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anyone thought of this

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by ditchrider, Jan 16, 2013.

  1. ditchrider

    ditchrider Burning Hunk

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    So.. with so much advice about staging the air control down, as opposed to running the air steady or just getting the fire going and then shutting the air off...

    and, believe me, I understand that a slow shutdown is necessary in the operation of a non-cat epa stove.

    has anyone or any company thought of a timer based mechanism? Just a simple switch that, when the fire gets rolling really well the woodburner just sets the timer and over (for example) about 30 minutes the timer gradually shuts down the primary air?

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  2. StihlHead

    StihlHead Guest

    I have thought of that, using a spring loaded lever that you can ratchet open and it 'ticks' closed slowly.
  3. Dune

    Dune Minister of Fire

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    A timer would certainly be better than a runaway stove, but I often wonder about a temperature controlled air inlet damper.
  4. Blue Vomit

    Blue Vomit Minister of Fire

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    Sounds good but that would never work for me. Too many variables. How much of a coal bed am I loading on, what wood am I loading, how tight am I stacking it, what is the outside temp, etc.
    Some days my stove can take off and I can get it dialed in at about 20 min.
    Other days it may take me close to an hour, based on the variables above.
    Interesting idea though.
    Edit: I'm referencing the OP
  5. Prof

    Prof Burning Hunk

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    Quadrafire has something similar to this that controls the "start up air." I wasn't crazy about this idea, and really wouldn't trust something like this for the primary air. Like others have said--just too many variables.
    Huntindog1 likes this.
  6. Blazin

    Blazin Member

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    A house I once rented had a stove from Sears that had a temp controlled air inlet. A large coiled spring that would expand or contract connected to a rod on the inlet. Worked pretty well as I recall.
  7. MasterMech

    MasterMech Guest

    VC built stoves for years with thermostatic primary air feeds. Blaze King still does. In this day and age, I wonder if it could be controlled electronically, with flue temps, stovetop temps, and possibly a cad cell (flame sensor) for inputs?

    With a manual override for power outages of course.
  8. ArsenalDon

    ArsenalDon Minister of Fire

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    Ditto
  9. Village Idiot

    Village Idiot Burning Hunk

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    My Quadra-Fire 7100 has a time feature for the combustion air. They call it "automatic combustion control" (ACC). Sliding the air control lever to the right increases the air. Once you get about 3/4 of the way, there is resistance. Pushing further winds the mechanism and you can hear a ticking noise start. Then you move the lever back to the left to your desired desired final position. Over the next 45 min. or so, the air control slowly closes down. It works, but I almost never use it. I find that with well seasoned wood, I can damp down much sooner that the ACC would and therefore get longer burns. (Every little bit counts.)
    Blue2ndaries likes this.
  10. BobUrban

    BobUrban Minister of Fire

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    The spring coil works well on the old school VC stoves and would open/close with stove temp so for simplicity that is always an option. I am sure the same principle would be easily mod'd onto nearly any stove. My issue was/is my somewhat necessary paranoia with a fire in my house. I always found myself dbl checking the spring thingy. As with anything the more moving parts - the more chance of failure - with failure in this arena potentially meaning a house fire.

    I am guessing from a former liability insurance guy that there is huge liability potential for stove companies to say anything like "auto shut down/turn down" and even if the manual warned "not fool proof" failure of the device could be a huge payout. This in itself would limit the companies from pursuing such technology. Dealing with heat, ash, mess, coals, 1000's of different operators and so on a mirriad of potential issues abound.

    I believe there was a "smarter than I" person on hearth that developed a system with sensors in the stove and flu to do just this but it was a post purchase mod and I am sure eliminates any warrantee.

    The idea in principle is great but in practicality kind of scares me.

    So to answer the original question: "has anyone thought of this?" I am sure all stove companies have thought of and worked on such technology but the legal staff has put the hammer down on it. JMO

    Bob
  11. 69911e

    69911e Member

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    I designed and built one which would allow you to set the air to "start" and after a variable period of time allow the air to go to a variable "run" position. I implemented this using a UL listed pneumatic timer as these are more reliable than any electronic/mechanical system (and I design electronics). I did this in case I forgot to cut the air back and walked away.
    I don't use it as I now have dry wood and I now get the flames very fast with morning coals or reloads.
  12. northernontario

    northernontario Member

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  13. rkofler

    rkofler Burning Hunk

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    I would be more interested in something that would open the air as temps went down. I get the stove loaded and up to temp, shut down the air, now enable a device that slowly opens the air as temps lower. Would definitely help in the morning with the amount of coals. Guess it might also cool down the stove too much.
  14. northernontario

    northernontario Member

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    It's all in how you build the system... I haven't had time to do it yet, but that's the concept behind using a PID controller... closes and opens the damper. Same with the SmartStove system... it's not just about closing down the damper to prevent overfiring.
  15. oldspark

    oldspark Guest

    Just going by time wont work due to different conditions, been a couple of units out for a long time (before EPA stoves), I had one on my Nashua that used the temp from the stove to control the primary air, it worked but I quit using it because I was smarter than it was.
    Mother Earth News made one that used flue temps to control primary air which I thought made more sense, not sure it would work with today's stoves.
  16. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Quadrafire has had the startup air feature for a long time.
  17. WES999

    WES999 Minister of Fire

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    I have built an automatic air control. You need more than just a timer, mine has a probe in the flue and a digital timer( not shown in pic).
    The way it works is when the flue temp reaches 875::Fthe damper motor is actuated, for about 3 sec, this will close the air about 1/4.
    The timer waits for 20 sec, if the flue temp is still above 875::Fthe damper motor will be actuated again and close the air another 1/4.
    Cycle will continue until flue is below 875::F.

    The system works quite well, if you load on a hot coal bed you will get some overshoot, but the flue temp will usually be under 1000::F.
    I recently made a video of my system in action, when I get a chance I will post it. PDR_0005.JPG
    ditchrider and northernontario like this.
  18. Machria

    Machria Minister of Fire

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    Sounds like the BK temperature controlled tstat.

    Wess999, that is some serious shat!! _g
  19. Waulie

    Waulie Minister of Fire

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    I would like a simple one that will open my air control half way 2 hours before I get up. Couldn't be that hard to do could it?
  20. ditchrider

    ditchrider Burning Hunk

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    On the rear of my Aunt's Hearthstone II there was a mechanism that appeared to be a temperature affected air controlled valve. On the air intake pipe there was a bimetallic spring mounted on a (i believe it was a butterfly style) valve.

    So I knew attempts have been made. And the Blaze King feature is no secret. But it is a cat stove which deals with the creosote issue. My question is regarding the non-cat stoves in particular.

    There have been times after I've loaded my hot rock that I've gotten side tracked or was ready to get to bed.

    Good replies, though. Thanks guys!

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