Heavy creosote build up

[Murray01]

Recently purchased a cabin from my father in law that has a Blaze King model KEJ 1102. We only use it during the shoulder seasons and never in the winter. I have downloaded the instruction/installation manual and have been reading up on the stove. This summer I finally gave it a good cleaning. Last year I found a brand new catalytic burner tucked away in a cupboard, once I figured out what it was for I inspected the one in the stove and discovered that the old one had about one quarter of the honeycomb was rotted out. I replaced the old one, that helped big time with getting the thermometer into the active zone. This year I took all the stove pipe apart and gave it a good clean, I have about 80% fine black/brown dust and 20% creosote(hard flakey material) cleaned best I could but couldn’t get to bare metal. Same with the chimney 80/20 ratio. Next I turned to the broken fire bricks on the back of the firebox, I had to pry them out, they were stuck on due to creosote buildup, likewise with the sides and to a lesser extent the bottom bricks. Scraped the buildup off the sides and back of the firebox best I could. The rest of the firebox was 2 days chipping and scraping creosote, in the corners I encountered 1/2”-3/4” of creosote. Between the outside wall and a firebox wall is a space about 3/4”, it was plugged full of creosote, with a small screwdriver and bent coat hanger I cleaned it best I could. Can’t really get my fingers in there but I think I got most of it. All in all I collected 2 1kg coffee tins of creosote plus whatever the vacuum cleaned up, likely another coffee tin worth.
What I know about about the stove and pipe:
Blaze King model KEJ 1102 7”pipe
Single wall stove pipe 8’ straight up into 8’ of insulated chimney
Door and window gaskets leaking, both replaced yesterday.
Wood is primarily Jack pine, I’ve been mixing 10 year out seasoned wood with 2 year old seasoned wood. I don’t own a moisture meter but will get one.

I think my problem is a combination of a mixed bag of wet/dry wood and not running stove hot enough long enough. The other issue is poor maintenance while my father in law was using the stove. As I was cleaning the buildup I kept thinking that I’m lucky that I didn’t have a creosote fine in the firebox.

An suggestions/ideas/criticisms are welcomed. This is my fire cat wood stove. Thank you for reading this long winded post.

 

[Highbeam]

These things get pretty nasty in the firebox. It is common to pop off chunks of 1/2" thick crusty creosote from the corners especially. It's kinda like a black lava cookie. Only with a very hot fire can the firebox somewhat self clean.

The chimney on a BK is also not known to be as clean as you might expect for a stove with such a low emissions rating and high efficiency. See, to burn at such a low rate means the exhaust gas temperature often falls below the condensation temperature of water so the flue is exposed to a lot of wetness and dry cycles which accumulates debris. Usually black, often flakey. Over 90% of the time the stoves are run on low, statistically, according to industry research and BK. Low and slow is where it's at. That just means creosote in the firebox and especially with pine.

Oh and that lame void behind the inner steel panels is a bugger to clean. It is easier to keep the void clean than to try and recover from years of neglect.

I get a lot more creosote in my stove and chimney of the BK than a did with a modern noncat on the same hearth and using the same fuel.

Since this is a new stove to you and you checked the gaskets, please check the bypass frame and gasket. Hopefully it's nice and flat and not melted.

 

[Ctwoodtick]

do you have any pics of the chimney after you swept it out. I know you said that you couldn’t get to bare metal. Did you notice any hard shiny buildup that couldn’t be removed? Almost like a layer of black glassy looking stuff.
Sounds like you removed a bit of stage 1 and 2 creosote. Just making sure what’s left in chimney is not stage 3 creosote.

 

[BKVP]

OP hit it on the head! Lack of maintenance. I have owned 3 of our King models. 1102, 1107 and now KE40. All were tested and tortured in my home before they hit the market. None has had the accumulation referenced in this post.

The combustor failure was likely due to the leaking glass and door gasket. If fuel was wet or snow laden, that too could have resulted in thermal shock.

Follow operating instructions to have periodic high burns to keep creosote issues in the firebox to a minimum.

Your 1102 does not have a bypass gasket or retainers. The bypass is 1/2" steel and therefore no need to look for them.

If your flue collar measures 7", that stove was purchased in Canada. All 1102's sold in the USA were 8" diameter flue collars.

As for cleaning behind the baffles, go to your local welding supply store (our TrueValue has welding supplies) and purchase a round wire, flexible shaft brush. That and burning correctly will be of great benefit.

I've also owned other EPA (1990's) non catalytic stoves (2) and both had clean 15' chimneys....just like my 3 King stoves.

Proper operation, conditioned fuel and annual maintenance allows any modern stove to provide warmth and peace of mind.

Good job O.P.

BKVP

 

[Murray01]

These things get pretty nasty in the firebox. It is common to pop off chunks of 1/2" thick crusty creosote from the corners especially. It's kinda like a black lava cookie. Only with a very hot fire can the firebox somewhat self clean.

The chimney on a BK is also not known to be as clean as you might expect for a stove with such a low emissions rating and high efficiency. See, to burn at such a low rate means the exhaust gas temperature often falls below the condensation temperature of water so the flue is exposed to a lot of wetness and dry cycles which accumulates debris. Usually black, often flakey. Over 90% of the time the stoves are run on low, statistically, according to industry research and BK. Low and slow is where it's at. That just means creosote in the firebox and especially with pine.

Oh and that lame void behind the inner steel panels is a bugger to clean. It is easier to keep the void clean than to try and recover from years of neglect.

I get a lot more creosote in my stove and chimney of the BK than a did with a modern noncat on the same hearth and using the same fuel.

Since this is a new stove to you and you checked the gaskets, please check the bypass frame and gasket. Hopefully it's nice and flat and not melted.

Thank you for the reply. You mention:

It is common to pop off chunks of 1/2" thick crusty creosote from the corners especially. It's kinda like a black lava cookie. Only with a very hot fire can the firebox somewhat self clean.

I’m worried that if I got a hot enough to burn off the creosote remaining I’d start the creosote on fire and melt the stove or at least have a out of control fire on my hands. As much creosote as I removed from the firebox there is still lots in there. My plan is to keep chipping away at it. No gasket on the bypass door, appears to seal nicely. Once the cat thermometer is in the active zone for an hour or so I can look into it and see it glowing orange and there was zero creosote build up anywhere near the cat and the bypass door so I’m assuming thats working correctly.

 

[Murray01]

do you have any pics of the chimney after you swept it out. I know you said that you couldn’t get to bare metal. Did you notice any hard shiny buildup that couldn’t be removed? Almost like a layer of black glassy looking stuff.
Sounds like you removed a bit of stage 1 and 2 creosote. Just making sure what’s left in chimney is not stage 3 creosote.

Some black and shiny material mostly dull but very hard, fingernail won’t touch it but I could scrape it off with a screwdriver. Had to Google the stages of creosote which brought me to the chemicals you sprinkle on your fire that’s supposed help with the breakup of creosote, positive reviews but I can post a positive review on topics I know nothing about.
Is the creosote chemicals worth it? If so what would be a suitable product?
Pictures are at the top of the chimney. If they don’t come through I’ll reread the section on posting pictures and try again.
Thank you for your suggestions

 

[BKVP]

Thank you for the reply. You mention:

I’m worried that if I got a hot enough to burn off the creosote remaining I’d start the creosote on fire and melt the stove or at least have a out of control fire on my hands. As much creosote as I removed from the firebox there is still lots in there. My plan is to keep chipping away at it. No gasket on the bypass door, appears to seal nicely. Once the cat thermometer is in the active zone for an hour or so I can look into it and see it glowing orange and there was zero creosote build up anywhere near the cat and the bypass door so I’m assuming thats working correctly.

You won't melt the stove. If you have a weed burner torch, you can burn it off outside.....

 

[Murray01]

OP hit it on the head! Lack of maintenance. I have owned 3 of our King models. 1102, 1107 and now KE40. All were tested and tortured in my home before they hit the market. None has had the accumulation referenced in this post.

The combustor failure was likely due to the leaking glass and door gasket. If fuel was wet or snow laden, that too could have resulted in thermal shock.

Follow operating instructions to have periodic high burns to keep creosote issues in the firebox to a minimum.

Your 1102 does not have a bypass gasket or retainers. The bypass is 1/2" steel and therefore no need to look for them.

If your flue collar measures 7", that stove was purchased in Canada. All 1102's sold in the USA were 8" diameter flue collars.

As for cleaning behind the baffles, go to your local welding supply store (our TrueValue has welding supplies) and purchase a round wire, flexible shaft brush. That and burning correctly will be of great benefit.

I've also owned other EPA (1990's) non catalytic stoves (2) and both had clean 15' chimneys....just like my 3 King stoves.

Proper operation, conditioned fuel and annual maintenance allows any modern stove to provide warmth and peace of mind.

Good job O.P.

BKVP

Thank you for your reply.
You refer to a “round wire flexible shaft brush” not sure exactly what you are referring to but I’m thinking a bottle brush only with steel bristles?
With a name like BKVP I’m assuming you are associated with Blaze King, recently purchased a door and window gasket and not knowing what I’m doing(product wise) wanted to stay with OEM. Priced out the parts at Amazon.ca $115, local Home Hardware is an authorized BK dealer, total bill was $69 plus $20 shipping. Was pleasantly surprised, will definitely be purchasing any parts through Home Hardware in the future.

 

[BKVP]

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Mine is like this and I put it into my cordless drill. Yes, I am the Vice President of the company. The 1102 is a great stove, you should really enjoy it.

BKVP

 

[Highbeam]

Don't be afraid of a fire in your firebox. It's supposed to happen that way. If the creosote bothers you I wouldn't spend much time chipping at the old firebox debris until after you've burned some long and hot fires to dry them out. It's much easier then. I try to do this before the summer break. It'll just get gunky again in the fall. You'll see.

 

[Ctwoodtick]

Some black and shiny material mostly dull but very hard, fingernail won’t touch it but I could scrape it off with a screwdriver. Had to Google the stages of creosote which brought me to the chemicals you sprinkle on your fire that’s supposed help with the breakup of creosote, positive reviews but I can post a positive review on topics I know nothing about.
Is the creosote chemicals worth it? If so what would be a suitable product?
Pictures are at the top of the chimney. If they don’t come through I’ll reread the section on posting pictures and try again.
Thank you for your suggestions

View attachment 314907 View attachment 314908 View attachment 314909

That does not look like a lot of shiny hard build up to me. I’m not sure how much it extends down the chimney, but if it’s only a couple feet and it is as it appears in the picture, I think you’re probably ok. I’m not a professional though, so if a pro does chime in about these pictures, I would defer to that.

 

[BC_Josh]

Well, a lot of time has passed since the orginal post. However, I wanted to add: a chimney sweeper and stove installer told me that a lot of folks burn their catalytic stoves too low, too often, and this causes creosote buildup. He said you should originally get the fire going so that it has a small flame that neither grows nor shrinks and leave it at that. And, after awhile turn it up a bit.... but this seems to contradict the whole point of getting a catalytic stove; I did it so I could smoulder wood for long periods of time, but he has a point.

 

[kennyp2339]

Change the single wall pipe to dvl, it will keep the flue gasses hotter which = less cleaning

 

[stoveliker]

In my experience they don't know what they are talking about.

With dry wood (!) and a chimney that is proper (draft and insulation) there is no issue running as low as the mfg allows by the design of the air control.

 

[BC_Josh]

In my experience they don't know what they are talking about.

With dry wood (!) and a chimney that is proper (draft and insulation) there is no issue running as low as the mfg allows by the design of the air control.

It can be hard to parse the info out there. Seems like a lot of opinions. At any rate, I had a small chimney fire on the cap of my chimney last week and I have a BK with a cat and a lot of creosote had built up after a few months of burning, but I suspect it was with a cold snap that caused a lot of condensation in the upper portion of the chimney that would've been very cold at that time. Cold snap is over anyway.

 

[stoveliker]

How dry is your wood?
What is your burning procedure? Start with "getting wood from the stack).

Creosote happens when there is too much water in the exhaust AND the pipe is too cool.
Proper operation of the stove, with good wood, and a proper installation, should allow you to burn without such issues.

Many folks on here do so.

 

[BC_Josh]

How dry is your wood?
What is your burning procedure? Start with "getting wood from the stack).

Creosote happens when there is too much water in the exhaust AND the pipe is too cool.
Proper operation of the stove, with good wood, and a proper installation, should allow you to burn without such issues.

Many folks on here do so.

The installer has been doing it for years.... hard to see a problem with the install.... but wouldn't entirely rule out any variable without more knowledge. And, my wood is at 14% moisture content. I did a lot of slow burning, though, and my stove even did a 24 hr burn time, while it is advertised as a 20 hr burn (I have a cat stove, a BK).

 

[stoveliker]

Me too, BK (37 hrs on the 30.2 model).

How did you measure the 14 percent?

Honestly, practice shows one does not need to end up with chimney fires when doing things right. Hence my questions, aimed to pinpoint the culprit here.

Without detailed answers, it'll be impossible to do so, and your situation won't change.

 

[BC_Josh]

Me too, BK (37 hrs on the 30.2 model).

How did you measure the 14 percent?

Honestly, practice shows one does not need to end up with chimney fires when doing things right. Hence my questions, aimed to pinpoint the culprit here.

Without detailed answers, it'll be impossible to do so, and your situation won't change.

I have a Blaze King brand moisture meter and measured splits in the center right after cutting them open.

Another couple variables: there is a gas furnace in the basement and an intake vent right next to my BK stove, so since I've turned off the fan, a negative pressure situation seems to be resolved, and now fires get roaring easily, when I start them, whereas they had a hard time doing that before.

My attic is not insulated, and my chimney goes through it before it goes outside. Our recent cold snap could've caused a lot of condensation inside the top of the chimney.

But, yeah, I would think that my stove should be able to run on lower thermostat settings. If it is left on too high, I get cooked out of my house, too hot in here!

Argh. Thanks. Josh

 

[stoveliker]

I have a Blaze King brand moisture meter and measured splits in the center right after cutting them open.

Another couple variables: there is a gas furnace in the basement and an intake vent right next to my BK stove, so since I've turned off the fan, a negative pressure situation seems to be resolved, and now fires get roaring easily, when I start them, whereas they had a hard time doing that before.

My attic is not insulated, and my chimney goes through it before it goes outside. Our recent cold snap could've caused a lot of condensation inside the top of the chimney.

But, yeah, I would think that my stove should be able to run on lower thermostat settings. If it is left on too high, I get cooked out of my house, too hot in here!

Argh. Thanks. Josh

okay.
If measured on wood that has been in the home for 24 hrs so it is up to room temperature, with the pins parallel to the grain on the fresh surface, *and pressed deeply (best is completely) into the wood*, that measurement should be fine.

The chimney being inside, barring the attic and the last part, is great.

What does matter is how tall your chimney is; each BK will have its own "minimum" setting below which it won't work well, as the chimney will be too cool to have sufficient draft to pull in enough oxygen to the smoldering. The cat might even drop out of he active zone - and then you end up with a lot of crud in the chimney. So how tall is that chimney? From the basement remark, this suggests, basement, main floor, attic, + a few feet above the roof, correct?
Single wall pipe will allow the gases to cool even faster (as Kenny above remarked).

Running a BK on low one needs to do all one can to keep the chimney gases above 220 (best 250 imo) or so (at the *exit* of the chimney) so things don't condense. Single wall pipe is not really suitable for that.

Also: are you properly charring the wood before you turn the stove down? (What wood species, and how long?)

 

[BC_Josh]

okay.
If measured on wood that has been in the home for 24 hrs so it is up to room temperature, with the pins parallel to the grain on the fresh surface, *and pressed deeply (best is completely) into the wood*, that measurement should be fine.

The chimney being inside, barring the attic and the last part, is great.

What does matter is how tall your chimney is; each BK will have its own "minimum" setting below which it won't work well, as the chimney will be too cool to have sufficient draft to pull in enough oxygen to the smoldering. The cat might even drop out of he active zone - and then you end up with a lot of crud in the chimney. So how tall is that chimney? From the basement remark, this suggests, basement, main floor, attic, + a few feet above the roof, correct?
Single wall pipe will allow the gases to cool even faster (as Kenny above remarked).

Running a BK on low one needs to do all one can to keep the chimney gases above 220 (best 250 imo) or so (at the *exit* of the chimney) so things don't condense. Single wall pipe is not really suitable for that.

Also: are you properly charring the wood before you turn the stove down? (What wood species, and how long?)

Thanks for the response; yes, I press in the pins like the manual for the moisture meter recommends. I also do it parallel to the grain of the wood. And, if I leave it inside the house for awhile, it actually gets down to 13% moisture. I'm burning mostly fir but also some larch. All the fir has the bark removed, the larch has the bark intact (and seems more sappy). I burned almost all larch recently with the cold snap. Now I'm only burning a mix of fir and larch. Those are the only two kinds of wood I have. Both are seasoned and dry.

You're right about the configuration of the house; there is a basement (which is 2/3 crawl space, the rest has a couple of small rooms with storage and the hot water tank and furnace). Then the main floor, and an attic which is not used for anything, not even storage, it's a crawl space too with floor joists and pink insulation on top, can only stand up in the middle of it, since it is a steep pitch and a hip roof design on a small house. The chimney is about six feet long inside the main floor, then another seven feet or so inside the attic, then a few feet above the roof. With the floor thickness and the roof thickness, the whole chimney is not all that long, come to think of it. Seventeen, maybe eighteen feet.

The chimney is double wall stainless steel pipe all through the attic and outside. I think on the inside of the house it is single wall though. And, then there is an insulated collar in the attic as well, since it goes through the wood framing and pink fiberglass insulation.

I am charring wood before turning down the stove, I do the recommended 20-30 min's as it states in my BK Sirroco model manual.

Another thing: I do notice a lot of smoke outside when I am first firing up the stove with the bypass open; I've read from other BK owners that this is normal at least to their systems.

It does seem like a condensation issue is the problem here. How to solve it though?..... that's the hard part. If I turn up the stove too much I'm in a sauna. My house is only 875 sq/ft on the main floor.

 

[stoveliker]

all that you write above seems good. 18 ft is fine, normally (if you're at sea level..., see the manual).

Indeed upon start up there's smoke. (But as I noted in the other thread, close the bypass as soon as the door is closed when the cat is still active).

Double wall is what I'd recommend as a first step, as I can't see much else (other than the bypass thing).

 

[BC_Josh]

all that you write above seems good. 18 ft is fine, normally (if you're at sea level..., see the manual).

Indeed upon start up there's smoke. (But as I noted in the other thread, close the bypass as soon as the door is closed when the cat is still active).

Double wall is what I'd recommend as a first step, as I can't see much else (other than the bypass thing).

My manual says 15' mininum between stove top and chimney top. I don't see anything in it about sea level, but I'm at 1755 ft elevation.

I always close the bypass after the needle on the cat probe goes to the active zone.

It appears to be single walled chimney inside the main floor, but then goes to double walled after that, after it goes through the attic.
The single walled would be mostly warmer since it's inside the house, but I suppose with cold air if it goes down the chimney.... But, the initial fire is partly to warm the chimney to increase the draw. After it's warmed up, I would assume it stays warm being inside the house and doesn't have any real cold acting against it.

A few weeks before I got my chimney serviced, I looked up with a flashlight and mirror, it looked pretty good, a bit of ashy soot, grey in colour. But, then after a chimney fire, I noticed a bit of gunked up creosote right at the bottom of the chimney, where it meets the stove. Again, we did have a wicked cold snap here (like everywhere else that got that shocker of the Arctic Dome ooze down from the north).

I do have a chimney cleaning kit, a soot eater and I'm planning on cleaning out the chimney again this coming week to see how it's been doing in the warmer temps.

 

[stoveliker]

I think they recommend to add 1 ft per 1000 ft of elevation (lower air pressure will decrease draft).
So for you I'd say 17' is the recommended height. You're at 18, so nothing off there.

What you describe here does.seem like something is going not well with the draft.

 

[all night moe]

I may have missed this .... is the top of your chimney within specs.
Is it 2ft above the ridge if at or close to it? If your not near the ridge specs call for 10ft between cap and roof .... level line.

I probably missed this. I didn't go back and reread.