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Opinions on smoke color from chimney

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by wahoowad, Feb 4, 2006.

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  1. wahoowad

    wahoowad Minister of Fire

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    Ordinarily I burn a load or two in the evening for a little warmth and mood. Today (being a Saturday) I thought I would try ot run it all day without reloading it every 2 hours. I packed it full, let it char the logs a bit, then closed down the primary air control over the course of half an hour. Anything below 25% stops active flames. I thought I'd check out my chimney and see what kind of smoke I was getting (usually it is none). See attached.

    It looks pretty white to me, slow plumes of white smoke coming out. Do you think this type of smoke promotes creosote buildup? I can open the air supply to 50% and get adequate flames and near zero smoke but then I go through logs every 2 hours. I'm trying to get a project done out in my shop without actively tending the fire all day.

    The glass door lets me see that the bottom logs are glowing red on the bottom. No visible burning elsewhere and the firebox is fairly packed with an assortment of decent hardwoods.

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  2. roac

    roac New Member

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    I dunno but if I'm your neighbor I will think you are smoking up the neighborhood. As far as creosote I'm sure more would be formed but just how much is hard to tell. Need a flue thermometer to be sure. But I'm sure running it like that every once in awhile isn't going to make that big of a difference in the amount of creosote you form in the chimney.
  3. begreen

    begreen Mooderator Staff Member

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    Looks like the wood needs to char a bit longer. With a full load, this will take 15-30 minutes. Normally, if I see white smoke like this coming from the chimney it means that either my wife just threw on another log or the fire needs a little more air. The air intake control is pretty sensitive. Sometimes just a tap will make a nice difference in smoke reduction. Ideally you want slow, lazy blue-orange flames. What kind of wood was burning at this time? That will affect burn times as well, but most of us are only getting 2-4hrs per load with the 3CB. The firebox is too small for much more. However, our stove is still usually at about 350 after 4 hrs, so there is heat, just not the 500-550 heat at peak burn.
  4. wahoowad

    wahoowad Minister of Fire

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    i think I've got a few pieces each of locust and poplar. I thought the poplar would burn a bit quicker,maybe produce a little more flame to help the locust along. man, I'm hoping I don't have to be that sensitive to the woods I'm burning. I just wish I could close it down more - anything with a active flames, even lazy flames, seems to only get me into the 2 hour range.
  5. Todd

    Todd Minister of Fire

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    This is one of the reasons I'm switching my non-cat stove for a cat-stove. As long as the cat is lit off the smoke from a smoldering fire like your picture should be burned off. Less pollution more heat, and cleaner chimney I hope?
  6. Sandor

    Sandor Minister of Fire

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    The cat on my stove seems to glow red when the air is turned pretty far down. 3/4 or wide open, no glow..... so I guess the firebox is efficient with alot of available air. The manual said to never run the stove wide open anyway.

    Wahoo, I had the same issue with the two Regency's I had. Fast burn = no smoke= 2hr burn. Slow burn=smoke=black glass.

    That being said, the VC Resolutes burn quite some time from a load, but I think thats from being able to fill it to the gills with the top load feature. And the secondary burn process seems quite efficient.
  7. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    And if it is only one color of smoke it is coming from a radiant stove. Convection stoves generate tri-color smoke.

    And then there is the difference between the smoke from hand split wood and machine split wood...
  8. precaud

    precaud Minister of Fire

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    Methinks you should pay less attention to what's coming out the chimney and more to what is going on inside the firebox. If you don't have a secondary burn happening during a low firing rate burn, the stove isn't operating as it was designed to, and it really doesn't matter what color the smoke is in that case.
  9. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    Which way should the smoke spiral here in colorado? KIDDING, but on this note, if you have a screened cap, you will soon find out if your burning to low, i cant burn my stove much lower then 75 percent to get secondary burn to happen. If you are using a jotul 3cb you shouldnt see any smoke when burning right. Except when adding wood.
    A percieved disadvantage ( i dont consider it a disadvantage at all) of a non cat stove is that you have to burn it pretty wide open to get it to burn properly, and chimneys play a important role in all this too.
    And i completly agree with precaud.
    Ryan
  10. wahoowad

    wahoowad Minister of Fire

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    oh no, my smoke was not spinning in either direction. Should I take the stove back?

    The glass got really dark by the time that load burnt down - I guess no closed damper / long burns for me. I did get 4 hours out of it but doesn't look like a clean burn.
  11. begreen

    begreen Mooderator Staff Member

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    Yes, that doesn't sound right. The glass usually doesn't soot up unless there is a log burning too close to the glass (ceramic). And even then the carbon usually burns off by the time it's ready for a refill.
  12. elkimmeg

    elkimmeg Guest

    ok in the northern hemisphere as the smoke ascends it is effected by......
    Holly crap I can't go there
    got in enough trouble the last time hey hey hey what did I say
    Btw did you notice the spiral pattern as it exited your chimney http://www.hearth.com/econtent/index.php/forums/smileys/#

    back to the original post: At times white smoke is not a good sign. Why? Because steam is also white in color.
    So how does steam enter into your smoke exhaust, too much moisture in your wood. It is possible that your
    wood is not a dry as you think. In a rush to damper down you are still vaporizing the wood moisture. The whiteness in
    your smoke, is because it is mixing with steam. I also believe you should be controlling your initial burn with your air inlet.
    I think you are rushing the dampering down. It would not hurt, probably improve your efficiency, to reduce the air.

    Here is
    an example of my thinking. I start the fire damper full open position air full open. The kindling starts a decent small bed
    of coals. I add 3, 2" splits. I wait for them to fully catch at least 10 minutes. I then add my normal size splits say 2 or 3 more
    pieces. wait 10 more minutes for them to be fully in flame. At that point I may cut the inlet air flow in half. I am also watching my surface thermometer. I want to bring the stove up to 450 to 550. AT 500 I may cut the air to 1/4 open. Again watching the thermo
    At this time I may add a few more splits to fill up the fire box wait 10 minutes for the new wood to catch. Watching the thermo as it approaches 550 plus, then damper down, but increase you inlet air to 1/2 open. The temperature may back down some. If back
    to 500 you have a choice leave everything alone and generate decent heat or go to 1/4 open inlet air. Again this should back off
    your temp to somewhere between 400 and 450. If satisfied with your heat output, you arrived at optimum burn, and a setting that will prolong a productive heat output burn. If it drops under 400 and there is plenty of wood in the fire box, increase the inlet air to 3/8 and see it that gives you a decent burn rate. As you see there is a little more effort and user corrections involved to learn and find longer heat productive burns. If your wood is a bit wet, then you may have to increase the airflow more open and longer.
  13. belsenj

    belsenj New Member

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    I know I'm a newbie here, but it sounds like you are burning wet or green wood,
    wahoowad? When I drive up to my driveway, I always look to see what smoke is
    coming out of my chimney. When I can't see it but I can I can smell it faintly,
    I know it's burning right.
  14. wahoowad

    wahoowad Minister of Fire

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    I had done the gradual dampening down as Elk suggested - that was something he had mentioned on a previous related post. I've been using what I consider dry wood. I have enough that I don't need to burn anything else, occasionally skipping over a log that feels heavy or seems wet that somehow appears in my 'dry' stack. I've tried this before with store bought kiln dried wood with the same results, although I do recall my very first burn had flames with a 'closed' air supply because that really surprised me (I was trying to kill the fire). I've tried using an incense stick to check for leaks - none.
  15. elkimmeg

    elkimmeg Guest

    Sorry I repeated the information again from a prior post.

    Ok At times when I damper down smoke does not vanish instantly.

    Another thought if you live East of the mississippi R we have had unusually warm winter so far.
    This is not near normal. This could be effecting many peoples stoves. If a new stove this year or new to wood burning, this is not normal. Colder weather does help produce stronger drafts.

    Point being, it might not be the stove, the user, the wood moisture, but it is due to a freak in nature.
    This winter might not be the one to judge stove preformance
  16. Hokerer

    Hokerer Member

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    I thought it meant that he just elected a Pope
  17. Rhone

    Rhone Minister of Fire

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    With my stove & secondary burn, it makes a word of difference if I pack it to the gills. The closer I get my wood to the secondary burn, the better, and longer, it burns. Unfortunately comparitevely my unit is big (my unit takes 8 log splits to pack it, has 10 hour burns) so this may not apply to you. The higher I can pack it, the better. The best burns, is when I've packed it in such a way that the wood is literally just barely touching all the secondary baffles. Within the hour, the wood has burned some off and shrunk and is 1/2" or so below it and my secondary burn is going freely, as the flames only need be 1/2" to keep it going. I can then lower my unit down to 20-25% depending on the temp, and the secondary burn goes 100%, and no smoke at all... just little heat waves. If I load it up, so my wood ends 3" below the secondary burn when I start a fire, the secondary burn has a harder time starting and when the wood shrinks and drops down, now my flames need to be a couple inches high coming off the logs to keep it going. That means, I need to have more air.

    I recall a poster saying in his manual for his Hearthstone it says to keep the wood a couple inches below the baffles. I think they're delicate, Hearthstone didn't want people jamming wood into them, but on my unit the success of my burn is based on how high and close I can get my wood to the baffles. The more I can, the better the burn. I also wait until the wood is well chared before turning it down.

    Not to say it may be an atmospheric event. This weekend something really strange happened to me. Last night, I tried to light a fire. It was around 40 degrees, plenty for drafting, but it sure was acting like it was 55 degrees outside. It was as if, there was an atmospheric condition and the air was heavy and trying come down my liner because there seemed to be a battle going on between my fires draft and the air outside. I had to leave the door open a crack for over an hour, and even with it like that, the fire was just barely able to sustain itself. It was windy, which played some part, but I've had fires in worse wind than last night and had no problem previously. I've never seen that with my insert before, my previous stove didn't have a window so if it was happening, I never saw it. This morning, was 30's outside and same thing.
  18. elkimmeg

    elkimmeg Guest

    Rhone start checking your flue for build up or blockage and your connector pipe, If this problem persist
    Also soot ash impeding the inlet air passages.
  19. Rob From Wisconsin

    Rob From Wisconsin Minister of Fire

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    I would personally have to peronally disagree with using this approach on an EPA
    Non-Cat stove. I have tried this on both of my stoves, and found it to actually generate more smoke in the early phases of burn (up to an hour). It almost seems
    that the excess smoke that is being generated by the extra wood can't be sufficiently
    combusted in the reduced space above the wood - not enough air above the wood
    to support proper mixing?? As a general rule, I have found that about 1/2 - 1/3 of the
    firebox should be left "open" to support good mixing/combustion.

    P.S. - Swirling/Rotating smoke?? That is silly... everyone knows the world is flat....

    Rob
  20. pmac

    pmac Member

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    I'd agree with this - if I pack the stove before bedtime, I usually have to do this an hour ahead of time, so I have time to leave the air wide open and get the logs to catch good, before turning it down for the night. Up until then, it could be smoking for a while before getting hot enough to turn the air down.

    On the other hand, during most of the day, if the stove is about 1/2 full and hot, I'll just occasionally throw a new log in and rarely see any smoke after a minute or two...
  21. Sandor

    Sandor Minister of Fire

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    Pmac and Rob, I agree 100%.
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