

I'll look into chimney extensions.

And yes the wood does look decent but that doesn't mean it's below 20% like it should be. How long has it been cut split and covered?

Bought from a pro, I really don't know the history of the wood. It was delivered last fall. Covered since delivered. As the Hearthstone 3 is such a small stove, I've had to split every single piece 2-3 more times each, just for fitment issues.

This wood isn't a problem in the other 6 chimneys I have. They are all fireplaces, however. This is the only wood stove. And the only one with an issue.

 

[bholler]

Good to know, thank you. How would you insulate a production-made product like this liner?

With the insulation kit specified for use with that liner when it's used for a solid fuel burning appliance

 

[xman23]

A lot not to good. Was it spotless clean before you started? Wet wood and burning cold will do that. Chimney is just getting to cold.

 

[ct_administrator]

I only had glazed creosote when I ran my non-EPA stove at low temps. Was mostly in the same area as yours, near the top of my chimney. Glazed creosote is the most dangerous type of buildup.

Do you use any products to prevent this issue? Creosote powder that you put over your coals? or other solutions?

What does the stack look like when you're running the stove? Lots of smoke?

 

[BigJ273]

I’m no expert, but clearly that extended part of the liner is cooling way too much due to its exposure. I don’t think I’ve ever seen that done before. I have seen clay tiles extended above the crown, but not just a bare liner by itself. It doesn’t stand a chance to keep temps high enough out in the elements like that. Just my opinion

 

[armanidog]

Bholler, how much will it cost to clean the flue using the PCR poultice creosote remover?

It may be cheaper in the long run to replace the flue and use a flue with the insulation already built into a double wall. A 25 lb pail of the PCR is close to $300.

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[Wildflush]

Personally I would spend $14 at Harbor Freight for a moisture meter. Takes away the guesswork. I grew up using stoves but have been surprised to find some wood that I thought was ready still at 24%.

As others have said an insulated liner will keep flue gas warm and help reduce condensation. I use double wall chimney pipe inside and insulated Class A piping outside exposed to the elements. Running hot STT 550-650 is also key. As you already know you are at risk for a chimney fire.

 

[gthomas785]

I really don't know the history of the wood. It was delivered last fall.

Last fall, as in 2022 fall? No way that's ready to burn. Even if they say it's "seasoned"

 

[GrumpyDad]

Good to know, thank you. How would you insulate a production-made product like this liner?

I'll look into chimney extensions.



Bought from a pro, I really don't know the history of the wood. It was delivered last fall. Covered since delivered. As the Hearthstone 3 is such a small stove, I've had to split every single piece 2-3 more times each, just for fitment issues.

This wood isn't a problem in the other 6 chimneys I have. They are all fireplaces, however. This is the only wood stove. And the only one with an issue.

I burned 40% MC wood in a fireplace without a problem, and have little to no creosote in the fireplace chimney.
The stove is another matter. I made the mistake of burning REALLY low and slow without much of a coal bed, so my wood was just smoldering. Stove was staying at 300+ though STT, but little did I know what was happening. My doors were coated in thick creosote as was my flue pipe. A good hot burn one day cleaned it all up, and lite off some of the creosote in the stove pipe which scared the crap out of me.
Im amazed to see you had such a clog in your chimney pipe, that's crazy...but hey we love seeing pictures on these forums so, thanks for that

 

[GrumpyDad]

Last fall, as in 2022 fall? No way that's ready to burn. Even if they say it's "seasoned"

I had wood delivered last fall that is ready, including the oak. It seasons in a massive pile of firewood left outside in the rain, snow, etc. I normally never get ready to burn wood from this guy, so I was rather surprised. I suspect that when he gets wood he just splits and piles it up and then uses from the front to the back, and that I received the stuff toward the back before they reup'd for the season. Heck it may be 5-6 years old, who knows.

So there is a possibility, the reality is usually that seasoned means, 'Split during the summer and left in a giant pile in the rain'
Id love to know what a firewood dealer considers unseasoned? Is it literally chopped down and split the same day, delivered via water chute?

 

[gthomas785]

I had wood delivered last fall that is ready, including the oak. It seasons in a massive pile of firewood left outside in the rain, snow, etc. I normally never get ready to burn wood from this guy, so I was rather surprised. I suspect that when he gets wood he just splits and piles it up and then uses from the front to the back, and that I received the stuff toward the back before they reup'd for the season. Heck it may be 5-6 years old, who knows.

So there is a possibility, the reality is usually that seasoned means, 'Split during the summer and left in a giant pile in the rain'
Id love to know what a firewood dealer considers unseasoned? Is it literally chopped down and split the same day, delivered via water chute?

I don't know what your definition of "ready" is but I'm sure it's different from mine. Most firewood suppliers will pile up their wood over the summer and call it seasoned. If you're lucky to get the first scoop off the sunny side of the pile then you'll be pleasantly surprised, but otherwise it's not drying much. If it's been sitting 5-6 years in a pile that's not a good thing either and probably would have quite a bit of rot in it.

You can get unseasoned wood, it's called green. I usually order green firewood to save money. It is cut and split to order from fresh logs and delivered. Oak needs 3 years from the time it's stacked. Most other hardwoods will be ready in 2 years if stacked up and covered.

 

[delagem]

I only had glazed creosote when I ran my non-EPA stove at low temps. Was mostly in the same area as yours, near the top of my chimney. Glazed creosote is the most dangerous type of buildup.

Do you use any products to prevent this issue? Creosote powder that you put over your coals? or other solutions?

What does the stack look like when you're running the stove? Lots of smoke?

I bought a moisture meter, we'll see what I get for readings.

I never used any creosote prevention products, but I guess I'll need to start. Didn't know they made a powder, only ever seen the logs (which are on clearance at WallyWorld right now!).

Stack did look smoky. We ran it choked down low (not intentionally, that's just the way the stove runs with no decent air inlet), obviously exacerbating the problem.

Agreed that running the liner up by itself was a big mistake. I'll look into the Class A Extension that bholler mentioned.

My understanding is this is an insulated liner. Double wall. Are you guys suggesting really suggesting I insulate an insulated liner?

I'm surprised nobody is concerned about the lack of air inlets on the stove. Literally one opening, the size of my thumbnail! For the entire stove. I am not exaggerating. Hearthstone sold a kit to allow more air to be introduced, but that was 40 years ago, they can't be found nowadays.

It seems the lack of air into the fire (causing a slow, smoky burn), combined with the incorrectly run liner (extending beyond the chimney, exposed) are the 2 big issues here.

Does that seem correct?

 

[gthomas785]

Double wall is not insulated. Insulated means it is physically wrapped with ceramic fiber insulation.

 

[EbS-P]

I bought a moisture meter, we'll see what I get for readings.

I never used any creosote prevention products, but I guess I'll need to start. Didn't know they made a powder, only ever seen the logs (which are on clearance at WallyWorld right now!).

Stack did look smoky. We ran it choked down low (not intentionally, that's just the way the stove runs with no decent air inlet), obviously exacerbating the problem.

Agreed that running the liner up by itself was a big mistake. I'll look into the Class A Extension that bholler mentioned.

My understanding is this is an insulated liner. Double wall. Are you guys suggesting really suggesting I insulate an insulated liner?

I'm surprised nobody is concerned about the lack of air inlets on the stove. Literally one opening, the size of my thumbnail! For the entire stove. I am not exaggerating. Hearthstone sold a kit to allow more air to be introduced, but that was 40 years ago, they can't be found nowadays.

It seems the lack of air into the fire (causing a slow, smoky burn), combined with the incorrectly run liner (extending beyond the chimney, exposed) are the 2 big issues here.

Does that seem correct?

Double wall flex liner is not insulated. They use metal that’s is so thin they must wrap it twice. Recommendation from the pros here is to skip the double smooth wall liner and go for mid to heavy weight.

You should look into measuring flue gas temps.

 

[GrumpyDad]

I don't know what your definition of "ready" is but I'm sure it's different from mine. Most firewood suppliers will pile up their wood over the summer and call it seasoned. If you're lucky to get the first scoop off the sunny side of the pile then you'll be pleasantly surprised, but otherwise it's not drying much. If it's been sitting 5-6 years in a pile that's not a good thing either and probably would have quite a bit of rot in it.

You can get unseasoned wood, it's called green. I usually order green firewood to save money. It is cut and split to order from fresh logs and delivered. Oak needs 3 years from the time it's stacked. Most other hardwoods will be ready in 2 years if stacked up and covered.

ready meaning less than 20% MC.

 

[bholler]

I bought a moisture meter, we'll see what I get for readings.

I never used any creosote prevention products, but I guess I'll need to start. Didn't know they made a powder, only ever seen the logs (which are on clearance at WallyWorld right now!).

Stack did look smoky. We ran it choked down low (not intentionally, that's just the way the stove runs with no decent air inlet), obviously exacerbating the problem.

Agreed that running the liner up by itself was a big mistake. I'll look into the Class A Extension that bholler mentioned.

My understanding is this is an insulated liner. Double wall. Are you guys suggesting really suggesting I insulate an insulated liner?

I'm surprised nobody is concerned about the lack of air inlets on the stove. Literally one opening, the size of my thumbnail! For the entire stove. I am not exaggerating. Hearthstone sold a kit to allow more air to be introduced, but that was 40 years ago, they can't be found nowadays.

It seems the lack of air into the fire (causing a slow, smoky burn), combined with the incorrectly run liner (extending beyond the chimney, exposed) are the 2 big issues here.

Does that seem correct?

Obviously you need to get the missing parts for the air intake you know that so I didn't think pointing it out was nessecary. Although I am surprised you decided to use a stove in that condition. And as others said a 2 ply liner is not an insulated liner

 

[EatenByLimestone]

I bought a moisture meter, we'll see what I get for readings.

I never used any creosote prevention products, but I guess I'll need to start. Didn't know they made a powder, only ever seen the logs (which are on clearance at WallyWorld right now!).

Stack did look smoky. We ran it choked down low (not intentionally, that's just the way the stove runs with no decent air inlet), obviously exacerbating the problem.

Agreed that running the liner up by itself was a big mistake. I'll look into the Class A Extension that bholler mentioned.

My understanding is this is an insulated liner. Double wall. Are you guys suggesting really suggesting I insulate an insulated liner?

I'm surprised nobody is concerned about the lack of air inlets on the stove. Literally one opening, the size of my thumbnail! For the entire stove. I am not exaggerating. Hearthstone sold a kit to allow more air to be introduced, but that was 40 years ago, they can't be found nowadays.

It seems the lack of air into the fire (causing a slow, smoky burn), combined with the incorrectly run liner (extending beyond the chimney, exposed) are the 2 big issues here.

Does that seem correct?

Let’s rule out the wood before laying blame.

Wood moisture is the leading culprit in wood burning issues. Then usually the chimney.

 

[delagem]

Double wall flex liner is not insulated. They use metal that’s is so thin they must wrap it twice. Recommendation from the pros here is to skip the double smooth wall liner and go for mid to heavy weight.

You should look into measuring flue gas temps.

Ah, ok. When I looked into the inserts, it seemed the options were single wall and insulation, or the double-wall. Thank you for the clarification.

I don't seem to have a problem below the top of the chimney, so I'll start with figuring out that.

I wanted the top of the pipe to be above all the adjacent fireplace caps (there's 5 of them on this one chimney), but maybe that was a mistake? Should I leave it the same height as the other caps? I rarely use the fireplaces, the caps are just there to keep bats and birds from getting in.

I'll get a thermometer on there, thank you.

 

[delagem]

Obviously you need to get the missing parts for the air intake you know that so I didn't think pointing it out was nessecary. Although I am surprised you decided to use a stove in that condition. And as others said a 2 ply liner is not an insulated liner

The manual seemed to indicate that using the manual inlet (photo 2 in my first post of this thread) would allow enough air in, in the event of the electronic control not working (power outage, for example). Clearly it was inadequate. I did not know that, at the time.

 

[bholler]

The manual seemed to indicate that using the manual inlet (photo 2 in my first post of this thread) would allow enough air in, in the event of the electronic control not working (power outage, for example). Clearly it was inadequate. I did not know that, at the time.

It may not be inadequate at all. Again we don't know temps of the stove or the exhaust or the moisture content of the wood