1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

Air control setting no effect past about 25%

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by ratkillingdog, Dec 21, 2009.

Thread Status:
Not open for further replies.
  1. ratkillingdog

    ratkillingdog New Member

    Joined:
    Oct 5, 2007
    Messages:
    18
    I have the stove in my signature and enjoy it. Flue length is about 16.5 feet with one 22 degree offset right off the stove and then straight up class A pipe inside an interior masonry chimney. The draft control is effective only about the first 1/4. Pulling it out further has no effect. I added 3' of stack to test and it made no difference. Cracking the door makes a big difference. I have no real complaints, but wouldn't mind a bit more draft for vaporizing coals, (with the door latched). The stove burns well as is, but I am curious to hear from others. As I say, the first 25% percent of the draft does everything it is supposed to. How about You?

    Helpful Sponsor Ads!





  2. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    46,010
    Loc:
    South Puget Sound, WA
    Possibly, this is negative pressure in the room. Is this a basement installation? Try opening a nearby window a couple inches to see if the fire picks up.

    Or could it be the wood is not quite fully seasoned?
  3. LLigetfa

    LLigetfa Minister of Fire

    Joined:
    Nov 9, 2008
    Messages:
    7,343
    Loc:
    NW Ontario
    I have a very different stove but my air control works best between closed and 25% on the graduated scale. Mind you, my graduated scale is in the wrong place as the 25% mark is actually 50% of the range of motion. I've examined the range of motion closely and it correlates with the actual butterfly valve position so full open does allow the max air.

    Ignoring the scale, The range of motion between closed and half open is where I see positive results. Beyond half open, while more air enters, the heat output actually drops off so opening it too much has a negative effect, something I've had difficulty getting my wife to accept. She treats it like the knobs on the gas cooktop.

    I believe that too much air takes the stove out of the sweet spot for efficient secondary combustion. That said, the doghouse zipper air is more directly involved in the rate of burn than the primary/secondary air control. On my stove the zipper air is drawn from the room unlike the primary/secondary air which is drawn from the OAK. A pressure deficit situation would adversely affect my zipper air.

    Keep in mind the airflow pattern within your stove and how opening the door will change the airflow. On most stoves the primary air comes from the airwash system. Some stoves like mine, don't have separate controls for primary and secondary air so the balance between the two might be a compromise which migh explain the non-linear result to increasing the amount of air. The air also has to be heated and more air doesn't allow enough time for heating.
  4. firefighterjake

    firefighterjake Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    14,859
    Loc:
    Unity/Bangor, Maine
    If you're only using the draft control at the 25% setting I would say you're missing out . . . I mean to say, like LL my stove runs best when the air control is shut all the way or just a bit more than all the way shut . . . that's when I get the fantastic secondary action and maximize the heat. However, I also use and need the air control to open all the way up . . . that's the setting I use when I'm getting a fire started, when I'm burning down the coals when necessary and oftentimes when I do a reload on some small coals (typically in the morning.) And I often adjust the air control to the halfway mark when I'm working my way towards shutting down the air . . .

    I am curious . . . you say there is no difference with regards to the air control . . . and that the stove appears to be working fine . . . but I'm wondering if that truly is the case. What I'm trying to say is that 16 feet isn't all that tall (although you did say you added another 3 feet with no change) and I'm wondering if your draft is not as good as you may think it is . . . I would suspect you should be seeing a change in how the fire behaves when you move the air control lever from all the way open to all the way shut . . . in one case you should be seeing lots of flames coming off the wood and a relatively high flue temp . . . and with the air control the other way you should be seeing secondary combustion (i.e. Northern Lights, propane gas, etc.) and the temps in the firebox should be relatively high.
  5. ratkillingdog

    ratkillingdog New Member

    Joined:
    Oct 5, 2007
    Messages:
    18
    Yes, the stove is working properly. Grand kids and dogs give it a wide berth when the secondaries kick in. I was off in my 25% guess. Total range of motion is 4.5". The first 2" does it all and I too burn nearly closed for the best performance after light off. The wood is dry pine and the house has air leaks that I am working on. Closed to 2" does it all and after 2" there is no visible difference or difference in measured temps in the stove. The stack will cool by a few degrees though, indicating a slightly higher air flow. I wonder if the long "pull" would have more effect if my draft or chimney draw was less?
  6. sandie

    sandie Feeling the Heat

    Joined:
    Oct 29, 2009
    Messages:
    269
    Loc:
    West of Boston, MA
    "if the firebox is hot enough in one case you should be seeing lots of flames coming off the wood and a relatively high flue temp . . . and with the air control the other way you should be seeing secondary combustion (i.e. Northern Lights, propane gas, etc.) and the temps in the firebox should be relatively high. "

    I think you just said the same thing twice?
  7. SlyFerret

    SlyFerret Minister of Fire

    Joined:
    Feb 12, 2007
    Messages:
    1,434
    Loc:
    Delaware, Ohio
    Yeah, the first little bit of motion in the air control doesn't do anything my 30 as well. I run with the spring tip even with the front edge of the ash lip. Another quarter to half inch of motion (inward) gets me to the minimum air setting. After that, the rest of the motion makes no difference.

    I saw a picture once of the air control mechanism inside the stove. The way it's designed, this makes sense.

    Mike might be able to offer more technical information.

    -SF
  8. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    27,292
    Loc:
    Northern Virginia
    Since the draft can pull air from the zipper, airwash and secondary inlet until you close the primary enough to effect the balance between the three you will not notice much. Of course any of the movements have to be in stages to let the balance of the intakes and the fire itself adjust to the change. With a stove like mine that no longer has the zipper intake the adjustment of primary air is more linear.
  9. LLigetfa

    LLigetfa Minister of Fire

    Joined:
    Nov 9, 2008
    Messages:
    7,343
    Loc:
    NW Ontario
    Since I increased my zipper and made it adjustable, I use it as my first "go to" adjuster throughout the day. The zipper stays closed unless I need more heat or am burning down coals. All day long my OAK air is set to somewhere between 1/4 and 1/2. For overnight, the zipper gets closed and the OAK air is between closed and 1/4. Closed is a subjective term since both controls are notched and can never be fully closed. The OAK supplied air has a single control that shares primary, secondary, and airwash. It is so non-linear that less is more (more or less).
  10. ratkillingdog

    ratkillingdog New Member

    Joined:
    Oct 5, 2007
    Messages:
    18
    Mine is almost opposite of what you describe. From dead closed to 1/3 open do it all. Dead closed will NOT kill the fire, as it should be. I suspect more and more the wide "pull" compensates for various chimney draws.
  11. firefighterjake

    firefighterjake Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    14,859
    Loc:
    Unity/Bangor, Maine
    I think you may be right . . . what I meant to say was in one case the air control being all the way in or out (in my case it's all the way to the right) would result in lots of flames in the firebox and a relatively high flue temp . . . and with the air control the other way (all or most of the way to the left) would result in secondary combustion and the higher temps in the fire box. Thanks for the catch.
Thread Status:
Not open for further replies.

Share This Page