Possible Small Chimney Fire - Need advice

[elmo_4_vt]

Hey All - First time using a free standing stove and I'm not sure I'm doing everything 100% right, since as the title suggests, I think I may have had a small chimney fire tonight. I have a new BK Chinook 30.2 and I've been using it for a few weeks since finishing the install. I haven't burned much in the past week since temps in my area have been pretty moderate (Delaware has been in the 50's or higher). So tonight it's getting cold again and I loaded up the box to start the fire. Fire got going well, and was pretty hot with it hitting the "Active" zone right about 18 minutes when I closed the bypass. Manual says to keep the thermostat on high for a good fire for 20+ minutes to help burn off the creosote in the box and char the new wood, and tonight at about the 20 minute mark, I could hear something strange, which was best described on other threads here as rice-krispies running down the stove pipe. As soon as I realized what it was, or at least what it may be, I turned down the stove and the noise stopped within about 20 seconds. It was making that noise for around 90 total seconds between me hearing it, using a laser thermometer on the interior stove pipe, going outside to look at the chimney, and coming back in and to turn the stove down. The interior double wall pipe was about 230-250* exterior temp to about 8' up, then under 200* up to where it enters the ceiling box. The Chimney outside had no signs of anything wrong - No sparks, just light/white smoke that seemed normal and showed no temp increase above ambient, if the laser thermometer even works that far away.

So here is the real question - Do you think it was an actual chimney fire or am I just being paranoid?

I am seeing more creosote inside the fire box and on the glass then I was used to in my last Osburn insert, and I'm not sure if that's normal or not. I'm burning seasoned wood that is under 20%, at least on the pieces I've checked, but will check more to make sure. Wood I'm on now is a bit of a mix of species, but all hard wood. During the steady-state burn, I normally run the thermostat at around the 4:00 position and I'm very happy with the 12+hr run times and it's all the heat my house needs. Do I need to run hotter and just vent with outside air?

I know a double wall stove pipe thermostat would have been helpful in diagnosing issues, and one is on order now.

I'm just a little nervous about next time I run it on high with a new load of wood? Is there anything else I should do other make sure I watch things closely?

I don't have the equipment to clean the chimney myself at the moment, but was planning on buying and cleaning things in the spring. Should I get it cleaned/inspected by a professional sweep soon? Or even immediately before I continue use?

Thanks and sorry for all the questions. Did a lot of reading tonight but didn't see much about what happens after a small fire like this, only bigger fires and damaged equipment.

Don

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[MongoMongoson]

To me, it sounds like your stove pipe just got hot and started to make some noise like it does when the temperature ramps up quickly. Did you have any smoke in the house, from stove pipe paint getting really hot? Could you hear a fire inside your stove pipe? From experience, I think you would hear it. Not just the pipe making pinging/clicking but the actual flames in the pipe making a low-pitched spooky rumble/whooshing sound I cannot describe.

Can you see on top of your roof? If you had a chimney fire, crispy black embers would be found on your roof or somewhere outside.

I learned a couple of things from my chimney fire. Even when you are sure you are doing everything right, inspect a new setup early and often until you really are sure everything is working as expected. That was number one. If this set up is new to you and you have been running it since it got cold, yes you should inspect it or have it inspected.

Number two is that the peace of mind you get from that inspection or mid season cleaning is worth a lot more than it costs in time or money to perform the inspection/cleaning.

I can't give you any advice for running your cat stove, but it doesn't sound like a chimney fire to me. A little healthy fear is healthy when you have a fire in a metal box in your house and inspecting your pipe and chimney will help you get over that fear.

I just did my January inspection today and it was all looking good.

By the way, my chimney fire was a small one. No damage done and I had my chimney and stove pipe inspected afterwards by a certified sweep, and was told it was ALL fine to use. I replaced the stove pipe anyway and still use the same class A chimney.

 

[ABMax24]

I agree with the above. Doesn't sound like you had a chimney fire. Particularly based on the outside temps of the double wall, my double wall regularly runs 250f on the outside. You probably got it hot, the stainless inner wall of the double wall expands considerably when heated, when it gets hot fast it can make popping sounds like you heard.

 

[Poindexter]

I think you are getting to know your stove, probably did not have a chimney fire, probably did overheat your pipe, but I got some questions.

Probably your previous Osborne insert was on a different chimney pipe, yes? How long ago was the chimney in the picture above installed or most recently cleaned?

How many cords have you burned since the chimney was installed or most recently cleaned?

What is your total stack height on this stove? It is a pretty install, but it will be tricky to brush that pipe from the bottom up when there is a bunch of snow on your roof.

Please stop right now today getting "char" and "bake" confused. It is turning into my personal pet peeve this year since I can't yell at patient's about their preventative health choices. My rage is being I think displaced, maybe transference. I was always a lot better at nutrition than I was at psych.

Char is when you burn all the fuzz off the surfaces of the new fuel. New fuel with the fuzz on it presents nearly infinite surface area to be burnt and gives a big wallop of emissions while it is being CHARRED.

After the combustor is engaged, and you are running on high for 20-30 minutes you are BAKING the last of the moisture out of your fresh fuel load. Once your new fuel has been in that 600+ degree oven for 20-30 minutes you have pretty well baked the moisture content down to zero percent and now it is safe to turn the thermostat down. In the manual for my 30.0 it says 30 minutes on high. I haven't read or downloaded a manual for the 30.2 boxes, 20 minutes with fuel at or under 20% MC is probably fine if you see it in print in your manual and your fuel really is 20% or less. This is not an area to screw around or play fast and loose with the long term health of your expensive stove.

Not mad at you personally but char and bake are distinctly different processes in the burn cycle. Your char step should be completed before you close the bypass door to engage the combustor and begin the bake.

You stated, I triple checked, that you loaded hardwood at "less than 20% MC" and were able to engage your combustor in 18 minutes from what appears to have been a cold start. Can't be done safely from a cold start. If that was a cold start I will bet you US$500 cash money that your flue temp got up to near 1800 degrees F to get the combustor engaged in 18 minutes. Your local fire marshal will poop building materials if your flue temps are routinely at or near 1000 degrees F, never mind higher.

I can get from cold start to active combustor in about 25 minutes, using spruce at 14 % MC and limiting my exhaust gas temp to 1000 dF routinely. When I go find or trade into some birch at or very close to 20% MC, on a cold start, with my 30.0 Ashford, flue gas temp limited to 1000 dF, is routinely 30-35 minutes to clean plume.

As an EPA regulated burner in a "non attainment area," I am required by regulation to get from a cold stove to a clean exhaust plume (as evaluated from the street in front of my home without a warrant) by an EPA certified VEE - Visual Emission Inspector - in twenty minutes or less. It simply cannot be done safely. To meet the letter of the law I have to run egregiously unsafe flue gas temps, and I simply will not do that.

The rule that regulated burners need to get from cold iron to clean plume in 20 minutes (limited to 50% opacity) is not safely attainable with fuel at 20% MC in catalytic stoves. I have publicly testified about this to my local government twice, and been published in my local newspaper once. It is a stupid rule that should not be on the books. If you get ticketed for this, call me. I will show up in court beside you in Carhart's with saw dust on my boots and an Alaskan attitude in my heart.

#1. get a flue gas probe. The kind that you have to drill your double wall to install. Follow the directions that come with your unit, most likely it should be 18-30" above your stove collar. Limit your start up temps to 1000 degrees F or less. Forget trying to get the combustor engaged in under 20 minutes. Limit your flue gas temp to 1000 degrees F and see how long it takes.

#2 Pending your responses, my guess is the rice krispie noises was your pipe cooling back down after having been dangerously overheated.

 

[stoveliker]

I think I do not agree with Poindexter.
I do have a flue probe. Not instantaneous (Auber) but a condar one.
I have been able to close the bypass within 20 mins with the probe not going above 850. The real temperature may have been higher (slow probe).

I also do not believe the "fuzz argument". That fuss is hard to see, constitutes an incredibly small mass with an incredibly large surface area. As a result, when a flame touches it, it's immediately gone.
The fuzz (loose fibers at the surface of the wood) is gone long before all is black.

Yes , the charring phase bakes the wood, and its character changes over time. In my understanding, the charring (getting everything black) is preparing the fuel to be consumed in a slowly progressing glow-front during the long burn (without flames or with blue northern lights). That does not work well with wood that's still "wood color". And yes, making everything black also bakes out any remaining moisture, which is good.

That all said, (you see, all is BK owners do not agree on everything, but we are mostly united on enjoying the stove), I think you heard expansion, possibly including a flaking off of some creosote coating due to said expansion.

I would inspect the flue soon to see what its state is regarding creosote. And be there when the chimney expert does that so you can learn. In the mean time, I'd remain near the stove until it's in stable cruising mode - because then you are there during the hottest part of the cycle. The rest is at lower temperature, controlled to remain so by your Tstat. It'll ease your nerves.

 

[Poindexter]

FWIW I have fooled around a bunch of different ways trying to beat the clock on cold starts. At the end of races, my finding is heat transfer between the combustor and the welded steel box is very good.

There is no benefit in building a fire to heat the combustor, because I really have to bring the entire firebox up to temp to get the combustor up to temp. Just build the biggest fire you can, ride herd on the flue gas temp by turning the thermostat down as needed and engage when you can.

One alternative is to build a log cabin of small splits to heat the cold stove into the active zone and then do a hot reload on live coals. The EPA already has a rule for that, the cold start clock will not yet have reset when you char the big load and have a second opacity bump in your exhaust plume.

The lowest emissions route, to meet the spirit of the law, is to load the stove up as full as you can pack it, limit the cold start to 1000 degrees F flue gas; know that you are blowing away 25-30% of your fuel load (and burn time) to get to active combustor, but also know the BK stove will run efficiently enough that you will be able to do a hot reload several hours in the future with the EPA clock having been reset from the cold start.

 

[Poindexter]

@stoveliker has a strong background in chemistry and is not to be ignored or taken lightly.

I have had my stove hot enough on hot reloads to see the fuzz blacken on each split as I load it in the stove. I reloaded about two hours ago, my 30.0 is still on high long after both char and bake have been completed. My Condar flue gas probe is showing about 600 degrees F.

I am on my second Condar probe as the first had aesthetic issues, but the two are in good agreement, both in my stack and when searing meat in my BBQ pits.

I have a Raytek MT-6 (infrared) tire pyrometer with a fixed emissivity setting for flat black, from before I was married with children and had the time and money to be at the track with my car.

On high for 2+ hours (my stove is raging, but my wife is in a pleasing outfit), with exhaust gas temps at 600 dF (Condar) I see 500-525 at the stove collar (Raytek) , 290-310 dF on the outside of the double wall with the Raytek pointed next to the Condar on the double wall. and 200-210 dF (Raytek) at the (eight foot) ceiling box. Outdoor ambient just now is -30 dF.

I am accustomed to seeing my Condar show me 1000 degrees F at combustor engagement ( on cold starts with my participation) and 600 degrees 15-20 minutes after combustor engagement.

To me, 200 degrees on the outside of the double wall is in pretty good agreement with 600 degrees flue gas temp, given it takes a good 30 minutes for the outside layer of the double wall to acclimate after the stove settings were last adjusted.

My current hypothesis, pending response from the OP, was his flue gas temp was up over 1500dF at engagement, and then dropped to 600 dF in 15-20 minutes and he heard the rice krispy noise as his stack cooled down.

FWIW the handle on my loading door, measures 172 dF (Raytek) but is not yet charred to flat black.

 

[kennyp2339]

Even with DVL pipe, if you have a chimney fire, you will smell the burning metal, paint, creosote and a light haze will develop inside the house.

 

[elmo_4_vt]

Thanks for all the input guys - Really appreciate you all taking the time to help a new guy out. Under a cord so far through the stove, mainly because this thing burns so well/efficient. I'm on my second IBC tote, so somewhere between 1/3 and 2/3 cord.

As an update, no smells, creosote on the roof that I could see, and I don't think any interior haze (it was dark out) happened last night. So maybe it was just the heat dumping into the stove pipe as the box temps got high quickly? Nothing was cooling down at the point I heard the noise, but without the gas temps inside the pipe, it's really hard to tell what's going on. I should have gotten that installed sooner, just for the data point if nothing else.

In the end, I guess only getting up on the roof and looking down will tell me for sure what things look like. I'm scheduling a pro to come out to clean and verify how things look once the snow melts off later this week, and I'll be more careful about the slowly turning down the stove instead of using the thermostat as a on-off switch (between high and 4:00 settings). On the hot reload this morning, everything worked as expected and at the 15 min mark as things were getting bright in the box, I started slowly turning down the heat (6:00 to 5:30 to 5:00, etc). I never really put much thought into the 20min wording in the manual, but what you put in around the EPA requirements make sense. Not a lot a lot of people around here burn full time, so it's unlikely I'll have any issues with people complaining. In reality, the only time you see smoke and smell it is at start up, and I doubt there's anyone sitting outside with a stop-watch or that even understand the newer EPA requirements/rules.

Once I get the Condar Flue thermometer in and installed, I'll update with how the temps look during the normal start up routine and how they compare with the outside pipe temps I saw last night. Thinking about it more, I really do think I would have seen the outside black pipe temp go above 250* if there was a fire, but maybe the short duration limited the heat transfer? Thanks again for all the help.

Don

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[MissMac]

I think you are getting to know your stove, probably did not have a chimney fire, probably did overheat your pipe, but I got some questions.

Probably your previous Osborne insert was on a different chimney pipe, yes? How long ago was the chimney in the picture above installed or most recently cleaned?

How many cords have you burned since the chimney was installed or most recently cleaned?

What is your total stack height on this stove? It is a pretty install, but it will be tricky to brush that pipe from the bottom up when there is a bunch of snow on your roof.

Please stop right now today getting "char" and "bake" confused. It is turning into my personal pet peeve this year since I can't yell at patient's about their preventative health choices. My rage is being I think displaced, maybe transference. I was always a lot better at nutrition than I was at psych.

Char is when you burn all the fuzz off the surfaces of the new fuel. New fuel with the fuzz on it presents nearly infinite surface area to be burnt and gives a big wallop of emissions while it is being CHARRED.

After the combustor is engaged, and you are running on high for 20-30 minutes you are BAKING the last of the moisture out of your fresh fuel load. Once your new fuel has been in that 600+ degree oven for 20-30 minutes you have pretty well baked the moisture content down to zero percent and now it is safe to turn the thermostat down. In the manual for my 30.0 it says 30 minutes on high. I haven't read or downloaded a manual for the 30.2 boxes, 20 minutes with fuel at or under 20% MC is probably fine if you see it in print in your manual and your fuel really is 20% or less. This is not an area to screw around or play fast and loose with the long term health of your expensive stove.

Not mad at you personally but char and bake are distinctly different processes in the burn cycle. Your char step should be completed before you close the bypass door to engage the combustor and begin the bake.

You stated, I triple checked, that you loaded hardwood at "less than 20% MC" and were able to engage your combustor in 18 minutes from what appears to have been a cold start. Can't be done safely from a cold start. If that was a cold start I will bet you US$500 cash money that your flue temp got up to near 1800 degrees F to get the combustor engaged in 18 minutes. Your local fire marshal will poop building materials if your flue temps are routinely at or near 1000 degrees F, never mind higher.

I can get from cold start to active combustor in about 25 minutes, using spruce at 14 % MC and limiting my exhaust gas temp to 1000 dF routinely. When I go find or trade into some birch at or very close to 20% MC, on a cold start, with my 30.0 Ashford, flue gas temp limited to 1000 dF, is routinely 30-35 minutes to clean plume.

As an EPA regulated burner in a "non attainment area," I am required by regulation to get from a cold stove to a clean exhaust plume (as evaluated from the street in front of my home without a warrant) by an EPA certified VEE - Visual Emission Inspector - in twenty minutes or less. It simply cannot be done safely. To meet the letter of the law I have to run egregiously unsafe flue gas temps, and I simply will not do that.

The rule that regulated burners need to get from cold iron to clean plume in 20 minutes (limited to 50% opacity) is not safely attainable with fuel at 20% MC in catalytic stoves. I have publicly testified about this to my local government twice, and been published in my local newspaper once. It is a stupid rule that should not be on the books. If you get ticketed for this, call me. I will show up in court beside you in Carhart's with saw dust on my boots and an Alaskan attitude in my heart.

#1. get a flue gas probe. The kind that you have to drill your double wall to install. Follow the directions that come with your unit, most likely it should be 18-30" above your stove collar. Limit your start up temps to 1000 degrees F or less. Forget trying to get the combustor engaged in under 20 minutes. Limit your flue gas temp to 1000 degrees F and see how long it takes.

#2 Pending your responses, my guess is the rice krispie noises was your pipe cooling back down after having been dangerously overheated.

Oh my. This made my head snap around and caught my attention. I'm on my 5th winter with my sirocco 30.1, and I'd say that over the past 2 winters, I've experimented more with engaging the cat earlier and earlier. I no longer load the box up full to do a cold start. I do about one level of smaller splits across the bottom with a liberal amount of birch bark and kindling to get a fire up and running - top down. I also no longer wait until the cat probe is actually in the active zone, because i know there's a lag there. Through trial, I have determined that I can engage my cat around 14 minute mark (this would be using pine, spruce or birch as fuel) so long as I've built the starter fire properly. I don't have a temp probe in my stack. As soon as I throw the bypass shut, the cat is glowing orange which to me signals that it's hot enough to be engaged. I always leave the throttle wide open during this process, and then bake the load as per the manual for 20-30 minutes.

I know you are a super seasoned BK burner @Poindexter. I'm sure you know when it's time to flip the bypass. Curious - do you wait for the cat probe to actually tick up into the active zone, or do you flip early knowing where the lag is on your set-up?

 

[stoveliker]

The above is what I see and do too. Closing the bypass "switches" on the glow in the cat - it goes from black to glowing almost instantaneously. Indeed generally between 15-20 mins depending on how the starting fire was built (and, I presume, wood type and moisture content).

 

[begreen]

The only time I have heard that sound is when several years ago I was burning some maple that got wet in spots through leaks in the tarp. It was the only wood we had so I was burning it, but by the end of November I was getting that sound during start up, before closing down the air. I think this sound is from a layer of creosote that has formed inside the stovepipe that ignites under high temp. There isn't enough for a full-on chimney fire, but enough of a glaze to burn. We cleaned the chimney after that and got about a quart of soot and sote. That's after one month of burning or about 1/2 cord of wood. Normally, burning dry fir we get about 1/2-1 cup after 3 cords. After that, all damp pieces came into the house for a week before burning.

 

[Poindexter]

I don't go by glowing combustor. Doesn't matter what color the combustor is.

As a regulated burner, the regulations I am operating under are based on plume opacity, the color of stuff coming out my chimney - the stuff the Air Police can see from the street without a warrant.

I have made many trips outdoors in slip on winter boots to check my stack. There is a particular spot on my factory combustor probe dial where I can count on finding a clean plume when I go outdoors to look.

There probably are some installs where the plume goes clear the moment the combustor is engaged. I doubt there are more than four in all of North America. To find out if yours is one you will need either a cooperative spouse and some walkie-talkies, or a pair of slip on winter boots by your door. If you are going to do this, have a house key on your person in case you lock yourself out.

I would suggest the indoor person engage the combustor whenever, start a chronograph, and not send a heads up to the outdoor person. When the outdoor person radios in "clean plume" the indoor person can then stop the chronograph. To do this accurately the outdoor person needs to be able to discern between steam and smoke.

@MissMac is loading and timing for an active combustor. Given you are five years in with no problems I can't tell you you are doing it wrong.

The Air Police don't have warrants and don't care how your stove is set up. The EPA generated regs are based on having an observer on the sidewalk with a stop watch looking at your stack, your cold start is graded pass/ fail, no warrant required.

My fastest cold start to clean plume times are build the biggest fire I can, limit the flue gas temp to 1000 degrees with the thermostat, engage when the indicator is centered in the notch between inactive and active - and I generally find a clean plume 1-3 minutes after that.

 

[Poindexter]

Thanks for all the input guys - Really appreciate you all taking the time to help a new guy out. Under a cord so far through the stove, mainly because this thing burns so well/efficient. I'm on my second IBC tote, so somewhere between 1/3 and 2/3 cord.

Once I get the Condar Flue thermometer in and installed, I'll update with how the temps look during the normal start up routine and how they compare with the outside pipe temps I saw last night. Thinking about it more, I really do think I would have seen the outside black pipe temp go above 250* if there was a fire, but maybe the short duration limited the heat transfer? Thanks again for all the help.

Don

If you've only run less than one cord, more or less by the book, in a new BK with a working combustor, I doubt you could have accumulated enough creosote to have a chimney fire if you wanted to start one.

My infrared tire pyrometer works best with the sensor 1-3 inches from the surface to be measured. The current production medical thermometers I am seeing these days want 1 centimeter of air only between skin and sensor. No idea how far your IR gun can reach, but chimney top from the ground is a more expensive instrument than I have.

 

[Poindexter]

My sense of the membership here is the vast majority of you are not regulated burners. We have a few in the Puget Sound area, begreen and highbeam come to mind.

I think Salt Lake City area also, but I can't think of an active user from that area on this website.

If/when you are about to become an EPA regulated burner it will be all over your local news and your local facebook server will crash.

 

[Poindexter]

The only time I have heard that sound is when several years ago I was burning some maple that got wet in spots through leaks in the tarp. It was the only wood we had so I was burning it, but by the end of November I was getting that sound during start up, before closing down the air. I think this sound is from a layer of creosote that has formed inside the stovepipe that ignites under high temp. There isn't enough for a full-on chimney fire, but enough of a glaze to burn. We cleaned the chimney after that and got about a quart of soot and sote. That's after one month of burning or about 1/2 cord of wood. Normally, burning dry fir we get about 1/2-1 cup after 3 cords. After that, all damp pieces came into the house for a week before burning.

Good to know. The remainder of my stash for this year is now snow covered. You found a week indoors before burning to be adequate?

 

[bigealta]

Hey All - First time using a free standing stove and I'm not sure I'm doing everything 100% right, since as the title suggests, I think I may have had a small chimney fire tonight. I have a new BK Chinook 30.2 and I've been using it for a few weeks since finishing the install. I haven't burned much in the past week since temps in my area have been pretty moderate (Delaware has been in the 50's or higher). So tonight it's getting cold again and I loaded up the box to start the fire. Fire got going well, and was pretty hot with it hitting the "Active" zone right about 18 minutes when I closed the bypass. Manual says to keep the thermostat on high for a good fire for 20+ minutes to help burn off the creosote in the box and char the new wood, and tonight at about the 20 minute mark, I could hear something strange, which was best described on other threads here as rice-krispies running down the stove pipe. As soon as I realized what it was, or at least what it may be, I turned down the stove and the noise stopped within about 20 seconds. It was making that noise for around 90 total seconds between me hearing it, using a laser thermometer on the interior stove pipe, going outside to look at the chimney, and coming back in and to turn the stove down. The interior double wall pipe was about 230-250* exterior temp to about 8' up, then under 200* up to where it enters the ceiling box. The Chimney outside had no signs of anything wrong - No sparks, just light/white smoke that seemed normal and showed no temp increase above ambient, if the laser thermometer even works that far away.

So here is the real question - Do you think it was an actual chimney fire or am I just being paranoid?

I am seeing more creosote inside the fire box and on the glass then I was used to in my last Osburn insert, and I'm not sure if that's normal or not. I'm burning seasoned wood that is under 20%, at least on the pieces I've checked, but will check more to make sure. Wood I'm on now is a bit of a mix of species, but all hard wood. During the steady-state burn, I normally run the thermostat at around the 4:00 position and I'm very happy with the 12+hr run times and it's all the heat my house needs. Do I need to run hotter and just vent with outside air?

I know a double wall stove pipe thermostat would have been helpful in diagnosing issues, and one is on order now.

I'm just a little nervous about next time I run it on high with a new load of wood? Is there anything else I should do other make sure I watch things closely?

I don't have the equipment to clean the chimney myself at the moment, but was planning on buying and cleaning things in the spring. Should I get it cleaned/inspected by a professional sweep soon? Or even immediately before I continue use?

Thanks and sorry for all the questions. Did a lot of reading tonight but didn't see much about what happens after a small fire like this, only bigger fires and damaged equipment.

Don

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View attachment 289016

Could be some small bits of creosote falling down your stove pipe. As the flue heats up it can detach some small Clinging Pea size bits stuck to the inside of the flue. I can get this after a chimney sweep when the brush misses a couple spots.

Similar to what begreen described.

 

[MissMac]

I don't go by glowing combustor. Doesn't matter what color the combustor is.

As a regulated burner, the regulations I am operating under are based on plume opacity, the color of stuff coming out my chimney - the stuff the Air Police can see from the street without a warrant.

I have made many trips outdoors in slip on winter boots to check my stack. There is a particular spot on my factory combustor probe dial where I can count on finding a clean plume when I go outdoors to look.

There probably are some installs where the plume goes clear the moment the combustor is engaged. I doubt there are more than four in all of North America. To find out if yours is one you will need either a cooperative spouse and some walkie-talkies, or a pair of slip on winter boots by your door. If you are going to do this, have a house key on your person in case you lock yourself out.
your
I would suggest the indoor person engage the combustor whenever, start a chronograph, and not send a heads up to the outdoor person. When the outdoor person radios in "clean plume" the indoor person can then stop the chronograph. To do this accurately the outdoor person needs to be able to discern between steam and smoke.

@MissMac is loading and timing for an active combustor. Given you are five years in with no problems I can't tell you you are doing it wrong.

The Air Police don't have warrants and don't care how your stove is set up. The EPA generated regs are based on having an observer on the sidewalk with a stop watch looking at your stack, your cold start is graded pass/ fail, no warrant required.

My fastest cold start to clean plume times are build the biggest fire I can, limit the flue gas temp to 1000 degrees with the thermostat, engage when the indicator is centered in the notch between inactive and active - and I generally find a clean plume 1-3 minutes after that.

Oh, okay, so maybe I'm confusing 2 different thoughts here? @Poindexter your routine is to keep you inline with the pesky pollution police, I get that. You are adjusting your air I assume while the bypass is still open in order to keep your stack temps below 1000*F I think I read.

The part that made my head snap round was this:

ou stated, I triple checked, that you loaded hardwood at "less than 20% MC" and were able to engage your combustor in 18 minutes from what appears to have been a cold start. Can't be done safely from a cold start. If that was a cold start I will bet you US$500 cash money that your flue temp got up to near 1800 degrees F to get the combustor engaged in 18 minutes.

because I can get my cat to light off (which I believe means it's hot enough to be engaged) in 14 minutes. I never installed a flue probe, at first because I didn't think it was necessary given that it wasn't a required part of the install as per my BK manual, and also because I didn't know to do it. Later, after learning so much on this website and having a few convos with other members, I decided still not to put one in simply because I figure if I operate my stove inline with the manual, then I should be good.

So, I think you just got me curious with your comment above because you suggested that there's no way to light off a cat in 18 minutes safely.

 

[MissMac]

Thanks for all the input guys - Really appreciate you all taking the time to help a new guy out. Under a cord so far through the stove, mainly because this thing burns so well/efficient. I'm on my second IBC tote, so somewhere between 1/3 and 2/3 cord.

As an update, no smells, creosote on the roof that I could see, and I don't think any interior haze (it was dark out) happened last night. So maybe it was just the heat dumping into the stove pipe as the box temps got high quickly? Nothing was cooling down at the point I heard the noise, but without the gas temps inside the pipe, it's really hard to tell what's going on. I should have gotten that installed sooner, just for the data point if nothing else.

In the end, I guess only getting up on the roof and looking down will tell me for sure what things look like. I'm scheduling a pro to come out to clean and verify how things look once the snow melts off later this week, and I'll be more careful about the slowly turning down the stove instead of using the thermostat as a on-off switch (between high and 4:00 settings). On the hot reload this morning, everything worked as expected and at the 15 min mark as things were getting bright in the box, I started slowly turning down the heat (6:00 to 5:30 to 5:00, etc). I never really put much thought into the 20min wording in the manual, but what you put in around the EPA requirements make sense. Not a lot a lot of people around here burn full time, so it's unlikely I'll have any issues with people complaining. In reality, the only time you see smoke and smell it is at start up, and I doubt there's anyone sitting outside with a stop-watch or that even understand the newer EPA requirements/rules.

Once I get the Condar Flue thermometer in and installed, I'll update with how the temps look during the normal start up routine and how they compare with the outside pipe temps I saw last night. Thinking about it more, I really do think I would have seen the outside black pipe temp go above 250* if there was a fire, but maybe the short duration limited the heat transfer? Thanks again for all the help.

Don

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I think you'll set your mind at ease having a sweep come out and run the brush through and tell you how things are looking thus far. I was similarly nervous my first year because I didn't know what to expect from my set-up and I was new to burning in a wood stove. I got up on my roof one month in and took a peak so that I could actually see how things looked. I went back up a month later just to peek again, and decided to run the brush through (which ended up being entirely unnecessary but gave me piece of mind). I did a mid-season sweep again the next year (again, wasn't actually necessary), but then went to sweeping once per year the last 2 years with no problem at all, and this is now my routine. It's good to be cautious and deliberate and diligent learning your new system and how it performs I think. After all, you are making a fire in the middle of your house, so to me being appropriately cautious and curious when you're first starting out is a good thing and will give you piece of mind moving forward.

Let us know what the sweep reports. As others have said though, I think if your wood is as dry as you say and you've been running your stove as per the manual and your set-up is good, then there shouldn't be any issues with what's in your stack. Only one way to know for sure though!

 

[jdonna]

I don't go by glowing combustor. Doesn't matter what color the combustor is.

As a regulated burner, the regulations I am operating under are based on plume opacity, the color of stuff coming out my chimney - the stuff the Air Police can see from the street without a warrant.

I have made many trips outdoors in slip on winter boots to check my stack. There is a particular spot on my factory combustor probe dial where I can count on finding a clean plume when I go outdoors to look.

There probably are some installs where the plume goes clear the moment the combustor is engaged. I doubt there are more than four in all of North America. To find out if yours is one you will need either a cooperative spouse and some walkie-talkies, or a pair of slip on winter boots by your door. If you are going to do this, have a house key on your person in case you lock yourself out.

I would suggest the indoor person engage the combustor whenever, start a chronograph, and not send a heads up to the outdoor person. When the outdoor person radios in "clean plume" the indoor person can then stop the chronograph. To do this accurately the outdoor person needs to be able to discern between steam and smoke.

@MissMac is loading and timing for an active combustor. Given you are five years in with no problems I can't tell you you are doing it wrong.

The Air Police don't have warrants and don't care how your stove is set up. The EPA generated regs are based on having an observer on the sidewalk with a stop watch looking at your stack, your cold start is graded pass/ fail, no warrant required.

My fastest cold start to clean plume times are build the biggest fire I can, limit the flue gas temp to 1000 degrees with the thermostat, engage when the indicator is centered in the notch between inactive and active - and I generally find a clean plume 1-3 minutes after that.

Kuddos to this post.

I think this is great advice for anyone really. Even though we are not in a regulated area and have no neighbors nearby to bother, we do care what comes out of our stack.

1. Keeping your chimney cleaner.
2. Watching a probe thermometer when bypassed, you will be amazed how fast you can overheat your stack with dry wood and a strong draft. I never leave the stove for a minute when its in bypass on a new load.
3. Smoke and particulate do settle out of your plume and there will be times it will infiltrate your house.
4 . Someone driving by might think you are having a chimney fire if you are belching a huge plume of smoke out of your stack.

We have a neighbor 4 miles south of us with a OWB and I can hardly stand to be outside if conditions are right and a south wind is blowing. It's beyond me how they can live with that plume of smoke around their property!

 

[stoveliker]

Oh, okay, so maybe I'm confusing 2 different thoughts here? @Poindexter your routine is to keep you inline with the pesky pollution police, I get that. You are adjusting your air I assume while the bypass is still open in order to keep your stack temps below 1000*F I think I read.

The part that made my head snap round was this:

because I can get my cat to light off (which I believe means it's hot enough to be engaged) in 14 minutes. I never installed a flue probe, at first because I didn't think it was necessary given that it wasn't a required part of the install as per my BK manual, and also because I didn't know to do it. Later, after learning so much on this website and having a few convos with other members, I decided still not to put one in simply because I figure if I operate my stove inline with the manual, then I should be good.

So, I think you just got me curious with your comment above because you suggested that there's no way to light off a cat in 18 minutes safely.

I have a flue probe (since this year). I get the cat up to temp below 20 mins with my (slow) flue probe not at 1000 F.

I think it depends a lot on the set up (I do have a tall chimney, but a 2'-3' horizontal run, and it's not as cold as in AK - but I have not measured my draft).

Blanket statements about what can't be done should not be made imo. One (aberrant?) case can prove such a blanket statement wrong...

 

[MissMac]

Kuddos to this post.

I think this is great advice for anyone really. Even though we are not in a regulated area and have no neighbors nearby to bother, we do care what comes out of our stack.

1. Keeping your chimney cleaner.
2. Watching a probe thermometer when bypassed, you will be amazed how fast you can overheat your stack with dry wood and a strong draft. I never leave the stove for a minute when its in bypass on a new load.
3. Smoke and particulate do settle out of your plume and there will be times it will infiltrate your house.
4 . Someone driving by might think you are having a chimney fire if you are belching a huge plume of smoke out of your stack.

We have a neighbor 4 miles south of us with a OWB and I can hardly stand to be outside if conditions are right and a south wind is blowing. It's beyond me how they can live with that plume of smoke around their property!

Great points you bring up here. I'm not interested in smoking out my neighbours or creating excessive pollution which is part of the reason I bought the BK stove.

I too never leave my stove when it is in bypass. But I'm also not monitoring the stack temps as previously mentioned. I'm just there 'in case' something seems to be off or amiss, which so far it hasn't been to my visible senses. And also so that I don't ever put myself in a situation where I forget about the bypass being open and then let the stove run away.

One thing worth noting though is that in the BK manual it doesn't say anything about monitoring your stack temps when in bypass mode and adjusting the air accordingly. It's simply 'set it on full throttle, bypass open, wait for cat probe to show active, engage cat by closing bypass'.

I would think that the vast majority of BK stove users are doing just that, without modifying based on stack temp observations. Just a thought in response to your comment about watching your probe.

 

[stoveliker]

Yes. That is the trust in the Tstat which should contain things to allowable parameters (if installed properly).

As with heating modes (I have wood, oil, minisplit), I prefer not to rely on one with measuring (and controlling) what's happening with that fire in a box in my home.

I agree about small pieces of creosote dislodging (from expanding pipe) and falling as an explanation for the sounds by the OP.

 

[Poindexter]

So, I think you just got me curious with your comment above because you suggested that there's no way to light off a cat in 18 minutes safely.

I don't think it can be done safely with a typical average install. One thing to keep in mind is registered users here are among the most conscientious burners in North America. BKVP says so several times annually and mentioned "us" as a group in particularly glowing terms just in the last week or two.

From previous F2F conversations with Chris over the years, the typical burner, who isn't registered here, is running fuel at 20-22% MC, and all the stoves from all the manufacturers are designed around that finding. When we start loading fuel at 18-16-14 % we are pushing the design envelope already.

So let us just ask Chris and get it over with. @BKVP, loading fuel at 15-20% MC on a typical/ average chimney how fast can we reasonably expect to consistently get to active combustor without overheating our chimney pipes?

 

[Poindexter]

Blanket statements about what can't be done should not be made imo. One (aberrant?) case can prove such a blanket statement wrong...

I have been fooling with this problem for coming up on seven years now.

https://www.hearth.com/talk/threads/regulated-burners-cold-start-tips.140279/

I have no reason to think my draft is unusually weak or strong. With house guests that needed to remain fully clothed I was able to get a 36 hour burn out of my A30.0 with outdoor ambients in the +20 to +30 dF range. It remains my personal long burn record with an active cat, but the house was not warm enough (given the fully clothed guests staying over) for my wife to be in the wardrobe I desire. At -30dF and colder I can burn down a box full of spruce in 4 hours. Everyone here will have better/ stronger draft at -30 dF than they do at +30dF. I conclude my draft is average/ typical and have intentionally not commented on any of the damper conversations I can recall.

The EPA reg requiring regulated burners to get from cold iron to clean plume in 20 minutes should not be on the books because it is not safely attainable by average burners using average fuel in average installs. I don't know any above average burners with above average fuel that can do it, not one. Period. See you in court.

Please keep in mind, first lit kindling to engaged combustor is not the same interval as first visible plume of smoke at opacity of 50% to clean plume. There have been several folks in the last few years mucking about with engaging their combustors early. The general idea is "I know my stove, I know my probe runs about ten minutes behind reality, I know my fuel, therefore I have been engaging my combustor 10 minutes before it would get to the active zone and I haven't broken anything yet." But none of them, zero people, have been able to photographically document that process got them to clean plume any faster.

I will quietly admit I have fooled around with engaging my combustor early back in Feb 2015 and I found no consistent measurable improvement in total time to clean plume.

If you can think of something I haven't tried I am all ears, but I would very much prefer to get the bad rule off the books or ammended.