Brown smoke?

Discussion in 'Modern EPA Stoves and Fireplaces' started by jtstromsburg, Jan 13, 2020.

  1. jtstromsburg

    jtstromsburg

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    I’ve cleaned my chimney twice this year already(the first being because I didn’t do it since last spring), and I’m looking for help on what are my potential causes of creosote? I burn hot, or as hot as I think is safe. STT of about 5-600 usually at early stage of burn once set. I do have a combustor in place and use it correctly as far as I know. I did just change my single wall pipe from top of stove to wall thimble from a up and 90 to up-45-45 thinking this would help flue temps. I have a clue temp gauge 18” above stove and it reads between 450-500 at early burn cycle time period, and I wait about 15-20 minutes for my combustor temp probe to show 800 or higher before closing the bypass. I still find the pipe near the horizontal thimble to be substantially cooler than the gauge below it about 30”?
    And just now, I was outside after starting on a bed of coals, and had heavy brown smoke? My wood could be better and will get better as I’m starting the three year plan. Is the brown smoke a sign of wet wood?
    I didn’t snap a pic of the smoke, but here’s my pipe as it is currently. [​IMG][​IMG]


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  2. jtstromsburg

    jtstromsburg

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    And here’s a pic of chimney cap after setting controls how I think they should be.
    [​IMG]


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  3. BDF

    BDF

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    Dark smoke is absolutely a sign of a wood fire burning 'dirty' and making some, maybe a lot, of creosote.

    If you just reloaded the stove, it is normal for it to produce some smoke until the firebox comes up in temp. and the combustor is able to efficiently burn virtually all of the smoke. If you get a chance to look at a combustor w/out any type of cover, it is quite common for some section(s) of the combustor being 'lit' (red or hotter) while other portions of the combustor are stalled and passing smoke. Again, this typically occurs before the fuel in the firebox is cold and the combustor is just starting to light or re- light.

    Storing wood outside, as I do, exacerbates this whole problem because instead of the entire load of new splits having to go from, say, 70F to 250F, they may start out a lot colder. There is a big difference in how a stove, especially a cat. stove recovers after being loaded with slits from inside vs. outside. Unfortunately, I just do not have the room to store any appreciable amount of wood inside and re-starts after fueling the stove are corresponding slow or at least can be when outside temps. drop in mid- winter.

    Brian

     
  4. BDF

    BDF

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    That is pretty light smoke and not very dense at all- looks like mostly steam or water vapor to me. Perfectly normal and a clean burning stove.

    You have to 'read' smoke by the opacity of it and how it changes as it leaves the chimney. Smoke you can easily see through does not contain much particulate matter (soot, creosote) and that means the stove is burning clean. Also, as the smoke leaves the chimney if it dissipates into the surrounding air and seems to disappear, that means it was mostly or all steam. Smoke from a dirty wood fire is more difficult to see through and travels away without dissipating for a long way.... assuming light wind conditions. No fair trying to read smoke in a typhoon :)

    Brian

     
  5. jtstromsburg

    jtstromsburg

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    I should have got a picture of when I first did the restart as the smoke was thick, brown, and not transparent. But it’s good to know this last picture doesn’t seem too bad. I am able to keep a couple weeks of wood inside and think that should even help with drying a bit. I split a chunk and tested it when I made this post. It read 28% so got a ways to go. This wood was misty cut last spring or even early summer. I’ve got next years wood stacked and drying now. It was cut at the same time and most of it is top covered now.


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  6. lukem

    lukem

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    Blue or brown smoke is unburned fuel, white is steam. More smoke on a restart is normal, should be minimal once fully up to temperature....if not you have more smoke than your secondary burn / catalyst can handle. More smoke than it can handle could be a result of too much moisture, too much primary air, not enough secondary air, or an underperforming catalyst.

    This is all pretty general, but applies to every type of wood burning device out there.
     
  7. jtstromsburg

    jtstromsburg

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    Thanks!


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  8. moresnow

    moresnow

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    Sounds like your doing the best you can with the wood you have. As you get into better seasoned wood you will notice a difference in smoke at startup and a much easier burn to manage overall. It gets better!
    On another note. Any concern with the distance to the combustible above the pipe? Optical illusion? Looks a bit close!
     
  9. jtstromsburg

    jtstromsburg

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    Good catch on that. I didn’t install so not 100% sure, but I believe it works according to the manual. The sheet metal pan that helps catch the hot air to circulate with furnace fan is wrapped with pine. But the rear part is all sheet metal and bent to go up at an angle. The rest of the back wall is the poured concrete wall and then cultured stone. I have kept an eye on that spot since I first started burning the year I moved in. I feel better about it after I changed the pipe the PO had as it wasn’t attached to anything and each piece could just slip apart. He said he had that way so it was easier to clean but pulling a few little screws isn’t an issue for me.

    Thanks for the encouragement on my practices! Love this group


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  10. Kimberly

    Kimberly

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    If you do think the clearance is an issue, then you put a heat shield there with a 1" air space and you will be good to go.
     
  11. RGrant

    RGrant

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    My wood supply isn't good. It sizzles a bit at the start- and unfortunately I don't have too many options other than to use what I have. I use wood bricks to bring the overall moisture content down, but it doesn't change the fact that my wood supply could be better.
    Now- I almost always get a decent amount of brown smoke at the start of fires and more often than not when I do a full reload, but that usually goes away pretty quick, 25 minutes give or take. I've been a little nervous about creosote so I've run the brush through the chimney a couple of times and I'm not really getting very much of anything out. Just stay on top of it, and... well like me, I've got to establish a better wood supply. Working on it.
     
  12. Backwoods Savage

    Backwoods Savage

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    jtstromsburg sorry I did not see this earlier. One thing not commented on is the flue. You stated that the flue temp is much cooler above the temp gauge. Realize that the top of the horizontal will read a lot different than the sides. Something about heat rising... And for sure you will notice a big difference when you get really dry wood and your cat will last a lot longer too. Good luck.
     
  13. FatBoy85

    FatBoy85

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    Blue smoke is usually the sign of a hot or clean burning fire. If you burn in a bbq snd got everything set up right, dry wood and all , it should burn well and smoke blue smoke. That’s the best as far as the bbq’ers know and its only a blue tinge and running clear in opacity. :yes: If this is a catalytic stove... then I’m out of my expertise.
     
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  14. lukem

    lukem

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    Still unburned fuel.. when my boiler has blue smoke it means the fuel has bridged up and needs a poke to get the wood closer to the coals and get it burning clean again. Usually there is zero visible smoke....that's when I know it's running clean and hot.
     
  15. FatBoy85

    FatBoy85

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    I’ll have to keep that in mind. When I had my wood stove it was hard to see smoke after loading it up and giving it time to burn hot again. At least that told me my wood was fine. Would this apply to all wood stoves?
     
  16. lukem

    lukem

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    Yup.
     
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  17. RGrant

    RGrant

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    Sometime after my fire is established and my sizzling dies out, I run the stove hot, I get the stove temp somewhere in the neighborhood of call it 500 on the stove top, then engage the catalyst and take a little bit of time backing the air down. After that I only have the vapor lines- hopefully next year is a different story.
     
  18. billb3

    billb3

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    Yeah, brown smoke is usually unseasoned wood and/or poor fire temps.
    I have been burning some red maple that was split, stacked and put aside for someone 4 years ago that never came and got it. It has gotten rain wet and heavy and I'll have some billowing white smoke with a longer start up than I'd like.
    I don't think I've ever had brown smoke from the wood stove, just burning slightly green pine branches in a pile outside.
     
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