Chimney Creosote

SS MAYFLOAT

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May 17, 2001
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I came close to having a chimney fire over the weekend. Saturday morning I kept having problems getting a draft going. I would go outside and would see smoke coming out, but still getting smoke coming out of the woodburner and its stove pipe. So I dampend all the intake air and let the fire die out.<br /><br />Sunday I took off the stove pipe and run a wire brush through it. Got soot out, but it wasn't plugged. Started another fire and still the same thing.<br /><br />Started up the bucket truck and used it to look down the chimney. Oh Boy, after shinning the flash light down in it I could see that it was plugged. I couldn't believe the buildup of creosote. So I took a length of rope and my triball trailer hitch receiver (about 12 pounds) and dropped it down the chimney. It knocked out the plug with one drop of it. I did it several more times letting it scrap against the side of the chimney knocking off more gunk.<br /><br />Now I have a good draft and back in business.<br /><br />I did burn one of those chimney sweeping logs yesteday to see if it will do what they say it does. <br /><br />Is there anything else that can be burnt to help reduce the buildup on the walls of the chimney?<br /><br />Thanks
 

SS MAYFLOAT

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Re: Chimney Creosote

I mostly have been burning silver maple, walnut, some elm, cataupa, and locust. I don't burn any kind of evergreen because I know they have a very high content of creosote.
 

bubbakat

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Oct 29, 2002
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Re: Chimney Creosote

SS I have been burning wood for years and I have found the only way to keep that stuff down is to manually bump it out about three time in the winter. Just as you did.<br /> I dried my would for two summers and burn on the second winter, Keep in mind now this wood is stored in the dry so moisture wasn't the issue and it still builds up.<br /> If you have an elbow in in the pipes it seems to build up more frequently.<br />It is going to have its ups and downs but in my humble opinion its still worth it.<br />(edited) you will get a lot of creosote from locust
 

OBJ

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Dec 27, 2002
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Re: Chimney Creosote

I burned wood for about 5 years till I got tired of cuttin' wood of every spare minute I had.<br /><br />I had a SS liner in the old brick chimney and I would as least once a day just let the fire go and burn the crap outta it. Never had any soot or creosote problems and I burned a variety of wood. Don't know if this would work for chimneys with clay liners though.
 

mellowyellow

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Jun 8, 2002
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Re: Chimney Creosote

wow SS! sure glad it didn't happen while you all<br />were sound asleep. a real good lesson for all of<br />you out there IMO.<br />the cleaning logs work good BTW.
 

Ross J

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Nov 30, 2001
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Re: Chimney Creosote

When I was in the fire brigade the chimmeny fire problem was at it's highest, with so many homes changing to 8" metal chimneys from brick chimneys of 12" x 24" flow. People just didn't sweep their stacks every year and were surprised how quickly the creosote built up.<br />With the metal chimney any moisture released from the logs burning is attracted to the cooler surface of the chimney and through condensation deposits build up creating blockage. I couldn't believe it when I stayed at a friends farm and the chimney was almost totally blocked. We had trouble even lighting the fire. It just would fail to draw. Up to the roof, a quick clean with a hunk of metal on a rope and the problem was fixed. Was he ever grateful!<br />Blasted house could have burnt down, remember creasote is a flamable product!<br />Sweep your chimney each season..<br />Ross<br /><br />PS over here if you fail to sweep the insurance refuses to pay out!
 

neumanns

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Mar 1, 2003
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1,926
Re: Chimney Creosote

A chimney fire is truly an awsome thing and should be avoided at all costs. I believe the best approach is regular cleaning/inspection. The other products proabably help but should not be a replacment for a good old fashioned cleaning IMO. Creosote is not flamable...it is HIGHLY FLAMABLE!!
 

steam_mill

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Jan 16, 2002
Messages
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Re: Chimney Creosote

I've not had a chimney fire but have had some issues with creosote. What I have found out is when dealing with woodstoves, the fire should be a hot fire always. This reduces creosote.<br /><br />So, if you need little heat, build a small fire with the dampers open so the fire roars. This reduces creosote.<br /><br />With metal chimneys, they are generally on the cool side which causes creosote. A hot fire compensates for this.<br /><br />Tx.<br /><br />Joe
 

JasonJ

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Aug 20, 2001
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Re: Chimney Creosote

My chimney is professionaly cleaned every fall. Every day, I run a super hot fire to burn anything off. My stove has one of those temp gauges that goes to 900 degrees, and has ranges that show the creosote building range, the best range, and the too hot range. 0-250 dgrees builds creosote, 250-475 degrees is the best operating range, and 475-900 is too hot. I'll run it up to about 600 degrees for about ten minutes, then throttle it back to about 300 degrees. I have had no problems using this technique, but this is my first winter in this house. We'll see what the chimney guy says next fall about how clean the chimney is. My stove is a big Fisher, its a great stove.
 

Boomyal

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Re: Chimney Creosote

JasonJ, are those temperatures measured on your vent pipe above the firebox or on the top of the fire box? <br /><br />I have a 16 y/o Vermont Castings catalytic wood stove. We burn about 4 cords of hardwood a year. I run the top of firebox temp between 550 and 650 deg. I used to run it at 700 to 750 but after 13 years I had to replace some warped cast iron pieces inside the stove so I now run it a bit cooler.<br /><br />I run an 8" internal (two story) metal chiminey, with two bends in it, and have only had to clean it two times in 16 years. The first cleaning produced about 1/2 of a one lb coffee can of residue. The second cleaning was after the catalytic converter had collapsed and I got about one 3 lb coffee can of residue. I've never had that glazed build up of hard creosote.<br /><br />If you have the option be sure to get a stove with a catalytic converter. Also, as has been said above, make sure that you start the fire fast and keep the temperature up and don't ever 'bank' the fire to keep it burning all nite. <br /><br />I had a neighbor who used to throw his Christmas tree in his fireplace every year to 'clean his chiminey out. He had a two story, external masonary chiminey. You could see the blue flames belching out the top of that chiminey when the creosote caught fire. It sounded like a jet engine. It was frightful. He finally saw the light and quit doing it because that was precisely what could cause a catastrophic house fire.
 

DC698

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Sep 6, 2003
Messages
138
Re: Chimney Creosote

SS, I've seen too many blocked woodstove flues with cresote build-up in them (14 year certified chimney sweep). I never recommend throwing anything heavy down the flues to unblock the chimney such as chains, cast iron balls etc.. as this can do more harm than good. Doing so can damage the terracotta clay liner especially if there is any type of offset in the flue. The best way to remove the large chunks of creosote is with the chimney rods and a spike tool, finished with a good cleaning with the steel bristled brushes. You cannot remove 3rd degree creasote without a mechanical or chemical process. I use the mechanical process as I personally dont like to use the chemical process (Its usually a 2-3 step process and costs the customer more). 3rd degree creosote is a very shiny non-removable glazing located on the flue walls. This is VERY VERY flammable. These "Chimney Sweeping Logs" (According to studies done by the Chimney Saftey Institute of America) do "loosen" up portions of the creosote from the flue walls but you still need to have the particles cleaned up at the breech area (Where the stove pipe meets the flue) and the flue cleaned and inspected annually. As someone else posted above... the worst habit to get into, is "Banking" the stove. Most of the homes that I do, that have woodstoves installed and have creosote problems, bank the stove at night. This creates too much smoke after the wood is burnt, and the smoke is drafting into a colder flue where the flue gas temperature is very low in essence creating a chemical reaction -- creosote. Burn only hard wood and burn the fire hot! Do not overfire the stove though.. you can damage/warp internal parts and wear them out quickly. Have your chimney checked annually by a certified chimney sweep. Go online to www.csia.org and find a certified sweep near you. I am not sure what kind of fuel you burn for your home heat (In New England its more Oil and Gas furnaces) but that also vents into a chimney and should be inspected, and if neccessary, cleaned YEARLY.(Yes, even Gas flues! CO poisoning is much too common!) If you have any questions, let me know.
 

SS MAYFLOAT

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Re: Chimney Creosote

Thanks, I took the advice and called in a professional to inspect and clean the chimney.<br /><br />Should I have the flue all the way open? When I do, flames shoot up the stack. Usually I run the flue about half closed, and the woodburner air damped just enough to make a good flame. <br /><br />Now with the creosote build up, I really don't want to run a real hot fire until its cleaned.<br /><br />Thanks again... :)
 

DC698

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Sep 6, 2003
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Re: Chimney Creosote

SS, If it was me, I wouldnt run the stove until it is cleaned by a professional sweep. Especially when you said it was almost blocked with creosote. I wouldnt take the chance. Make sure the company that you contract is a member of your state chimney guild (As an example, we are Mass. Chimney guild members) and that the guy that comes out is CSIA certified (He should have a badge with him w/ cert. #) Then at least you know you are getting a competent sweep who's learned the proper fire/building codes. He should be able to instruct you on the proper use of the type of stove you are burning. And again, make sure he inspects your heating flue and takes a draft reading with a Bachrach meter. Sounds like you are burning an older stove with no catylitic converter if you see flames coming up through the smoke pipe. -Derek
 

SS MAYFLOAT

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Re: Chimney Creosote

My Chimney tile is 8x12. Right now there is not any blockage. Just the sides have a coating them. I did take chimney wire brush and run it down about 8' from the top. It did knock down quiet a bit. I'm going to let it die out tonight. Hate to because it is going to be in the single digets. Brrrr..... :eek:
 

steam_mill

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Re: Chimney Creosote

DC698,<br /><br />A couple of questions:<br /><br />I now frequent my cottage most of the year and burn about 25 fires (about a 3/4 bush cord of seasoned hardwood) per year.<br /><br />I used a chimney brush to clean the chimney and got about 4 to 5 coffee cans of debris. I used to bank my wood stove 'till I found out better.<br /><br />The first couple of times I used the woodstove after cleaning, I would bank it. I would get this horrible tar like substance coming out the seems in the pipe on the inside of the cottage. The firt time this happened I was there alone and thought the cottage was buring down. The only place I thought that was burning was the attic. It was fine and the burning smell came from the creosote (?) coming out the pipe seems.<br /><br />Now I make a proper hot fire and this problem is gone. <br /><br />Should I be concerned?<br /><br />and <br /><br />Are my stove pipe segments in upside down?<br /><br />Tx.<br /><br />Joe
 

DC698

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Re: Chimney Creosote

Joe, The tar like substance was definately the creosote heating up enough to melt through the stove pipe seams. If you can, I would replace the stove pipe as it sounds like there is 3rd degree glazing inside the pipe. Did you notice the leakage through just the black stove pipe? Or throughout each pipe section of the entire flue? The stove pipe should be male end DOWN or in other words, crimped end down. This eliminates water penetration on the outside of the pipe (If it gets past the cap on top -- Should always have a cap on top) and eliminates the leakage of creosote -- which is what sounds like in your case. You may have burnt off most of the creosote inside the pipe also. Give it a visual check and see. But with all the creosote leakage on the exterior of the pipe, you may want to replace it anyways to avoid smelling burning creosote when you use the stove. --Derek<br /><br />PS: SS Mayfloat, an 8x12 flue, by venting standards, is usually too big for the typical woodstove. Although most stoves are installed into a masonry chimney that have 8x12 or 12x12 flue liners and they will work fine, they are too large for most liquid and solid fuel burning appliances. An 8x12 flue has 96sq inches which would be too large an area for a typical 6" woodstove venting through it which in theory is what causes the rapid loss of flue gas temperature and causes the creosote build-up (In short thats what happens..along with a bunch of other chemical reactions). --Sorry so long!
 

JasonJ

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Aug 20, 2001
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Re: Chimney Creosote

My temp gauge is on the pipe, at the 1st elbow. The pipe goes up out of the stove about 2 feet, elbows towards the wall, enters the wall, elbows back up and out of the roof. The stove is mounted in a corner, and there is a false wall the hides the pipe. Everything is recent, nothing old about the system, and it is regularly maintained. I try not to bank the fire to burn all night, usually whoever gets up in the middle of the night for bathroom action has to toss a log or two in. If it dies, it dies, I'll just restart it in the morning.
 

steam_mill

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Re: Chimney Creosote

DC698,<br /><br />Thanks for the info. You have confirmed my belief that the stove pipe is in upside down. Luckily the rest of the pipe(non black?) in the attic and out in the outdoors does not have any creosote leakage.<br /><br />Unfortunately, I've looked for someone to clean/inspect/repair the chimney but no such organization exists where my cottage is located so I am pretty much on my own.<br /><br />With only 20 to 25 fires per year, burning hardwood only, how often should I clean the chimney?<br /><br />Tx.<br /><br />Joe
 

one more cast

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May 6, 2002
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Re: Chimney Creosote

When I burned wood (24 cord a year) I had only a 6" x 8' stainless insulated pipe. If I didn't burn it out every day it would plug almost solid in 2-3 weeks. And that was burning all seasoned hardwood. A thin layer of that shiney hard creasote when ignited will expand enough to plug the pipe and when it burns it will creat enough draft to make a stove sound like a freight train.
 
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