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Is my afterburner not working?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Skeezix_McGoo, Dec 4, 2011.

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  1. Skeezix_McGoo

    Skeezix_McGoo New Member

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    OK people, it's me again. Love my new Harman Oakwood, but it's not going right. It's a week old today, and I just got a rip roaring fire going (stovetop 600 degrees) and all is good. Now, when I push the lever to bypass the damper, I should not be seeing any smoke at all. But I go outside to look at the chimney AND ITS SMOKING LIKE A BASTARD. I mean huge, huge smoke! What am I doing wrong? If I get my initial fire any hotter before I bypass the damper, I'm gunna overfire the stove.

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  2. jdonna

    jdonna Member

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    Hey,

    As a former Oakwood owner, actually its sitting in the garage.

    Anyways, First question, how deep is your coal bed? You need a really good lump of coals 3-4 inches and it helps to rake some towards the throat opening of the secondary chamber.

    This stove likes well seasoned wood as well, you can overwhelm the secondary with too much smoke.

    Second are you letting your wood char good before engaging? Depends on your draft, but you can cut the primary air down some while in bypass mode.

    Also, each setup is different, but when you engage the bypass maybe you are turning your air down too fast.

    I would suggest adding a magnetic thermometer on the side of the fire dome right near the bypass handle. If the temp goes up beyond 500 degrees, you know that the secondary combustion chamber is working. People have reported 600-800 degrees.

    I know Harman also has some videos posted on their website for operation of the stove, and I am sure Branch Burner will chime in at some point too.
  3. Skeezix_McGoo

    Skeezix_McGoo New Member

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    Thanks Jdonna.
    I think that you have solved this (and I just finished watching my CD that came with the stove- for the 4th time I might add)
    My fire is hot as hell, but I did not build up a good bed of coals yet. I am working on that now. I will report back. This is becoming like an olympic sport. I'm going for the bronze!
  4. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Running a downdraft stove right on block fuel has got to be a real challenge. Those things like to have a coal bed of big chunks to get down and get it done.
  5. curber

    curber Feeling the Heat

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    Yep I'm learning with you. My stove sure likes the 24/7 burning better than the start up burn. But when you get it rite you'll get a nice hot long burn. I re-load the stove with a good coal bed and it just takes off. Pat
  6. branchburner

    branchburner Minister of Fire

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    That's the truth. Really needs the deep coals to run smooth. I think like BroBart said, Skeez, especially tough if using block fuel - if you also had some branch-wood or scrap hardwood or something similar, you could get a quicker coal bed. But once you have the coals, you'll be good to go. When it gets down near zero out, it should crank.

    My stove also prefers to be stuffed pretty full to keep the AB engaged and burning smoke-free. If I have a fire with just a split or two, even with a coal bed, the thing will crap out sometimes. That makes it tough this time of the year - easy to overheat the house.

    When starting up, you will see the stove getting real hot, but that doesn't mean the AB is ready to engage. Hard to go by stove top temp alone - when starting up, mine will easily go over 700F if I don't shut the air back a good bit, and I still won't have the sufficient coal bed.

    I also have a thermometer on the back/side like jdonna said (and thanks for that hint jdonna - it is a great help). I would watch the top - don't worry about going over 700F for a few minutes, it will drop quickly once the bypass is closed - but get a second thermometer for the burn chamber. That one will tell you if you are burning smoke.
  7. curber

    curber Feeling the Heat

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    My stove also prefers to be stuffed pretty full to keep the AB engaged and burning smoke-free. If I have a fire with just a split or two, even with a coal bed, the thing will crap out sometimes. That makes it tough this time of the year - easy to overheat the house.


    Mine also likes to be full of wood insted of one or two splits at a time. Pat
  8. curber

    curber Feeling the Heat

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    Mine also likes to be full of wood insted of one or two splits at a time. Pat

    Thats how I meant to say it..
  9. stoveguy2esw

    stoveguy2esw Minister of Fire

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    the few "downdraft" stoves ive seen runnig had a quirk i guess bt it was handy. when the secondary engaged they would quietly "rumble' you had to be right there listening to pick it up but this may save you constatntly going outside to see if its burning.

    other than that i dunno what to tell you as we do not do this type of stove so im not very well versed with it as many others in here are. hope it helps ya though
  10. Skeezix_McGoo

    Skeezix_McGoo New Member

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    Touchdown!
    I'm in the endzone.
    Last night, after listening to all of your advice, I broke down the EnviBlocks in the stove, cranked her on high until I had a bed of nice orange and yellow coals. Threw some wood in and waited about 5 minutes. Then I closed the bypass and presto! Chrystal clear exhaust. Not a bit of smoke- cleaner than Montana Sky!
    I then woke up this morning to a house that was 74 degrees and still a nice hot bed of coals. I opened the bypass and again, let her rip for about ten minutes. Closed the bypass and we are again off to the races. No smoke anywhere. Called my wife in to see it and showed my in-laws (who spent the night- hooray!) the clean emmissions. I've got it! One other thing I learned is that when I have the damper open and I want to close the bypass, it is important with this stove to have the air-flow lever all the way open as well. Then, after bypassing the damper, wait a little bit and then move the airflow lever down to about 1/2 or 1/4. I'm guessing that the afterburner needs that air to ignite- (any thoughts?)
    I wanted to than everyone here for your help. Love the stove and love this site! Good job to all. Now, I have a stove to go sit in front of and staer at all day. Thanks again!
  11. Troutchaser

    Troutchaser New Member

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    Good to hear Skeezix. I too am a downdrafter (crossdrafter), and these stoves can be frustrating at times. The common theme here is a deep coal bed. This time of year my living room/cathedral will be 80* just in building a coal bed from a cold stove. But hey, I didn't buy this stove to keep the house cool now did I?
    And I might add that dense hardwoods make the longest lasting coals: Oak, Hickory, Locust, Hard Maple. Ash and Cherry to a lesser extent. Low BTU splits just don't last long in the coal stage.
    I'm surprised the Blocks worked for you.
  12. Troutchaser

    Troutchaser New Member

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    And I might add that you've not seen a pipe smoke till' you've seen a downdraft stove that isn't re-burning smoke.
    You can probably gunk up a pipe pretty quick that way.

    Does the Oakwood have the ability to "throttle" the bypass?
  13. johnnycomelately

    johnnycomelately Member

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    gunk?
  14. Skeezix_McGoo

    Skeezix_McGoo New Member

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    Its all come down to the coals. I am sitting here watching my 500 degree perfect fire. Shhhhh :)
  15. branchburner

    branchburner Minister of Fire

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    Right, it needs a few minutes to get cranking. Usually I don't have mine full open - I go from 3/4 to 1/2 to 1/4 open in intervals.
  16. jdonna

    jdonna Member

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    Glad you have it working. The after burner does need a surge of air to get it to light off. Unlike a cat., down drafting needs higher temps to ignite smoke. Strongly suggest you get a mag. thermometer on the fire dome, helps out when you do run into a light off problem and some piece of mind.
  17. Treacherous

    Treacherous Minister of Fire

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  18. Troutchaser

    Troutchaser New Member

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    "Gunk"= Midwest Country Boy Slang for Clog.
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