# education in chimney fires



## Carl Webber (Nov 30, 2014)

I have a Tarm OT-50 and because it is not a gassification boiler it produces a descent amount of creosote. I've heard from most people that if you have a non gassification boiler it is inevitable that you will have a chimney fire at some point. I've been doing some reading about chimney fires and i have some questions that i'm hoping I can get answered so I can better understand how to run my boiler and avoid a chimney fire as much as possible.

1. What actually causes a chimney fire? Is it heat from overfiring the boiler or is it sparks that make their way up the chimney and get stuck in the creosote?

2. Can I still have a chimney fire if I don't overfire my boiler and i try to run it in the optimal temp range as much as possible?

3. I realize that it is the creosote that burns. I have noticed that there are two different forms. One is this black tar like sticky stuff that is just plain nasty. The other kind is puffy and crusty and flakes off easily. I've noticed that if you apply heat to the the black tarry shiny stuff it puffs up and becomes brittle and flakes off. Are both of these present in my chimney? If the sticky stuff is present in the chimney how am i supposed to remove it because that stuff does not just come off with a brush? How are both created? Is the sticky stuff what is created if you don't run your boiler up to the optimal burn temp and then when it gets to temp the sticky stuff burns off and it puffs up and blocks the chimney? The crusty puffy stuff doesn't appear to burn. I've put a torch to it and all it does is glow. If this stuff builds up in my chimney do I still have to worry about a chimney fire, or is the main concern the reduced draft and the plugged chimney?

4. I have a hard time seeing what my chimney looks like from the bottom, even with a light and a mirror in the clean out. Can i get an idea of what my chimney looks like by looking through my boiler and into the connecting stove pipe, or will the stove pipe build up creosote faster than the chimney? How much faster does the single wall stove pipe build up creosote compared to the chimney?

5. If i have a chimney fire, i know i need to close everything up tight to cut off the draft to the chimney. Does this mean I also need to prop shut the barometric damper too? Is propping it shut good enough, or should i cover the entire opening with something to make sure the draft is completely blocked?

6. From researching on the internet i found something called Chimfex. It claims it starves out the chimney fire in as little as 22 seconds. I found them at a local hardware store and bought one for $25. Does anyone have any other advise or suggestions for extinguishing a chimney fire? I know i've heard things like throwing chain down the chimney or spraying water down it, but both of those either destroy the house or the chimney. I'm looking for simple things that work but won't harm the chimney or house if thats possible.

7. I've noticed what seems to be quite a bit of build up of creosote in the boiler. I've only ever run a wood stove. The amount of creosote seems alarming to me, but i don't really know what i'm looking at. How much creosote is ok inside the boiler and how much is too much? Can this creosote catch fire just like it does in the chimney or do i not need to worry about that? Do i need to scrub the inside of the boiler just like i do the chimney? A lot of the stuff in the boiler is black and shiny and sticky, if it is needed, how do i remove that stuff?


Any other information people can give me would be much appreciated.


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## DoubleB (Nov 30, 2014)

I look forward to hearing answers to your questions.  Regarding #6, I've received advice on this forum to throw a wet towel in the firebox, evidently to displace the oxygen in the chimney with steam, not to mention cool down the firebox.  

But, like you I bought a similar product as chimfex and have it at the ready.


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## mike van (Nov 30, 2014)

My views from a lifetime of wood burning Carl - #1 I believe sparks & flame ignite the creosote and start the show.    #2, Yes, eventually the creosote will continue to build down towards the fire and get lit.  #3 The hard glassy creosote is impossible to remove, as long as your still burning, it is accumulating.  Time and weather will loosen it, but I mean years when I say time.  #4, not sure with your setup. My Harman had so plugged my 8" masonry chimney that one night smoke was coming from the seams of the 4' of stovepipe I had, it could not get up the chimney.   #5, it will certainly help to close all air sources, including the baro. damper, but it won't put the fire out.  #6  the best chimney fire extinguisher  I found was 5 pounds of salt, dumped down the chimney from the top. Put one out in minutes.  #7 creosote inside the boiler will burn off, not a big problem.  What it does show though, is your fires are way too dampened down [i'm figuring dry wood]     The best cure I found for my 16 years of chimney fires was junking the Harman & buying a Garn.  If your Tarm has an auto draft door as my Harman did, it is a recipe for creosote, there is no way around it.  Burning a hot fire, and the heat going into storage is the best fix.  Forgot to add -  I make syrup, 25 to 30 gals a year, not huge, 100 taps.  I burn nothing but pine, spruce, hemlock in my evaporator. Really dry wood, burnt wide open as hot as it'll go. There is no creosote in that chimney, it's black with carbon, but no creosote.  Point being, as soon as you start snuffing off a fire, you start having problems. My opinion.


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## Carl Webber (Nov 30, 2014)

I have read the Tarm manual and it said pretty much the same thing about the fires. The best bet is to burn hot. If you can't burn hot then don't burn and use the oil. Tarm recommends using the oil in the spring and fall and only use wood when its cold. Hopefully in the next year or two I will have the money and resources to put in some storage. For now i have to deal with what i've got.


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## Corey (Dec 1, 2014)

With proper cleaning, I would not think a chimney fire is 'inevitable' at all.  With a well insulated flue and decent burning techniques (ie dry wood and minimal smoke) all you will generally see is the light fluffy creosote which is very easy to clean away.  If you burn wet wood and let it smoulder a lot, you could see more of the tar like creosote which is harder to clean away.


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## jebatty (Dec 1, 2014)

> ... because it is not a gassification boiler it produces a descent amount of creosote. I've heard from most people that if you have a non gassification boiler it is inevitable that you will have a chimney fire at some point.


 I know of no reason why these statements are  inevitably true.

Whether or not a person has a gasification boiler has nothing to do with producing creosote which would cause a chimney fire, but has everything to do with:  1) burning wood not well seasoned, 2) letting the fire smolder and not burning a hot fire, 3) failing to regularly brush/clean the chimney, 4) and if a boiler failing to have boiler return water temperature protection. And I cannot believe that, no matter what wood burning appliance you have, if you burn well seasoned wood, burn a hot fire without smoldering, and brush/clean the chimney regularly, (and return water protection if a boiler) you will inevitably have a chimney fire. In my experience of 23 years of wood burning with the same basic wood stove in our living room and then also since 2007 with a Tarm Solo Plus 40 gasification boilers in my shop, following the proper burning rules has resulted in nothing more than fine dust in the Class A chimney after each season of burning.

I burn primarily, in this order, pine, aspen, and then mixed oak, birch, maple, miscellaneous. Regardless of the species of wood, only fine dust in the chimney. And I also must state that, based on comments in this forum, some of those with gasification boilers who have not followed the burning rules have seen creosote dripping out of their boilers.

Pay attention to what and how your burn, follow the rules without exception. Chimney fires do not ever need to be inevitable.


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## brant2000 (Dec 1, 2014)

Carl Webber said:


> 4. I have a hard time seeing what my chimney looks like from the bottom, even with a light and a mirror in the clean out.



One thing that I've found to work really well, is to just use a cameraphone with the flash on to get a good look up your chimney.  I just hold mine in the cleanout door and snap a few pics.


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## F4jock (Dec 1, 2014)

I spent twelve years in the fire service. Those years, as well as having an early wood stove. taught me as follows: You do NOT want a chimney fire and they are NOT inevitable. Burn only well seasoned, dry wood and burn hot. If you can't burn hot all the time do so at least twice a week for an hour. Clean your chimney early and often; before season, halfway through and toward the end. Keep a chimney flare on had just in case. I've seen chimney fires destroy houses. I repeat, you do NOT want one. There are good tips in this thread. Use them!


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## surefire (Dec 1, 2014)

I've been heating for over twenty years with a wood-fired forced-air furnace, and I've never had a chimney fire.  My wood is seasoned for at least three years.  I clean my chimney every month or so and inspect it with a flashlight more often than that.  The furnace intake damper is controlled by the main floor thermostat but the furnace also gets run a lot full-out.  Sometimes there's a bit of black soot on the snow around the house... a good roaring fire shakes that flaky stuff free from the chimney I guess.  The natural draft is pretty good at -31*C !


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## Eric Johnson (Dec 1, 2014)

Before I had a gasifier I had a conventional wood-fired boiler. I got into a routine of cleaning my chimney once a week--whether it needed it or not. Sometimes it did and sometimes it didn't. I had a stainless liner accessible from the basement, so frequent cleanings were not all that difficult to accomplish. I did have one serious chimney fire and while it stayed in the liner, it did scare the heck out of me. Not much I could do but wait for it to burn out. I tried running a steel brush and fiberglass rods up in an attempt to knock the burning creosote down, but only managed to destroy both.

Cutting off as much air as you can is your best bet. For that reason, I'd serious consider either sealing off or replacing the barometric damper with a solid piece of pipe. Hook it back up when you switch back to oil. You shouldn't have that thing with a wood burning appliance in any event, I don't think.

The presence of creosote in the firebox doesn't really tell you much about the situation in the chimney. As brant suggests, stick a GoPro or smart phone or small digital camera in there for a look-see. Or, just run a brush up it and find out. The nice thing about a video is that you might be able to see any cracks or other flaws in your chimney liner (assuming it's lined and lined with ceramic tile). If it's not lined, don't even think about burning any more wood until you get a liner in there. If it's got some serious cracks or other problems, best to shove a stainless liner in there as well.

Good luck. You'll know if it lights off. Sounds just like a jet plane flying over your house.


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## Carl Webber (Dec 1, 2014)

At my parents house when i was younger they had a chimney fire so i am familiar with what it sounds like. The big difference is that they have a vermont castings wood stove and their house is only 1 story so the distance from the thimble in the chimney to the top is probably only about 5 or 6 feet. The one or two times they had a chimney fire all they did was close everything up tight and the fire burned out in about 5 minutes. In my case the boiler is in the basement and the chimney is at least 20 feet tall. That is a lot more creosote and a lot more heat that will be produced. It is also more complicated in my situation because i have a boiler and not a wood stove and it is a wood oil combo. I want to be as cautious as possible, but i also don't want to go as far as being paranoid and create a lot of extra work for myself. That being said, it sounds like it would be difficult for me to over do it as far as prevention goes, especially if some of you are cleaning your chimneys once a week. The big thing I've noticed about my boiler is that it heats up a lot faster with the wood than with the oil. I also have to be careful because if i get too hot of a fire going and i get a good bed of coals the boiler can't absorb all that extra heat so it ends up dumping the heat. The best thing I've found so far is I wait till the boiler is down to about 155, just before the oil kicks in. Then split my wood up pretty small so each piece is no more than 3 or 4 inches in diameter and i light a good fire. It burns hot and fast and by the time the boiler is back up to temp there isn't much but a good bed of coals left. By that time i don't have to worry too much about creosote because any moisture is gone. Then it'll be about another 2 or 3 hours before i light another fire. On colder days like we just had here a couple days ago when it was about 15 during the day I can let the fire burn down to just coals and then it will sit for about an hour or so and there will still be some coals when i go to start the next fire to heat the boiler back up. I'm just a little paranoid because i know the boiler can produce a dangerous amount of creosote and the last thing i want to do is accidentally burn down my house.


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## Eric Johnson (Dec 1, 2014)

What kind of chimney do you have, and what shape is it in? That's probably the most important factor, since a good chimney is unlikely to fail with the first chimney fire. One thing you might consider is putting a damper in your exhaust pipe, if it doesn't have one already. My old chimney was probably 40 feet from the outlet from the basement to the top of the chimney, and it had so much draft that I needed to control it with a manual damper. Along with keeping the thing from overheating, the damper also kept big flames out of the chimney. That's the best way to torch one off--let the flames crawl up the liner and ignite the creosote. Or, let a burning piece of paper get in there. Damping it down wrong can also generate more creosote, so you need to watch it to see how much dampening you need. On a -30 night with my other system, I'd completely close the damper. The draft getting through the holes in the damper plate provided enough draft. Your mileage will vary.


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## Fred61 (Dec 1, 2014)

Carl Webber said:


> It burns hot and fast and by the time the boiler is back up to temp there isn't much but a good bed of coals left. By that time i don't have to worry too much about creosote because any moisture is gone


Moisture is a byproduct of combustion regardless of the fuel. Oil, propane, wood etc. That's why you see all chimneys emitting steam on a cold morning when people's heaters are running.


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## Carl Webber (Dec 1, 2014)

I do realize that moisture is always there, but if the fire burns hot a clean doesn't it create less creosote because the moisture makes it all the way up the chimney instead of condensing on the inside of the chimney?


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## Fred61 (Dec 1, 2014)

Yep!


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## Carl Webber (Dec 1, 2014)

i have a brick chimney with 8 inch modular flue tiles. Until i put in this boiler it only had the exhaust from my oil boiler going up it. The last time i checked it, it was completely clean. The chimney was built in 1986 when the house was built. The chimney is on the gable end of the house so 3 sides of it are exposed. There is also a fireplace flue in the chimney. The fireplace does not get use on a regular basis. We only use it once in a while when its really cold because it only heats the living room and it messes with the thermostat so the rest of the house will get cold. For the most part the chimney is in good shape. The chimney was not capped until 2011. The first year that we had the house i noticed a lot of moisture coming down into the fireplace. I also noticed when we had a fire in the fireplace that i would get a back-draft and a puff of smoke into the house when the wind blew. I capped both of the flues in the chimney and haven't seen any problem with moisture or back-draft since. The last time i looked at the inside of the chimney everything looked solid and it looked clean.


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## Fred61 (Dec 1, 2014)

Sounds good! Just remember an outside chimney cools the exhaust faster so be sure to stay on top of your maintenance. I had two 34 foot tall chimneys, one on each end of my previous colonial and I had the mason insulate the flue tiles from the brick with 2 inches of vermiculite. Worked good!


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## Carl Webber (Dec 1, 2014)

The only thing i've noticed about my setup is that the draft seems a little slow. I think it might be that the basement is too tight. I think i might need to set something up to allow more air into the basement so there is more positive pressure in the basement. I noticed the other day when i had the bulkhead open that the fire was burning pretty good even with the damper mostly shut, but when i shut the bulkhead the fire died down some. It appears to me like the boiler might burn more efficiently with a better supply of combustion air. 

My boiler (Tarm OT-50) has a flap in the top of it that can be adjusted. Straight up and down and it blocks off the top of the firebox so the flue gasses get sucked back through the hot coals and across some heat exchange tubes before going out the chimney. If i try to run it this way, even with the draft wide open my stack temps only reach about 150 on the outside, (I think that means about 300 on the inside). That isn't hot enough. So i moved the baffle at the top of the firebox so its at about 45 degrees. This allows more heat up the chimney and wastes some of the energy in the flue gasses but when running like this the flue temps get up to between 350 and 400 on the outside of my stovepipe (I think that would mean between 700 and 800 on the inside). I also noticed that if i ran with that baffle straight up and down i created a lot more creosote in the firebox. It was enough so i could see it dripping down the walls and it was the nasty shiny sticky stuff. After adjusting the baffle to a 45 everything seems to burn much cleaner and i only see a little bit of dry crusty stuff accumulating and it flakes off. on its own. 

I was thinking that if i let more air into the basement it would allow for a greater draft and i might be able to run the boiler the way it was intended with the baffle straight but and down so i can burn the flue gasses too.


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## Carl Webber (Dec 1, 2014)

Fred61 said:


> Sounds good! Just remember an outside chimney cools the exhaust faster so be sure to stay on top of your maintenance. I had two 34 foot tall chimneys, one on each end of my previous colonial and I had the mason insulate the flue tiles from the brick with 2 inches of vermiculite. Worked good!



How did the mason do that? Was it expensive? Did it require rebuilding the chimney?


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## maple1 (Dec 1, 2014)

I am on the opposite side of thought posted above re. barometric dampers.

I think one should be there.

They limit draft the appliance sees - and during the 17 years of using my old boiler, the primary potential source of a chimney fire igniting was from wind gusts sucking the fire out of the firebox up into the pipe & chimney. I'm on an open hilltop so maybe more vulnerable than others - but it was risky business if my damper happened to stick shut. Plus, if it is installed in the right place, it can also serve as a very handy inspection & cleanout point. Mine was (still is I guess) just before the flue T - I could peek in at the flue & see what was there, scrape/knock down/vacuum out the fuzzy stuff. Now I use it as a place to stick a vacuum hose in with sump pump hose stuck on the end to vacuum ash out. Just have to flip it open and you're in.

Keep in mind though that inspection needs to be regular & often - that point will likely be the place that sees the most build up. But it will be easy to get to & clean out.


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## Fred61 (Dec 1, 2014)

Carl Webber said:


> How did the mason do that? Was it expensive? Did it require rebuilding the chimney?


Built the whole place NEW. Yes, it was expensive


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## Carl Webber (Dec 1, 2014)

maple1 said:


> I am on the opposite side of thought posted above re. barometric dampers.
> 
> I think one should be there.
> 
> ...




Ok, since someone brought this up I have some questions. I have heard that the damper puts cold air into the flue so it cools things down and this isn't always good for a wood burning setup. The guy that put in my system put my damper about 6 inches behind the boiler. Then there is about 2 feet to the chimney thimble. Is this a good setup, or should the barometric damper be further up the pipe?

I have a thermometer on the stovepipe so I have some idea how well i'm burning. It is just one that sticks on the outside because I have single wall pipe. I put it on the elbow right before it goes into the chimney. This is about 2 feet above the barometric damper. Is that a good place for it? Where it is now, when the fire is burning good i can get readings of up to 450 from the outside of the stovepipe. According to the thermometer that is in the optimal burning range. But of course that doesn't take into account the added cool air from the damper. So really the fire is burning hotter but the damper is cooling it down some. Should i move the Damper and then put the thermometer below the damper or is it better the way it is set up now? Is one way better or worse as far as creosote goes?

Currently I've been burning for about 2 weeks and There is a good layer of creosote on the inside of the stovepipe and the other day i noticed it had dripped down the backside of the damper and it was stuck. The stuff in the stovepipe is crusty, but the stuff on the backside of the damper is that nasty black tarry stuff. I'm sure that is because the damper door always has cool air going across it and cooling it way down.


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## jebatty (Dec 2, 2014)

While it won't eliminate the chimney fire threat or other problems from burning less than dry wood or from poor burning practices, there is a lot of benefit from using Class A, stainless, double wall, insulated chimney pipe. The most important benefit is a high level of protection of the house structure from catching on fire as a result of a chimney fire, and then because of the insulation the flue gases going up the chimney stay hot and condensation in the chimney usually is eliminated. Other benefits include ease of cleaning, easy to install, 2" clearance to combustibles.

I installed my own Class A chimney back in 1990, never cleaned more than once/year at the end of the burning season, and still looks almost shiny new on the inside after its annual brushing. What amazed me was that the outside the Class A chimney pipe was barely warm to the touch while the inside center flue gas flow easily could have temperatures up to 800F or more.

But I have to say again, if creosote is collecting in the chimney, then almost certainly the wood is not well seasoned, and/or the fire is smoldering and/or hot fires are not being burned. Wood needs to be dry and need to be burned at a very high level of combustion to burn efficiently, and an efficient burn goes a very long way to preventing the formation of creosote and the potential of a chimney fire.


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## Carl Webber (Dec 2, 2014)

I have to agree with you about the burning. As this is my first wood boiler it has been a learning experience for both me and my girlfriend. The first couple fires I had created a lot of creosote and made me a little nervous. Then I discovered that if i changed the position of the baffle at the top of the firebox i had a lot better combustion. Then beyond that I discovered if i split my wood down to pieces that were no more than 4 inches in diameter the fire would burn hotter faster. Then I figured out that the boiler held enough heat that I didn't need to keep a fire going all the time. I could set a good strong fire once every 2 or 3 hours. I also found that at night it worked out best if I threw in a couple sticks of wood to make the fire last a little longer, but not too much. Then I'll set my alarm for about 4 hours later and I'll get up and restart the fire and have a good strong burn and i'll thrown in a larger stick or two of wood to make it last till I get up. Doing this way I'm having hotter fires and there isn't as much smoldering because I'm not trying to make the fire last all night.  After all this I'm not seeing too much new creosote. I am seeing a little bit of ash sticking to the old glassy sticky stuff, and I am seeing some of that stuff burn off, but not so much new creosote. The first day or two really made a mess of thing though. The first couple fires I had the inside of the stovepipe and the boiler were all glassy and sticky and you could see the creosote dripping down the walls of the firebox. A wood boiler is definitely much different than a wood stove because of the water and the cool walls.


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## mike van (Dec 2, 2014)

Carl, just my 2 cents again. Its only Dec 2nd, you are in for a long winter if you have to light a fire every 2 to3 hours with wood split smaller than 4'" You need to let it go out, pull the pipe, and see how bad that 8" flue really is.  Do you have a chimney brush? See how hard it is to push up  & down the flue - A really bad chimney fire will crack that chimney & spread to the framing of the house.  Small hot fires every  few hours just  let the chimney cool off....


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## mike van (Dec 2, 2014)

Carl, just my 2 cents again. Its only Dec 2nd, you are in for a long winter if you have to light a fire every 2 to3 hours with wood split smaller than 4'" You need to let it go out, pull the pipe, and see how bad that 8" flue really is.  Do you have a chimney brush? See how hard it is to push up  & down the flue - A really bad chimney fire will crack that chimney & spread to the framing of the house.  Small hot fires every  few hours just  let the chimney cool off in between them....starting the problem all over.  Do you have the oil  furnace in that flue too?  You said before it used to be?  If not, why is there a baro. damper?  If you were putting an air tite stove in that flue [basically what your wood boiler is] you wouldn't have a baro. damper.  Someone else correct me, but I think it cuts down on draft through the fire, lets cold air up the chimney, not helping your problem.  That pipe thermometer should be a lot hotter right behind the unit.  As you get farther up the chimney, it drops like a rock. I wish it was easy, but I know what I went through for 16 years, I don't believe there is an easy "fix" for what you have.


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## peakbagger (Dec 2, 2014)

I have a non gasification boiler and my neighbor had a non gasification boiler. He has multiple chimney fires despite cleaning his chimney monthly in the winter. He got to the point that he cracked his masonry liner and then burned up an insulated liner. I have cleaned my chimney twice in 25 years as it doesn't need it.

 What is the difference? He burns wood that at best is 6 months old. He runs the boiler continuously allowing the damper to operate when there is no heat demand. He has a exterior masonry chimney. I have an interior one.  I added 550 gallons of unpressurized water storage 3 years ago and prior to that only ran the boiler when there was heat demand and watched the fuel so the damper rarely closed. The vast majority of gasification boilers have storage and most companies will not guarantee units that don't have it. My goal is to season my wood 2 years but the reality is that I have burnt wood that as cut in March and burned In December. I use more wood when the wood is not super dry but I have not seen an increase in creosote.

To me the biggest thing you can do is add storage. Even if you upgrade to a gasifier in the future, the tank will still be needed. That's what I plan to do. If you don't have storage, you have to accept significant temperature swings in the house and match your fuel load so that the boiler always stays below the temperature where the damper closes. This effectively limits you to only very cold weather.


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## maple1 (Dec 2, 2014)

Carl Webber said:


> Ok, since someone brought this up I have some questions. I have heard that the damper puts cold air into the flue so it cools things down and this isn't always good for a wood burning setup. The guy that put in my system put my damper about 6 inches behind the boiler. Then there is about 2 feet to the chimney thimble. Is this a good setup, or should the barometric damper be further up the pipe?
> 
> I have a thermometer on the stovepipe so I have some idea how well i'm burning. It is just one that sticks on the outside because I have single wall pipe. I put it on the elbow right before it goes into the chimney. This is about 2 feet above the barometric damper. Is that a good place for it? Where it is now, when the fire is burning good i can get readings of up to 450 from the outside of the stovepipe. According to the thermometer that is in the optimal burning range. But of course that doesn't take into account the added cool air from the damper. So really the fire is burning hotter but the damper is cooling it down some. Should i move the Damper and then put the thermometer below the damper or is it better the way it is set up now? Is one way better or worse as far as creosote goes?


 
Just speaking from experience - but IMO anyone burning with a non-gassifying boiler will get creosote. You can limit it somewhat with procedures - but you will in no way eliminate it. And not having a barometric damper will not eliminate it - and again from my experience, not having a baro can let a chimney fire sneak up on you. You could have a week of calm weather during which your chimney quietly builds up creosote, then an overnight storm comes up where a big wind gust goes across the top of your chimney just after your fire door damper opens up way down below and wham your firebox flames get sucked up to meet the creosote and you've got excitement happening in a hurry.

Constant monitoring of creosote buildup, and getting a regular chimney cleaning regimen in place (you will need to sweep AT THE VERY LEAST once in the middle of winter) is a necessity. Do what you can to make that easier. For me, having the baro where it was made it easier. Even if it accumulated more creosote just downstream from it or around it. You won't avoid cleaning or eliminate buildup by not having a baro. And I also got a routine sorted where I could pull down my stove pipe between the boiler & chimney a bit easier (it was still a royal pain though).

On the temp guage, those magnetic thermometers aren't accurate for starters. I still have my old magnetic one stuck on my pipe right beside my new probe one. The magnetic one reads 100c less than the probe when burning. So keep in mind that temps inside the pipe are a lot hotter than what that magnetic guage is saying. It should be on the pipe between the boiler & barometric damper. And I liked having the barometric damper as close to the chimney as I could get it - it moves that point of slightly increased creosote accumulation further away from the boiler, and also provides for a very handy easy access point (although a small one) to the bottom of the chimney for inspection & help in cleaning.

All wood burning appliances (as far as I know) have a chimney draft specification. I don't know how that could be consistently met without the use of a barometric damper. Some use a key damper to limit draft but those have issues too and are far from consistent.


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## bholler (Dec 2, 2014)

maple1 said:


> All wood burning appliances (as far as I know) have a chimney draft specification. I don't know how that could be consistently met without the use of a barometric damper. Some use a key damper to limit draft but those have issues too and are far from consistent.


No most wood appliances have a minimum draft spec.  And most do not need and do not work well with baro dampers.  I know some furnace and boiler makers call for them but they absolutely increase creosote buildup greatly and if using one can be avoided at all it should be in my opinion.  Honestly the only reason for needing one is laziness on the stove manufacturers part in that it means they don't need to allow for varying draft which makes designing a stove much easier but not near as good.  I know i will probably get slammed for that opinion on this board but that is how i feel sorry.   And as far as lack of a baro making more risk of fire that may be true but if you have a fire with a baro in it will probably be much worse than it would be without one because of the increased buildup from it and because of the unlimited air supplied to the fire


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## Whitepine2 (Dec 2, 2014)

Before the outside boiler fires were often,what I found is a dry extinguisher at the bottom of chimney
would put out fire as quick as anything and not do any damage.THE DRAFT JUST PULLS THE POWDER UP PUTTING THE FIRE OUT.


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## Carl Webber (Dec 2, 2014)

mike van said:


> Carl, just my 2 cents again. Its only Dec 2nd, you are in for a long winter if you have to light a fire every 2 to3 hours with wood split smaller than 4'" You need to let it go out, pull the pipe, and see how bad that 8" flue really is.  Do you have a chimney brush? See how hard it is to push up  & down the flue - A really bad chimney fire will crack that chimney & spread to the framing of the house.  Small hot fires every  few hours just  let the chimney cool off in between them....starting the problem all over.  Do you have the oil  furnace in that flue too?  You said before it used to be?  If not, why is there a baro. damper?  If you were putting an air tite stove in that flue [basically what your wood boiler is] you wouldn't have a baro. damper.  Someone else correct me, but I think it cuts down on draft through the fire, lets cold air up the chimney, not helping your problem.  That pipe thermometer should be a lot hotter right behind the unit.  As you get farther up the chimney, it drops like a rock. I wish it was easy, but I know what I went through for 16 years, I don't believe there is an easy "fix" for what you have.



My boiler is a Tarm OT-50, it is a dual fuel boiler. It has wood on one side and oil for backup on the other. I had to go this route because I only have one flue from my chimney that goes into the basement and my hot water is run from my boiler so I need it during the summer too. I plan to use wood during the winter and oil for the summer months or any time we are gone for an extended period of time. For this reason I have a barometric damper. Right now I have my stovepipe thermometer about 18 inches above the damper and i'm still seeing temps of 400 on the outside. What i'm wondering is if this is good or not? I realize that no matter what i'm going to create some creosote. What i'm trying to figure out is how to tell when i'm running the boiler at an optimum burn. I do understand that I need to keep an eye on my chimney, but I can't be taking the stovepipe off every five minutes to see what things look like. I'm trying to understand my setup so that I know when I am burning properly and when I am just pumping the chimney full of creosote. I should be able to tell that based on how the fire burns and my stack temps.

Is it better to have hot burning fires once every 2 or 3 hours or to put a stick of wood on the fire every half hour and let it burn really slow? Either way the flue isn't seeing the temps it needs consistently. If I keep a small fire burning the thermometer reads about 175 or 200. If I burn hot and then let things slow in between the thermometer will read 400 or more for 20 to 30 minutes before it starts to cool. By the time I start a new fire The stack has cooled to room temperature. In my opinion I thought it was better to burn hot for half an hour every couple hours then to burn slow all the time.


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## Carl Webber (Dec 2, 2014)

maple1 said:


> On the temp guage, those magnetic thermometers aren't accurate for starters. I still have my old magnetic one stuck on my pipe right beside my new probe one. The magnetic one reads 100c less than the probe when burning. So keep in mind that temps inside the pipe are a lot hotter than what that magnetic guage is saying. It should be on the pipe between the boiler & barometric damper. And I liked having the barometric damper as close to the chimney as I could get it - it moves that point of slightly increased creosote accumulation further away from the boiler, and also provides for a very handy easy access point (although a small one) to the bottom of the chimney for inspection & help in cleaning.
> 
> All wood burning appliances (as far as I know) have a chimney draft specification. I don't know how that could be consistently met without the use of a barometric damper. Some use a key damper to limit draft but those have issues too and are far from consistent.



I was thinking this but I wasn't sure because the probe thermometers say they are for double wall stovepipe. It is possible that when i am burning a lower fire my stack temps are actually up closer to where they need to be but I am not seeing it. I think I'll install one of the probe type thermometers and see where that gets me.

The chimney draft spec. according to the manual I have is -0.05 inches of water. That is the same spec. for my old oil boiler. With the damper set at that setting it stays closed when i first start a fire. After the fire starts going and the temp rises to about 300 on my gauge the damper starts becoming pretty active and you can hear the air moving through it and up the stovepipe. When the oil side kicks in the damper does it usual thing that it does on oil appliances. When it first fires it jumps and then it is open just a little the entire time the burner is running.


I wasn't sure about the placement of the damper. The guy that installed my boiler put it right behind the boiler and left about 2 feet between it and the chimney. This leaves me no place for the thermometer but after the damper. So, all of my temp reading are past the damper. I was considering moving the damper but I don't really know much about them other than I need one. The guy that installed my boiler knows more than me so I just assumed he was right. I wanted to move the damper and put it just before the stovepipe goes into the chimney but I'm not sure if this is the proper place for it and I don't want to send a bunch of cold air up my chimney and screw up the draft.


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## Carl Webber (Dec 2, 2014)

Whitepine2 said:


> Before the outside boiler fires were often,what I found is a dry extinguisher at the bottom of chimney
> would put out fire as quick as anything and not do any damage.THE DRAFT JUST PULLS THE POWDER UP PUTTING THE FIRE OUT.



I have a dry chemical extinguisher in the basement near the boiler. I'll have to remember this in case I have a chimney fire that the Chimfex won't take care of.


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## Carl Webber (Dec 2, 2014)

peakbagger said:


> I have a non gasification boiler and my neighbor had a non gasification boiler. He has multiple chimney fires despite cleaning his chimney monthly in the winter. He got to the point that he cracked his masonry liner and then burned up an insulated liner. I have cleaned my chimney twice in 25 years as it doesn't need it.
> 
> What is the difference? He burns wood that at best is 6 months old. He runs the boiler continuously allowing the damper to operate when there is no heat demand. He has a exterior masonry chimney. I have an interior one.  I added 550 gallons of unpressurized water storage 3 years ago and prior to that only ran the boiler when there was heat demand and watched the fuel so the damper rarely closed. The vast majority of gasification boilers have storage and most companies will not guarantee units that don't have it. My goal is to season my wood 2 years but the reality is that I have burnt wood that as cut in March and burned In December. I use more wood when the wood is not super dry but I have not seen an increase in creosote.
> 
> To me the biggest thing you can do is add storage. Even if you upgrade to a gasifier in the future, the tank will still be needed. That's what I plan to do. If you don't have storage, you have to accept significant temperature swings in the house and match your fuel load so that the boiler always stays below the temperature where the damper closes. This effectively limits you to only very cold weather.




How exactly do you burn? Do you burn only in really cold weather and keep a smaller fire so the damper stays open, or do you just have a fire when the heat is necessary to bring the boiler up to temp and burn hot when you do it? The other day it was cold here, about 20 during the day and 5 at night. Even then I couldn't keep a fast burning fire going without overheating the boiler. The house requires about 80k btu an hour and I also have a modine in the basement to dump heat if necessary. My boiler running wide open supposedly will put out 140k btu. If I build to big of a fire I get a bed of coals that is about 3 or 4 inches thick that give off a lot of heat and the boiler heats up really fast and takes a long time to cool down even with the over heat control running. I did find with the colder weather the damper stayed open more, but as the fire burned and I added more wood as it went down the bed of coals got bigger. I was a little nervous that If i got too big bed of coals I could overheat the boiler enough that it would get out of control. Right now If I have a small bed of coals and i throw some smaller wood on it the stack temps get up high enough and the fire burns hot and pretty fast, but if the boiler does hit 200 and the over heat kicks in it will only run for about 5 minutes to bring the boiler back down to 195. Because I'm new to this It worries me that I might get myself in a jam that I can't get out of and I might lose control of things. I've had wood stoves before but those are easy. They can get hotter and hotter and it doesn't matter, it just throws the heat into the room. With a boiler it collects the heat and stores it in the water and that makes it harder to work with. It also makes it more dangerous.


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## Deering (Dec 2, 2014)

Any thoughts on the various sprays and 'presto logs' out there that claim to have some sort of catalyst that helps to break down chimney creosote?  Are they effective or are they just more snake oil?


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## BrotherBart (Dec 2, 2014)

They work when used as instructed. Ya still need to brush the accumulation out of the chimney after using them. They just dry out wet glazed creosote. Not clean the pipe.


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## Deering (Dec 2, 2014)

Good to hear.  Cleaning out loose creosote sure beats the glazed stuff.  Thanks.


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## Carl Webber (Dec 2, 2014)

I had heard that they were bad for wood boilers that were constructed of plate steel because the chemicals are corrosive and can eat the metal. I had heard that they work to clean the chimney but that they harm the boiler in the process.


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## BrotherBart (Dec 2, 2014)

My big Sierra insert was made of 1/4" and 3/8" plate steel and 21 years of using the stuff didn't hurt it. Bought a case at the start of every season.


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## Carl Webber (Dec 2, 2014)

Good to know. I think I might give it a try and see what happens.


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## peakbagger (Dec 3, 2014)

I got the boiler for free and tried to run it for several years without storage. Its is a bottom grate design with air coming in under the grate so its doesn't hold coals. I tried all sorts of ways of running it without storage and ended up only using it during cold weather or when I the house was cold after I came home after being away for a few days. Unless I wanted to watch it continuously, I couldn't get it to run continuously without the air damper closing. The alternative is to have a big box of kindling and start it every several hours.


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## Carl Webber (Dec 3, 2014)

That is what I have been doing with mine. I found if I ran a fire that smoldered for awhile, I could let it go out and let the boiler cool to about 155 just before the oil kicked in, then I'd start a fire and run it hot because I had the 30 degrees to go and it would burn off the creosote. So, I started burning like that. I'd light a fire once every couple hours. If I built up the bed of coals too much without letting it burn down the boiler would get too hot. The only problem I found is that it means I need to constantly keep an eye on the boiler. I was considering rigging something up so a buzzer would go off about 5 degrees before the oil kicked in so I would know the boiler needed attention. This would also be very helpful during the night. Then I could just sleep till the buzzer went off and then get up to mess with the boiler. It would take the guess work out of how long the boiler will last before needing attention. On really cold nights it might only go 2 1/2 hours. On a warmer night it might go 4 hours.


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## Fred61 (Dec 3, 2014)

Wow! You're making my very happy to have storage. I could just see myself stumbling around in the middle of the night pissing in the boiler and lighting a fire in the toilet all winter long.


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## maple1 (Dec 3, 2014)

Carl Webber said:


> That is what I have been doing with mine. I found if I ran a fire that smoldered for awhile, I could let it go out and let the boiler cool to about 155 just before the oil kicked in, then I'd start a fire and run it hot because I had the 30 degrees to go and it would burn off the creosote. So, I started burning like that. I'd light a fire once every couple hours. If I built up the bed of coals too much without letting it burn down the boiler would get too hot. The only problem I found is that it means I need to constantly keep an eye on the boiler. I was considering rigging something up so a buzzer would go off about 5 degrees before the oil kicked in so I would know the boiler needed attention. This would also be very helpful during the night. Then I could just sleep till the buzzer went off and then get up to mess with the boiler. It would take the guess work out of how long the boiler will last before needing attention. On really cold nights it might only go 2 1/2 hours. On a warmer night it might go 4 hours.


 
You could try shutting the oil burner off all together, and just make a fire when the house starts feeling cold.

That's what I did with my old one. Just wired in a simple wall switch between the burner & aquastat that I kept turned off when I was around & able to make fires & didn't need backup heat.

(i.e. let the boiler go colder than 155).

Or change your stat settings so it doesn't kick in until it gets down lower - like 130-140.

You could also heat the house warmer while burning & use the house itself as heat storage. For example with a well insulated basement you could heat that up to 80 (or whatever), then that heat might rise up over night & help you make it through the night.

With my old one I had a hard enough time just dealing with trying to load late & refill as soon as I woke up in the morning - can't imagine getting up in the middle of the night multiple times to tend it. I think I would have to let the oil burn some rather than do that, would have sent me off the deep end. Storage does indeed change everything - now my fire is about out when I go to bed and I don't relight it until the next afternoon sometime.


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## Carl Webber (Dec 4, 2014)

I made some changes to my system and it has changed how I burn. I took apart the stovepipe and cleaned it. It had a good layer of creosote on it from me learning how to burn properly the first couple days I burned. Since I started out bad it has continued to accumulate pretty good. So, after cleaning I took a camera and held it in the chimney facing up and took a picture and the chimney doesn't look too bad. There is definitely some creosote buildup but not too much. The other thing that made me happy was that it was the dry crusty stuff and no the glassy sticky stuff. The way things are looking I'm pretty sure I could burn for probably 2 months without having to worry about the buildup. After that amount of time I don't think the chimney would be anywhere near plugged but it would have a pretty thick layer and it would mean the risk of a much worse chimney fire would be higher.

When I put the stovepipe back together I moved the barometric damper so it was just before the elbow into the chimney. This put it about two feet from the boiler. I also went and bought a probe type thermometer and installed it before the damper. It said to install it a little more than 18 inches up the stovepipe, I went to 19 inches. After setting the boiler up like this I have discovered that I have been burning too hot. With the baffle in the top of the boiler at a 45 I can easily overfire the boiler in about 10 minutes even with the draft door almost closed. It doesn't take much and the temp is up to 900. If I put the baffle straight up (the way it is meant to run), the fire burns much longer and it burns between 400 and 500. Its not in the middle of the optimal burn zone but it's in. Lesson here is the right thermometer and the location of the thermometer make all the difference in the world.

Burning like this, I see more glassy creosote buildup in the boiler but the stovepipe seems to be pretty clean. I've been watching it through the back of the boiler and through the damper and I can see a little creosote buildup but nothing compared to the inside of the boiler. What I have done to combat this is about twice a day I'll move the baffle in the top of the firebox and i'll throw in a stick or two of wood and have a small fire that burns really hot, about 900, right at the top of the optimal burn zone but not yet overfiring. I'll let it burn like this for 10 or 20 minutes watching it and adjusting as necessary to make sure the temp doesn't climb too high. This seems to burn off a lot of the buildup in the boiler. Then I can take a wire brush to the doors and openings in the boiler and everything just flakes right off and I clean it up pretty nice in about 5 minutes.

Running like this has made the boiler much more manageable and burns much less wood. Last night I went to bed at 11:30pm and I stoked the fire and filled the firebox up to the bottom of the door, about 5 or 6 sticks of wood. When I got up this morning at 7:30am the boiler was still at 180 and there was enough coals for me to be able to throw a couple smaller pieces of wood on and start a new fire without having to use kindling. That works out to roughly an 8 hour burn on one load of wood. Much, much better than I was getting before.

I don't know if anyone else has experienced this, but I did notice something about my boiler that I'm not sure If its a good or bad thing or what to do about it. I noticed that running the boiler like I am the wood doesn't burn as fast and that means that it sits in the firebox and tuns to coals. Once I get a good bed of coals going everything burns nice and slow and clean. The problem I am seeing is with heat. I had about 3 or 4 inches of coals in the firebox and 3 sticks of wood on top. They had worked their way down as the wood under them burned. These three sticks of wood were charred and ready to burn but because of the way the draft was controlling the boiler they hadn't burned yet. I went to check on the fire and as soon as I opened the door to see what the wood and the fire looked like they lit and because of the way the boiler is designed the smoke and flames shot through the bed of coals and up through the heat exchangers. It caused a pretty loud roar and the stack temp almost immediately went to overfire, somewhere near 1000. Of course as soon as this happened I shut the door to starve the fire of the extra oxygen it was pulling through the door. After shutting the door and closing everything up tight it took about 15 or 20 minutes for the stack temps to come down into the normal operating range below 800. What makes me nervous about all this is that it reminds me of what firefighter would call backdraft. Everything is ready to burn but not enough oxygen is preventing it from burning. As soon as it gets the oxygen it burns super hot and fast and almost instantly. It made me nervous that some day I would go to check on the fire and just by opening the door I would cause a chimney fire. For now what I've found is that after the fire burns down to only a few coals and really needs to have wood added the stack temps drop down to about 250 or 300. Just below the optimal burn range. When I check the fire now I check the temp of the boiler and the temp of the stack. If the stack temps are still in the optimal burn range I leave everything alone. I won't even open the door. If the stack temps are low then I open the door to check the fire. If anyone has any experience with this or any suggestion It would definitely be helpful.


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## brenndatomu (Dec 6, 2014)

Sounds like you should give 'er some air for a few minutes before opening the door. Prop open the damper or whatever controls the air on that machine...


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## b33p3r (Dec 6, 2014)

I am not 2 years ahead with my wood storage yet but I haven't had any problems with creosote in my chimney. In fact my wood is about 1 year dry at best. I do however clean the chimney every 3 months. Been burning since September so am due to clean now. 
    I have also been told by an old timer that if you throw an aluminum can into your stove the chemicals it produces when it burns helps clean the creosote. I don't know if it works but I do so enjoy that beer as I load the stove for the night   I think he said it had to be a beer can?


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## Carl Webber (Dec 7, 2014)

Do you have a traditional boiler or a gassification boiler? Do you have storage?


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## Carl Webber (Dec 22, 2014)

I just cleaned my chimney today after 1 month of burning just to see what it looked like. To my amazement my chimney was absolutely clean except for a very thin layer of glassy creosote that was fresh. The fresh creosote was because apparently one of the sticks of wood that was put in the boiler last night was not very dry. It made a real mess of the inside of the boiler and put a layer of creosote up the chimney. I did notice one problem that I kind of expected. The chimney is clean but the stovepipe that connects the chimney and the boiler had a pretty good layer of creosote. Because I've been using Kwik Shot creosote sticks the stuff in the stove pipe came right off and cleaned up nicely. There was quite a bit. I would say at least a quarter inch all the way around maybe a little more. Does anyone have any solutions to this? Is it possible to insulate the stovepipe somehow so it doesn't collect so much creosote? What about double wall insulated stovepipe? Has anyone tried something like this before? If so, how did you connect the insulated pipe to the uninsulated thimble in the chimney without switching back to the regular single wall stuff?


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## bpirger (Dec 22, 2014)

I was driving home late (about 2AM) a couple of weeks ago from work, out in the rural area.  I came across one of those giant clouds of wood smoke settling in the small valley....could see it 0.5mile ahead.  As I got closer I noticed someone was out burning a fire (at 2AM) in the yard, really close to the house.  Then I noticed there were three separate fires!  It was clear the guy had a chimney fire occurring/just over/or just coming and stuff had belched out his pipe and started the fire.  I turned around and went back, knocked on the door, and was somewhat concerned I might get shot.  No answer....so I tried to stomp out the fire a bit....then started knocking on windows.  Loud "hellos" to help thwart the bullets from flying.  He came out and was stunned.  We put out the fires....which had started in the leaves right next to the house and in the bushes.  Looked like the leaves hadn't been raked in years.  His wood pile, nothing split, stacked along the side of the house, was actually on fire.  Imagine a couple of camp fires....that is what was going on...less than 3' from the house wall.  Looked like the shingles on the walls of the house were old particle board/asbestos type...and one of them was quite severely burned.   We put out the fires, he brought water out one gallon at a time, and I mentioned the idea of cleaning the chimney!   No cap either.  Without a doubt, I saved his house that night....who knows about people inside  Next day I see he had raked the leaves up.....a good start.  Thought about calling 911 and was just about to when he emerged.  As I drove away I still wondered if I should call....maybe there'd be some education involved.  It was apparent he didn't have too many resources to do things right.   It's scarey how so many people do things.....and clear why so many fires happen.


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## Pat53 (Dec 22, 2014)

well done, you may have saved more than just his house.


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## TimfromPittsburgh (Dec 25, 2014)

I've been heating with wood for 20+ years and am still learning the art of properly firing a wood burner. Our is a one story house with the boiler in the basement. The boiler connects into a massive brick chimney in the center of the house with three tile lined flues. We have never had a chimney fire. We burn both pine and hardwoods that have been seasoned at leasst one year, but generally two years. I do have the chimney cleaned every year prior to heating season. Each cleaning produces about five pounds of fluffy creosote that is knocked of the flue tile by the cleaning brush. After cleaning there remains a coating of hard, somewhat shiny black tar like coating on the flue tiles.

That we have never experienced a chimney fire is partially good luck, because I know now that there were times when I was seriously overfiring the boiler and undoubtedly dumping dangerously hot exhaust gasses into the flue. About 10 years ago I started using a flue gas thermometer to monitor temperature in the flue and have come to realize that this is the most valuable indicator I have for monitoring and controlling the wood burner. There has always been a barometric draft damper in the flue, but I found this was not sufficient to control the firing rate and flue gas temperature, so I have added a manual draft damper which I tweak as needed to keep the maximum flue gas temperature below 800 degrees.

A couple years ago I added heat storage, with which I was able to reduce the percentage of time the boiler was idling nearly to zero, but to my suprise I am still getting about the same amount of creosote each year when the chimney is cleaned. What I did find is much less creosote accumulation in the boiler's fire tubes.

Based on my experience I believe the amount of creosote deposited in the chimney is mostly related to the amount of wood burned, and if I clean the chimney regularly and control flue gas temperature I will not experience a chimney fire.


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## Carl Webber (Dec 25, 2014)

TimfromPittsburgh said:


> I've been heating with wood for 20+ years and am still learning the art of properly firing a wood burner. Our is a one story house with the boiler in the basement. The boiler connects into a massive brick chimney in the center of the house with three tile lined flues. We have never had a chimney fire. We burn both pine and hardwoods that have been seasoned at leasst one year, but generally two years. I do have the chimney cleaned every year prior to heating season. Each cleaning produces about five pounds of fluffy creosote that is knocked of the flue tile by the cleaning brush. After cleaning there remains a coating of hard, somewhat shiny black tar like coating on the flue tiles.
> 
> That we have never experienced a chimney fire is partially good luck, because I know now that there were times when I was seriously overfiring the boiler and undoubtedly dumping dangerously hot exhaust gasses into the flue. About 10 years ago I started using a flue gas thermometer to monitor temperature in the flue and have come to realize that this is the most valuable indicator I have for monitoring and controlling the wood burner. There has always been a barometric draft damper in the flue, but I found this was not sufficient to control the firing rate and flue gas temperature, so I have added a manual draft damper which I tweak as needed to keep the maximum flue gas temperature below 800 degrees.
> 
> ...


Have you noticed more buildup in the stovepipe connecting the boiler to the chimney than the chimney itself? I've only been running my setup for about 6 weeks and i've noticed creosote buildup in the boiler itself and in the connecting stovepipe but the chimney seems to be clean other than the fine film of glassy black creosote like you mentioned.


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## bholler (Dec 26, 2014)

TimfromPittsburgh said:


> Each cleaning produces about five pounds of fluffy creosote that is knocked of the flue tile by the cleaning brush. After cleaning there remains a coating of hard, somewhat shiny black tar like coating on the flue tiles.


I cant be sure but usually stuff described as "fluffy creosote"  Is burnt creosote and is evidence of a chimney fire.  When was the last time you had your flue scanned and professionally inspected?  And if you are getting 5 pounds of it every year with glaze left in the chimney it sounds like you need to clean more often and change your burning practices.


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## TimfromPittsburgh (Dec 26, 2014)

Carl Webber said:


> Have you noticed more buildup in the stovepipe connecting the boiler to the chimney than the chimney itself? I've only been running my setup for about 6 weeks and i've noticed creosote buildup in the boiler itself and in the connecting stovepipe but the chimney seems to be clean other than the fine film of glassy black creosote like you mentioned.


I can't comment on the thickness of accumulated creosote on the chimney wall as I have not looked down the chimney just before the chimney sweep does his thing with the brushes. I do remove the connecting stove pipe and clean it every year and routinely find about a 1/2" layer of fluffy creosote and ash clinging to the inner surface of the pipe (my stove pipe is 6" diameter). Next time I will look down the chimney before it is cleaned. What I can say for certain is that the tar & creosote buildup on the inside of the boiler (in the firebox) is minimal and has vastly decreased since I added heat storage.


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## TimfromPittsburgh (Dec 26, 2014)

bholler said:


> I cant be sure but usually stuff described as "fluffy creosote"  Is burnt creosote and is evidence of a chimney fire.  When was the last time you had your flue scanned and professionally inspected?  And if you are getting 5 pounds of it every year with glaze left in the chimney it sounds like you need to clean more often and change your burning practices.


I really don't know what the significance of fluffy creosote is. Maybe some others can comment on that. I have not had my flue scanned, however the gentleman who cleans my chimney is a professional chimney sweep. He does a visual inspection of the chimney as part of his service and tells me when he sees something that needs attention. I estimate that I burn about five cords of wood per year. Should I be conceerned that this produces five pounds of creosote?


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## bholler (Dec 26, 2014)

TimfromPittsburgh said:


> I estimate that I burn about five cords of wood per year. Should I be conceerned that this produces five pounds of creosote?



Yes i burn about 6 cords and make about a quarter gallon on a 40 year old stove


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## Carl Webber (Dec 26, 2014)

I think I need to get a moisture meter and check my wood for moisture content. I know it has been down and cut and split since before last winter so it is reasonably dry. The chimney doesn't seem bad and the connecting stovepipe has some buildup but the inside of the boiler seems to have a lot of creosote buildup. For my boiler it doesn't seem that bad to me because I have heard stories of people with my boiler that get large amounts of creosote running out the doors like thick tar and making a complete mess. I don't have that problem but i do notice once in awhile the door sticks a little and i see a spot where some creosote ran down the door and stuck the door to the frame. I also notice that sometimes there is creosote running down the door frame after a burn. Sometimes I see it even if I had a hot burn. It is soft a gooey and I try to scrape as much of it off with a putty knife as I can. Sometimes I can even see a couple of runs on the wall of the firebox inside the boiler. I try to use the Kwik-Shot sticks twice a week as it recommends to dry out the creosote. I do notice after using those a layer of creosote drys and peels off the next I have a really hot burn.


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## maple1 (Dec 27, 2014)

bholler said:


> I cant be sure but usually stuff described as "fluffy creosote"  Is burnt creosote and is evidence of a chimney fire.  When was the last time you had your flue scanned and professionally inspected?  And if you are getting 5 pounds of it every year with glaze left in the chimney it sounds like you need to clean more often and change your burning practices.


Fluffy creosote doesn't mean chimney fire. A chimney fire leaves nothing behind if it burns out on its own accord.


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## bholler (Dec 27, 2014)

maple1 said:


> Fluffy creosote doesn't mean chimney fire. A chimney fire leaves nothing behind if it burns out on its own accord.


No not necessarily many times it leaves behind a fluffy expanded creosote.  There are times that it burns clean but that is actually pretty rare and only comes from very intense fires which are much less common that the slower ones that leave behind the expanded fluffy stuff.  Now without seeing the dirt that the poster was talking about i cant say but fluffy is a common description of it


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## Carl Webber (Dec 27, 2014)

bholler said:


> No not necessarily many times it leaves behind a fluffy expanded creosote.  There are times that it burns clean but that is actually pretty rare and only comes from very intense fires which are much less common that the slower ones that leave behind the expanded fluffy stuff.  Now without seeing the dirt that the poster was talking about i cant say but fluffy is a common description of it



So, what should the creosote look like in a chimney? I was under the impression that if you had the fluffy ash looking stuff that it meant you burned cleaner and there was nothing in your chimney that was at risk of catching on fire? What I'm hearing from everyone is that if you have fluffy looking stuff it means that the actual creosote has burned off and what you are actually scraping out of the chimney is the ash that is left. Is this really a problem as long as the creosote doesn't actually catch fire and get out of control?


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## maple1 (Dec 27, 2014)

Fluffy stuff can catch fire too.


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## TimfromPittsburgh (Dec 27, 2014)

bholler said:


> Yes i burn about 6 cords and make about a quarter gallon on a 40 year old stove


Thats interesting. I have no clue as to why my wood burner should be making so much more creosote on less wood burned. I do have a barometric draft damper in the flue and it is usually partially open when I am burning. I'll bring that up with my chimney sweep next summer and get his take on the amount of creosote my wood burner is producing.


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## TimfromPittsburgh (Dec 27, 2014)

Carl Webber said:


> I think I need to get a moisture meter and check my wood for moisture content. I know it has been down and cut and split since before last winter so it is reasonably dry. The chimney doesn't seem bad and the connecting stovepipe has some buildup but the inside of the boiler seems to have a lot of creosote buildup. For my boiler it doesn't seem that bad to me because I have heard stories of people with my boiler that get large amounts of creosote running out the doors like thick tar and making a complete mess. I don't have that problem but i do notice once in awhile the door sticks a little and i see a spot where some creosote ran down the door and stuck the door to the frame. I also notice that sometimes there is creosote running down the door frame after a burn. Sometimes I see it even if I had a hot burn. It is soft a gooey and I try to scrape as much of it off with a putty knife as I can. Sometimes I can even see a couple of runs on the wall of the firebox inside the boiler. I try to use the Kwik-Shot sticks twice a week as it recommends to dry out the creosote. I do notice after using those a layer of creosote drys and peels off the next I have a really hot burn.


I have experienced the runny tar-like goo running down and out the primary air draft door beneath the grate. It became a problem when the boiler was idleing a lot. Now that I have heat storage, the boiler rarely idles and I have not had to deal with the goo. I think this tarry liquid comes from liquid and vapors emitted from wood baking in the firebox that condense on walls of the boiler when the boiler is idleing and it is not hot enough to burn them. If you load the firebox very full, the wood near the top of the firebox isn't very hot and may be emitting vapors that create the tarry liquid.

I've thought about getting a moisture level meter as well. Here in Western Pennsylvania we have a lot of humid days that makes air drying wood challenging.


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## Carl Webber (Dec 31, 2014)

TimfromPittsburgh said:


> I have experienced the runny tar-like goo running down and out the primary air draft door beneath the grate. It became a problem when the boiler was idleing a lot. Now that I have heat storage, the boiler rarely idles and I have not had to deal with the goo. I think this tarry liquid comes from liquid and vapors emitted from wood baking in the firebox that condense on walls of the boiler when the boiler is idleing and it is not hot enough to burn them. If you load the firebox very full, the wood near the top of the firebox isn't very hot and may be emitting vapors that create the tarry liquid.
> 
> I've thought about getting a moisture level meter as well. Here in Western Pennsylvania we have a lot of humid days that makes air drying wood challenging.



In the last week or so my girlfriend has loaded the boiler at bed time when I was at work and forgot to open the small draft adjustment on the loading door. This small draft is supposed to allow air in to mix with the flue gasses and burn them when they mix while getting sucked back through the bed of coals. I have noticed that makes a huge difference. If this draft is open I don't get too much buildup. If this little draft is closed the amount of buildup is unbelievable. It runs down the inside of the door and is dripping off the top and walls of the firebox. it doesn't appear like it does much as far as gunking up the chimney but it sure makes a mess of the boiler. I haven't decided what to do about this yet. The reason that little draft gets closed is because when you open the cleanout door to poke the fire and move around the coals it put a lot of smoke out that little draft. To stop the smoke we shut the draft and then open it up again when we close the cleanout door. If it happens many more times I may just tell her to leave the draft open and let the smoke in the house and just be quick when opening the cleanout door. Its a real mess to clean up after the boiler gets full of that nasty black gunk.


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## TimfromPittsburgh (Dec 31, 2014)

Carl Webber said:


> This small draft is supposed to allow air in to mix with the flue gasses and burn them when they mix while getting sucked back through the bed of coals. I have noticed that makes a huge difference. If this draft is open I don't get too much buildup. If this little draft is closed the amount of buildup is unbelievable. It runs down the inside of the door and is dripping off the top and walls of the firebox.


Interesting. Currently the draft on my loading door is open about the width of two fingers, but it hasn't always been that way. This past summer I did some major maintenance on the boiler which included freeing up that draft which had been stuck closed for some time.

The only time I ever had a boiler discharge through the pressure relief valve was when the black tarry stuff pooled up on the primary draft door preventing it from closing completely. 

I was unfamiliar with the OT-50 so I looked it up in the Tarm archieves. It looks like the OT-50 might be the predicessor to the Tarm 502. How hong has your boiler been in service?


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## Carl Webber (Jan 10, 2015)

I had my boiler installed about 2 months ago. When i got the boiler back in September it had some issues that needed to be fixed but nothing major. It appeared to me like the previous owner only used the oil side. When i got the boiler it had last been serviced about a year before so it hadn't been sitting for too long. One of the flanges on the back had to be replaced because it had a pinhole in the weld and was rusted pretty bad because someone had neglected to fix the original leak. at least one hinge pin on all three doors was broke and had to be drilled or pounded out and replaced. The domestic hot water coil was blown but i wasn't planning on using it anyway so I removed the coil and put in plugs. The gasket for the cover of the hot water coil was also dry rotted and leaking. After fixing all that stuff the boiler looked almost new. Because no wood had ever been burned in it the inside was immaculate. It seems like a lot of work on an old dinosaur but it was what I wanted and at the right price. I only paid $650 for it. There is a guy near me that refurbishes them and sells them on ebay  and he gets about $2500 for one. I've also seen plenty of other ones in worse shape than mine that people have wanted $2000-$3000 for them. As I was trying to upgrade from oil to a wood oil combo and do it as cheaply as possible i was willing to put in a little elbow grease and get the cheaper one. For now I have also skipped the thermal storage. after a year or two and I've recouped the money I invested I'm going to install some storage. After that I'm going to try to upgrade to a gassification boiler. I haven't decided how i'm going to do things yet. I may go cheap and get an excel 2200. This would allow me to upgrade to a gassification model but keep the oil backup.


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## Carl Webber (Jan 10, 2015)

has anyone had an issue with their chimney cap falling apart. I just found the top of my chimney cap in the middle of my yard. There is a little creosote built up on it and it appears almost like the creosote mixed with some moisture and ate the spot welds that held the cap on. Has anyone ever seen this before? I think I'm going to just drill some holes and bolt the top to the screen instead of buying a new cap. It just amazes me that it fell apart. I have never seen this before.


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## maple1 (Jan 10, 2015)

I found my cap in my yard once, but it blew off. I straightened it out, climbed on my roof, & screwed it back on. I must not have screwed it on tight enough.

Yours has a screen? I've never had one on my caps, but from reading of others issues they can sometimes be more trouble than they're worth, for building creosote & blocking things up. I did have a birds nest in my chimney once - and there was an episode once when I was away from home where two bats mysteriously suddenly appeared inside the house & caused all sorts of panic. Didn't see it but never heard the end of it....


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## Carl Webber (Jan 10, 2015)

It isn't exactly a screen, but that is the best way i could think to explain it. It the expanded metal section of the chimney cap. The actual top of the chimney cap separated from the expanded metal section. They were tack welded together and the welds are completely gone now.


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## longboarder2 (Jan 11, 2015)

This could be a lot of typing.

Carl, four years ago, I had a chimney fire that could've claimed my whole second floor and the three kids that were sleeping there. I needed to get educated quick! Most of the wisdom came from this forum. I live in nj and have been successfully burning a harman sf160 since. Chimney sweep brushed my 28' tall pipe last week---everything that came out would've fit in a coffee can. If You want some tips on running that smoke dragon cleanly, call me any time @ 609-868-1878. Would be glad to help you out as others have helped me.


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## maple1 (Jan 11, 2015)

You should post your tips - might help more people.


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## Carl Webber (Jan 12, 2015)

as far as I can tell my chimney is pretty clean. I cleaned it a week or two ago and got almost nothing. I have found that the majority of the creosote is in the boiler and in the stovepipe that connects the boiler to the chimney. I'll have to check it again sometime in February or march just to see what it looks like but I think I will probably only have to clean my chimney once a year. The connecting stovepipe and the boiler will need some attention a little more frequently. I can look through the boiler and see right into the stovepipe and I can also look into the barometric damper. By doing this I can keep an eye on how things look and just clean it as i feel is necessary.


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## JrCRXHF (Jan 14, 2015)

I agree with what most are saying. I have a stainless liner inside the normal liner with insulation poured all around it. I also have fiber blanket on the stove pipe on its way to the chimney in the wall in my boiler room to keep as much heat as possible in the stove pipe. 

The other thing i do is check my wood and burn what shows to be the lowest % moisture. The thing that i think helps me a lot too is that i don't have room in the house for hot water storage so i turn down the heat to 50F when i go to work and when i get home i fire up the wood boiler and it runs wide open (about 500-550F) with a IR for about 1.5-2 hours to bring the house back up to temp after that the amount of wood i put in the boiler is much less. I have a harmon SF-260 that i bought used and i am making it work.  I also don't use the boiler much unless the outside temp is below 25F or so. If it is warmer then that i burn NG.


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## Carl Webber (Jan 21, 2015)

JrCRXHF said:


> I agree with what most are saying. I have a stainless liner inside the normal liner with insulation poured all around it. I also have fiber blanket on the stove pipe on its way to the chimney in the wall in my boiler room to keep as much heat as possible in the stove pipe.
> 
> The other thing i do is check my wood and burn what shows to be the lowest % moisture. The thing that i think helps me a lot too is that i don't have room in the house for hot water storage so i turn down the heat to 50F when i go to work and when i get home i fire up the wood boiler and it runs wide open (about 500-550F) with a IR for about 1.5-2 hours to bring the house back up to temp after that the amount of wood i put in the boiler is much less. I have a harmon SF-260 that i bought used and i am making it work.  I also don't use the boiler much unless the outside temp is below 25F or so. If it is warmer then that i burn NG.



I have also found that if it gets to be between 25 and 30 outside I have a hard time running the boiler without making the house get up to 80. On the warmer days I let the wood burn out in the morning and i turn on the oil and let that keep the boiler warm all day. Then I start a fire again at night once it starts to cool off. Usually I watch the temp outside and I wait to see what the house does. When I see the heat kicking on in the house and the outside temp is getting lower I will turn off the oil and let the boiler temp drop down to the point that it shuts off all the circulators usually about 160. Then I start a fire. Usually this first fire will get good and hot and build up a good bed of coals and will burn hot for about 2 hours. By that time the boiler will be up to temp and the house will also be up to temp.

Where did you get the fiber blanket to insulate the connecting stovepipe? I have thought about doing this but don't know where to get the right kind of insulation. Just to be safe I wanted to insulate the connecting stovepipe but I'm not sure that I need to. My boiler is only about 50% efficient on wood so a lot of heat goes up the chimney. I've seen times where the stack temp before my barometric damper were 1100 and and after the damper they were 800. I try not to get things this hot but it does happen once in a awhile. On a normal day my stack temps are about 450 before the barometric damper and between 250 and 300 after. What I was hoping was that with a little insulation I might be able to get the temps before and after the barometric damper to be a little closer. If the connecting pipe is seeing 450, it would be nice if the chimney could consistently see 300 to 350.


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## JrCRXHF (Jan 29, 2015)

http://www.amazon.com/Ceramic-Insulation-Blanket-QuadraFire-Stoves/dp/B00CJNE3QI


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## Carl Webber (Feb 3, 2015)

JrCRXHF said:


> http://www.amazon.com/Ceramic-Insulation-Blanket-QuadraFire-Stoves/dp/B00CJNE3QI


Thanks, I think I'll invest in some of this and see what it does. It can't possibly make things worse.


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