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Why is my wood stove smoking so badly?

Joshua Frank


Joined: Sep 26, 2013
Posts: 3
I just moved into a house in the Catskill Mountains of New York, and it's getting cold, and there is no central heat! There's a woodstove, but I'm finding that I can't use it because it smokes so much. No matter what I do, every time I open the door to add wood or stoke the fire, so much smoke pours out that it really pollutes the air in the house. This is a problem, because we've got a ton of wood and we really need to be able to burn it to keep the house warm.

The stove is a Jøtul F 400 model, if that is helpful, and I'm attaching a picture below. That 90 degree bend in the stovepipe can't be good, and there's another 90 degree turn to send it back up the chimney, which is 3 stories high and stone and massive.

Things I have tried:

  • Having a chimney sweep clean the stove and chimney. He said all is well (doesn't mean he's right, but that is his job).
  • Starting a small fire from kindling and waiting for embers before adding more wood.
  • Opening the door a crack and waiting for the temperature and pressure to equalize.
  • Opening the cleanout door under the unit, to allow air in from the bottom to create an updraft.


  • But nothing works: any attempt to open that door billows smoke into the room.

    Is there anything else to try, or is something just wrong with this setup?



    [Thumbnail for 2013-09-26 08.16.41.jpg]

    Craig Dobbelyu


    Joined: Dec 22, 2011
    Posts: 932
    Location: Maine (zone 5)
        
      30
    Sometimes it has to do with the house being a partial vacuum. When you open the stove, the difference in air pressure forces smoke into the room. If you open a widow just a crack before opening the stove, you may alleviate this issue.

    Also, Open the flue all the way for about a minute before you open the door. (all the way to the right) This will help create a better updraft through the stove and up the chimney as well as making the fire a little hotter and thus, less smokey.

    Burn only clean DRY wood. Wet wood will always make more smoke and the water vapor slows the exhaust of smoke up the chimney.

    Don't stack the wood close to the front of the stove. Burning the fire in the rear of the stove keeps the smoke flowing up the chimney.

    If all tat fails, try opening the stove door only a crack for a minute or so before fully opening it. The smoke may be flowing in one direction with the door closed and then in a different direction with the door open. Opening the door suddenly will disrupt the flow of smoke and may cause it to waft out of the stove. Move slowly and you likely have better results.

    I don't know if your stove has a side door but if it does, use it. They tend to smoke less.

    Jotel has a lot of good info on their website... including videos demonstrating the use of these stoves.

    Best of luck.

    Make sure your smoke detectors work.

    Better safe than sorry.


    "You may never know what results come of your action, but if you do nothing there will be no result”

    -Gandhi
    Joshua Frank


    Joined: Sep 26, 2013
    Posts: 3
    Hi,

    Thanks for the info. Here's what I have observed, relevant to your suggestions:

    Sometimes it has to do with the house being a partial vacuum.

    Interesting. I can't imagine this creaky old place is sealed tight enough for that, but I'll give it a try.

    Open the flue all the way for about a minute before you open the door.

    There is no flue control! There's a damper, which I open before adding wood, and there's the cleanout, which I also open. The fire clearly flames up, but the smoke still pours out. I wonder if the missing flue control is a sign of a botched job. Or maybe it's just always open.

    Burn only clean DRY wood. Wet wood will always make more smoke and the water vapor slows the exhaust of smoke up the chimney.

    I think the wood is pretty dry. The guy who supplied it swore up and down that it's been seasoning for years.

    Don't stack the wood close to the front of the stove. Burning the fire in the rear of the stove keeps the smoke flowing up the chimney.

    This is hard to do, because I'm trying to close the damn door as quickly as possible because of all the smoke!

    try opening the stove door only a crack for a minute or so before fully opening it

    This is exactly what I do, but once I open it, it still smokes.

    Jotel has a lot of good info on their website

    I spoke to the local distributor, and he thinks there's an opening somewhere in the chimney, in the basement, that's causing a downdraft. So I've called the chimney sweeps again. This seems related to your first suggestion though: something is causing the pressure inside the box to be higher than the outside. I hope someone can track it down.

    Cheers,
    Josh
    Craig Dobbelyu


    Joined: Dec 22, 2011
    Posts: 932
    Location: Maine (zone 5)
        
      30
    I thought of a few other things:

    If you go into your basement and can see the base of the chimney, there should be a little metal door. Make sure that sucker is shut tight. While you're there, take your camera and snap a few pics up inside the chimney. You may find a blockage that was somehow missed. Aim straight up and use the flash. You'll be surprised what you might find. If all is clear, you should have a tiny picture of the sky.

    The other thing is that the rise from the stove to that first ninety degree bend is pretty short. Maybe that could have something to do with it. that being the case, remove that piece of pipe from time to time and clean it out really good. If you're getting a lot of smoke, you may also be getting a lot of creosote in there.

    Is the top of the chimney higher than all the surrounding structures? Maybe you're getting some kind of downdraft caused my the wind outside.

    These things can be a pain in the ass to deal with when all you want is a nice clean warm fire. I know how it goes. I bought an old farm house with a good Jotul stove and it took me a good two heating seasons to really get the hang of the dynamics.

    Here's what I would do next time I started a fire in your stove.

    Build a small fire from kindling and slowly add small wood to it to get a good hot fire going. When you're ready to add more wood open the damper all the way. Leave the clean-out closed. As long as the fire gets hotter, you know the damper is working right. Now, close the damper and let the fire die down for a minute. Now open the clean out only ( just a crack). If the fire heats up again, you know that there is no blockage between there and the box. Now close that back up. So far so good.
    Now be sure that the clean-out door in the basement is tightly shut. Crack open a window in the same room as the stove and note the draft. Is air coming in or going out? Neutral? Now open the damper, wait a minute and then open the stove door. Take note of the smoke and also see if the draft near the window changes too.

    I hope this helps to narrow down where the issue is.

    Bill McGee


    Joined: Mar 04, 2013
    Posts: 172
    Location: Southeastern Connecticut, USA
        
        3
    Joshua,

    I did a search of "Jotul F400 problems" The website www.hearth.com and others have discussions on it. Since the Chimney sweep is returning can you discuss lighting a fire while he is there. Good luck. Tell us how it works out.

    (The stove has a bottom air feed, No chance that is blocked? If you burn a single sheet of newspaper, and add newspaper knots does it smoke up the house)?
    Joshua Frank


    Joined: Sep 26, 2013
    Posts: 3
    @Bill: The air feed seems to work, because I can see the fire glow brighter when I move it from closed to open. But pretty much any fire of any size does smoke up the house.

    @Craig:

    If you go into your basement and can see the base of the chimney, there should be a little metal door.

    I don't see one, and the guy who installed it says that this has no such thing. The stove apparently uses its own exhaust pipe, and it only runs up, not down. What is that basement door thing *for*?

    remove that piece of pipe from time to time and clean it out really good

    I just had the whole thing cleaned by a chimney sweep and he says it's okay.

    Is the top of the chimney higher than all the surrounding structures?

    No, although we're nestled against a ridge that rises steeply away from the house, so who knows what the air currents are like.

    I'll keep trying your suggestions and see what else I can learn. Thanks for all your help!

    Cheers,
    Josh
    Craig Dobbelyu


    Joined: Dec 22, 2011
    Posts: 932
    Location: Maine (zone 5)
        
      30
    Joshua Frank wrote:@Craig:

    If you go into your basement and can see the base of the chimney, there should be a little metal door.

    I don't see one, and the guy who installed it says that this has no such thing. The stove apparently uses its own exhaust pipe, and it only runs up, not down. What is that basement door thing *for*?



    In my set up, my chimney has two separate exhausts. One is designated for the oil burner which runs my forced hot air heat system. The second one is designated for the wood stove. Each of these chimneys has a clean out door at the very bottom of the chimney in the basement. I suspect this is in case anything falls down the chimney (birds, meteors, ash, soot). When I sweep my chimney I do it from these doors. All the chimney junk falls down to that spot where it's easy to vacuum it up.

    So if you remove that "L" pipe on your stove and reach in to the stone chimney, are you saying that there is no way for anything to go down? Only up? There may be too many bends to effectively get a good updraft.
    If the chimney is three stories tall and all stone, it could be that the chimney isn't hot enough to create the updraft. How long are you burning a fire? What kind of wood? Aside from being well seasoned, is it stored away from wet areas and out of the rain? You might need to get a good hot fire going for a good day or so to dry out the chimney fully. Is there a cover vaulted over the chimney top to keep rain from falling down inside?


    If possible, you may try getting the chimney extended high enough to clear the wind/air disturbance that seems to be forcing air down.


    I have to think that the previous owner must have had a way of making it work right. Is there any sign that the house has smoke damage to any degree from this behavior? Can you contact the previous owner and ask questions?
    Karl De Pauw


    Joined: Feb 20, 2013
    Posts: 23
    Location: Aarschot belgium
    your exaust pipe does it turn up in the chimmeny or strait in , in the second case it micht go in to deep and by doing so create a to small gab to get a good exaust flow into the chimmeny

    an other option is to make a new conection just under the ceiling go up from the stove and enter there normaly the stove pipe chould create a stack effect to not have a smoke back
    plus recuperating more heat for the room

    kind regard karl

    yolo, live for today but make sure that the one's you poducede can have a live too
    R Scott


    Joined: Apr 13, 2012
    Posts: 2308
    Location: Kansas Zone 6a
        
      28
    Well, I know nothing about that stove except the picture and that Jotul usually has a great reputation. The stove looks really shallow with a HUGE door that appears higher than the flue out the back--I can't see how it could NOT smoke up the house when you open it.


    "You must be the change you want to see in the world." "First they ignore you, then they laugh at you, then they fight you, then you win." --Mahatma Gandhi
    "Preach the Gospel always, and if necessary, use words." --Francis of Assisi. "Family farms work when the whole family works the farm." -- Adam Klaus
    Timothy Reeves


    Joined: Oct 23, 2013
    Posts: 8
    Flew/chimney needs to maintain 300-600 degrees for smoke to exhaust out of your wood stove. Your massive chimney is 3 stories high..Its robbing all the heat needed and stalling out the smoke ..With a cold flew its going to take the least path of resistance and with a 14x28x36 firebox with the 6" flew mounted on the rear with 90s on it and a load door almost the size of the box?..I'm not sure what to tell you.

    Michael Schuiling


    Joined: Oct 24, 2013
    Posts: 4
    Jotul is an outstanding scandinavian stove company that has been around a LOOOONNGGG time. Their stoves are exceptionally fine. A couple of observations that strike me:

    1. This is a large stove. Designed to heat a large area (1,600 sq. ft.). This stove has a huge firebox!

    2. The chimney is huge!

    3. You mention 'opening' the damper/air inlet/ draw control prior to opening the door.


    These 3 issues are a major cause (and most common) of smoking. If the chimney is an exterior chimney (it appears to be) this is compounded by the cooling effect of the outdoors.

    With stoves this large, it is easy to want to load them up and choke them down to get long burn times out of them. Smoke is a product of incomplete combustion… If the stove is oversized for the area that it is heating, people have a tendency to choke the air off to cool the room. This forces the stove to run inefficiently and cooler. The flue should run about 400 degrees constant to keep the smoke moving up the chimney. If it isn't that temp. the exhaust cools and sticks to the inside. When you open the door, the pressure in the firebox is high. But, the cooler / heavier air in the chimney is push the hotter air out of the feed door… Thus, the smoke in the room.


    Suggestions:


    1. Get a smaller stove. It is better to get a smaller stove and run it efficiently (and get the proper btu's out of it) then to get a big stove and keep it reigned in all the time.

    2. With the Jotul; burn smaller, but, hotter fires. This may keep the room temps in a comfortable zone and keep the flue temps higher allowing the exhaust to make it to the top of the chimney and keep the pressure up in the chimney.

    3. If you are forced to choke the air down; before opening the feed door, open the air inlet all the way, and get the wood to a free burning stage before opening the door. This will increase the heat in the chimney and increase draw.

    4. Think about the chimney as the 'damper'. the chimney is what controls draw… If it isn't drawing air out of the stove, you have no efficiency… and that is bad… and dangerous.


    Hope this helps.

    Frostymedic
    K Nelfson


    Joined: Nov 07, 2012
    Posts: 124
    Joshua Frank wrote:

    Burn only clean DRY wood. Wet wood will always make more smoke and the water vapor slows the exhaust of smoke up the chimney.

    I think the wood is pretty dry. The guy who supplied it swore up and down that it's been seasoning for years.


    Wood that isn't dry will sizzle. You should get a thermometer to keep track of the flue-gas temperature. If everything is right, you should have consistent hot gas flowing up the chimney, 600 oF or so. Adding wet wood will drop the temp in the chamber by 100 oF or more.

    Consider batch burning and upside-down fires. The normal MO for wood burners is to create a small fire and then throw some cold wood on top. The cold wood condenses the hot gasses coming off the small fire, causing smoke. And as the surface of the new logs starts to get up to temp, the cold interior cools it, also causing smoke. If you put the really big logs on the bottom and kindling on top, some of the heat conducts down, preheating the wood that will burn next. Makes for a smoke-free fire.

    People with masonry heaters and rocket type configurations favor batch burning. Basically, you heat up everything and it keeps heating the room while the fire is out. Maybe you could do something like that.

    Annoying as this problem is, I'm sure you can eventually make it work.

    M Foti


    Joined: Oct 21, 2013
    Posts: 164
    Location: western n.c.
        
        5
    I've been building outdoor furnaces for a while now, I really think the problem is the overall design of the stove coupled with your chimney... as pointed out earlier, that stove is shallow with a big door, it's gonna smoke unless the chimney is really sucking it up. I don't really put any stock in "it's an X brand" even a mercedes can be a clunker. My opinion is you have 2 options at this point, install a double or even triple walled flue for the whole run of your chimney, or get another wood heater. I'd personally be looking at a larger heater with a deeper design (not shallow) with a rise in the body of the stove before the flue pipe goes out, and with a door that is well below the flue pipe.

    Larger heaters aren't as "efficient" but depending on your situation, efficient isn't always best. My current furnace uses quite a bit of wood to heat a small space, BUT... I only have to stoke the fire once a day and run with the dampers fairly well closed. I do have to open it up periodically to help get rid of the buildup, but it's better for my lifestyle than having to feed one every couple of hours.

    Ideally, you would do a triple walled flue pipe (this also increases the safety factor exponentially) with a better designed stove. Without changing something, I don't think you'll ever be happy with the results from this one. 3 stories is a long run for a flue pipe....


    There was one more idea mentioned that would probably work as well, someone mentioned changing how the flue exits the stove and have it go up a bit before it turns into the chimney/wall... That may help, probably would, and would be the cheapest route...


    Ajila Ama Farm Western North Carolina
    www.facebook.com/ajilaama
    Roy Clarke


    Joined: Feb 05, 2012
    Posts: 121
    M Foti wrote:Larger heaters aren't as "efficient" but depending on your situation, efficient isn't always best. My current furnace uses quite a bit of wood to heat a small space, BUT... I only have to stoke the fire once a day and run with the dampers fairly well closed. I do have to open it up periodically to help get rid of the buildup, but it's better for my lifestyle than having to feed one every couple of hours.


    Recipe for disaster IMHO. Efficiency in converting wood to heat is everything. Anything else means fuel will wander off as smoke and condense where it can, forming tar. This is bad, especially when it catches fire. I think it was Dale mentioned in another topic, burn small intense fires. That way you need only open the door when all flame has died, and you are left with only charcoal. Yes you have to feed it often, but that's the nature of the beast. If you want to feed it only every few or several hours you need a masonry or other high mass stove.
    Michael Cox


    Joined: Jun 09, 2013
    Posts: 876
    Location: Kent, UK - Zone 8
        
      21
    It is hard to tell from the pictures:

  • Is the chimney internal or external to the building? if external the stone may be cold.
  • is the stone chimney lined with a metal flue liner? An insulated double walled flue liner keeps the temperature of the gases high and drafting strongly
  • when your stove is burning normally and the door is closed does your chimney smoke? An efficient stove shouldn't smoke so this could indicate some other problem. Likely causes are damp wood, overly damping down the draft to the fire, low temperatures in the firebox, and damp or partially seasoned wood.


  • Someone has already suggested adjusting how you feed the fire to facilitate batch burns - this is a pretty good idea. Load the firebox up high and don't touch it again until it has stopped flaming and you are left with a nice deep layer of glowing embers. Open the stove at this point and it shouldn't smoke. Poke the embers around to open them up and add you next load of logs on top.

    Other possibilities - are you also having trouble lighting the stove? If so you may have a temperature inversion where the inside air temperature is cooler than outdoors. You chimney draft is having to fight a downdraft.

    Could the exit of your flue be blocked or restricted? Restricting flue diameter at any point along its length can cause drafting problems. Your chimney sweep may have cleared the run of it but not looked at the cap on top? Generally any kind of flue damper is a bad idea - they can lead to smoke backing up into the room, or worse still carbon monoxide, especially if they are closed down at night while the fire is burning low.


    Ultimately my money is on the wood being damp or unseasoned.
    http://www.woodstovewizard.com/seasoning-firewood.html

    Mike
    Roy Clarke


    Joined: Feb 05, 2012
    Posts: 121
    Michael Cox wrote:
    Someone has already suggested adjusting how you feed the fire to facilitate batch burns - this is a pretty good idea. Load the firebox up high and don't touch it again until it has stopped flaming and you are left with a nice deep layer of glowing embers. Open the stove at this point and it shouldn't smoke. Poke the embers around to open them up and add you next load of logs on top.


    Loading the firebox too full will cause problems. Once he wood is heated and gassing well, there is too much fuel for the available air, so the excess goes up the chimney and condenses. It may also make the room too hot from the high heat output. Leaving space and ensuring the air/fuel is balanced will produce the most heat from the fuel, and as you say, open the door only when the flames have died.

    PS I wouldn't leave the door open even when the flames have died, until the smoking problem has been fixed. The same problem may exist, but instead of smoke, the room is filling with carbon monoxide. Leaving the door open could cure ALL your problems.
    Chris Fabe


    Joined: Feb 01, 2014
    Posts: 1
    I have a similar stove, the jotul f500, and had a similar problem. I discovered that the elbow had failed and split apart..causing insufficient draft. I couldn't get the wood to burn very well and tons of smoke was coming into the house every time I opened the door. After replacing the elbow (for about 15 bucks) I'm back in action. No smoke and wood burning much better.
    I also wouldn't use the ash door for draft..I was told that using the bottom door causes a "flame thrower" effect and can heat your stove up too quickly. If I need more draft for some reason I open the side door. Not sure if you have one on that model though.
    Hope your fix was as easy as mine...happy burning!
    Steve Barson


    Joined: Feb 02, 2014
    Posts: 2
    It is very rare that there is a problem with the stove, it is always the chimney or wet wood, yours is not drawing properly. The chimney sounds high enough so it will be:
    . Air is entering the chimney elsewhere which is providing an easy route, rather than being pulled through the stove. Check for leaks, particularly if there is an ash pit below, or if the chimney is being shared with another opening.
    . If the chimney is not lined you are going from a 6" flue pipe into a much larger void and losing suction. The answer to all your problems will be to drop a flue liner down the chimney and connect it to the flue pipe and the top of the chimney.
    . The 90 degree angles are really not helping. If you have to have them, take the flue pipe vertically off the top of the stove for as far as possible (keeping a safe distance from combustibles) before going through into the chimney void.
    . Don't burn wood which is >20% moisture, preferably <15%.

    Hope this helps.

    S
    Steve Barson


    Joined: Feb 02, 2014
    Posts: 2
    Just noticed the reply above about leaving your door open. DO NOT LEAVE THE DOOR OPEN. Sure, it will burn the fuel but you could be putting huge amounts of CO into the room. 400 ppm of CO can kill you, a solid fuel stove can generate 80,000 ppm. I make stoves, not CO detectors, but everyone who has a wood burner should have a co detector.
    Just another thought on the smoking stove. If you live in a valley or have overhanging trees etc you may have a downdraft coming down the chimney. A cowl will help reduce this but you should ask an export to have a look at it.
    S
    Dc Taylor


    Joined: Mar 03, 2014
    Posts: 15
    Location: Livermore, CA
    You need a new chimney sweep! One who is certified by CSIA, and I mean the one who is working on the chimney, not just the owner being certified. First of all, no single chimney should ever vent two or more appliances. Second, I'm betting if the masonry chimney were to be lined with an appropriately sized and insulated liner (with an appropriate clean-out tee at the bottom), you would be having zero problems. Jotuls are excellent units. Your problem is in the chimney.
    Jim Fisk


    Joined: May 28, 2014
    Posts: 4
    Location: Smoky Mountains of E Tennessee
    Funny but I don't think anyone has mentioned that lime leaching out of the chimney and running down the inside. My money is on an amateur built chimney. Seen lots of them. In my experience JUST a ss liner can double or triple your draft. You are suffering from a sick draft. With a good draft you could run that stove open front fireplace style and never get smoke. A modern gasifier stove could help greatly in terms of efficiency (sorry Jotul) BUT any stove is only as good as the chimney will allow and a ss liner does wonders. 500.00 to 1000.00 off the internet depending of course on your chimney height and install has always been a breeze if you don't mind heights. Figure half a day if you are into do it yourself as I surely am. (that way I have no one else to blame and that's the way I have always liked it Be sure and get an install kit with it.


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