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Pellet Stove OAK inline booster fan for positive drafting?

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Don2222, May 3, 2013.

  1. Don2222

    Don2222 Minister of Fire

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    Hello

    The Eurostar and Osburn Combex combustion blower design got me thinking. Any pellet stove with an OAK could have a nice positive variable speed draft fan with a simple In-Line duct fan from home depot and a speed control.

    4" inline ductwork fan
    http://www.homedepot.com/p/Suncourt-Inductor-4-in-In-Line-Duct-Fan-DB204/100073963#.UYPcUL2CmcM

    Then a 4" to 3" metal duct reducer
    http://www.homedepot.com/p/Speedi-P...ece-Reducers-SM-RDP-43/202907205#.UYPfaL2CmcM

    Speed control
    http://www.homedepot.com/p/Suncourt-Variable-Speed-Controller-Hardwired-VS100/202803522#.UYPddL2CmcM

    With this fan, When the door is opened for ash scraping the flame would not change very much.
    Any comments?

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  2. Delta-T

    Delta-T Minister of Fire

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    yuo'd be neutralizing the negtive pressure of the system...basically defeating the saftey feature of the pressure switch. no good reason to do this.
    stoveguy2esw likes this.
  3. john193

    john193 Minister of Fire

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    Why would you do this?
    stoveguy2esw likes this.
  4. Don2222

    Don2222 Minister of Fire

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    Hello

    Air would still be passing thru, so the vacuum switch would still work. The Osburn Hybrid wood pellet stoves do this with their combex blower and even better the enerzone pellet stoves do this with a separate fan that looks like a computer fan mounted on the air inlet flange. Osburn states that this system is not spoiled by air leaks and provides better drafting.

    I know the difference is small but it would be a good experiment on a stove to see if there are performance enhancements. One benefit I hear is that opening the door does not change the flame much. I think the flame would also be more constant as the stove gets dirty. Therefore the stove would perform really good between cleanings and not slowly deteriorate.
  5. TheMightyMoe

    TheMightyMoe Minister of Fire

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  6. DexterDay

    DexterDay Guest

    Don is true in posting this. Enerzone and Osburn stoves use Two (2) blowers for combustion/exhaust.

    One is a small computer type fan before the burn pot (to pressurize) and the exhaust (like all other stoves) right at the end of stove to pull exhaust gases out.

    But SBI has a pressure switch in a special location, that is still designed to sense a pressure difference. As it still has a Vac switch.


    But I don't think it would be a good idea for all stove makes. As it wasn't designed into the stoves actual use. The Enerzone and Osburn units, have full adjustment over both motors and there output ( plus or minus 10%).


    image.jpg image.jpg image.jpg
  7. Don2222

    Don2222 Minister of Fire

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    Thanks Dexter

    Where is that vacuum switch hose barb located on your new stove?

    Interested to know.
  8. DexterDay

    DexterDay Guest

    Honestly. I would have to look? But because its almost neutral pressure? I would have to see how its plumbed in?

    Maybe its on the positive side of things? Or negative. Don't want to make assumptions, but I know it has a pressure switch (vac switch). So there is either positive or negative vacuum somewhere in the system.
  9. glenc0322

    glenc0322 Minister of Fire

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    What about the UL listing on your stove if you add the fan it could void the UL listing and if there is a problem or god forbid a fire. you could have a problem with insurance or a warranty. Just throwing it out there
  10. Don2222

    Don2222 Minister of Fire

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    If this proposed add on was away from the stove, it would not be a problem. It could be on the wall where the outside air comes in.
  11. Don2222

    Don2222 Minister of Fire

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    Hi Dexter

    Page 48 of your owner's manual. Looks like it is on the exhaust blower, same as alot of stoves. Neg Pressure for sure.

    Pressure tap (located on the exhaust blower) is blocked. Pull off the air hose from the
    exhaust blower pressure tap and the white (-) pressure switch tap. Use a thin wire to clear the
    pressure tap blockage and blow through the hose. If air flows freely, the hose is fine. If air does
    not flow through the hose, use a thin wire to clear the blockage.
  12. Lake Girl

    Lake Girl Minister of Fire

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    Dex, how many CFM on the intake fan on the Enerzone? The one Don is looking at is 65CFM up to 80CFM max.

    Don is there a damper on the intake air of that stove (manually or electronically controlled)? Have to wonder if that fan would mess up design system dynamics?
  13. DexterDay

    DexterDay Guest

    Not sure on the CFM. As for retrofitting a model that doesn't have one? I wouldn't do that...

    The Enerzone and Osburn line come with both from the factory (Enerzone Eurostar, Euromax, Osburn 500, Drolet Eco 65, Eco 45) with the Convex technology (2 blowers for combustion/ one before pot and one after).

    It works well. When I get home later, I will post a video of it burning and I will open the door. Very little change to flame because ofthe blower before the pot.

    Again, if it wwasn't designed from the Factory and UL Listed with it? Then I wouldn't just add it on. If something were to happen, your insurance would have a fit and likely not cover the claim.
  14. Don2222

    Don2222 Minister of Fire

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    Hello
    I know the exhaust blower on most stoves are 85 CFM so if the Osburn Hybrid is 85 CFM that would make the intake fan 85 CFM also since the combex blowers run in tandem. I suspect the Euromax system being a newer design they may have found from experience that 85 CFM is not needed for the intake and your Euromax intake blower is less than 85 CFM. So maybe the one I suggested up top set to 65 CFM would be about right. I may try this on my Harman because it looks like it may provide a more consistent flame at all heat settings! A lot of if's but would be fun to try.
    After talking to stove manufacturer's I found that changes to the stove body or shell would require the UL approval to be re-done. However control panel changes, blower changes and add-Ons do Not void the UL approval
  15. smwilliamson

    smwilliamson Minister of Fire

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  16. hoverfly

    hoverfly Minister of Fire

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    As the stove gets dirty the more restrictive it becomes and thus negative pressure increases. Right? OK so using a fan on the supply side might be "under" sized to help maintain normal air flow only after the system gets a bit dirty. Until then the combustion blower "over powers" that first fan. I think the key here is to maintain a normal negative pressure between the two fans, you don't want positive pressure push gases through the air wash system into the room. This is an experiment I would not do indoors until some knowledge of function has developed. My Mini air wash air supply comes form indoor air. A better option would be a solenoid operating the damper.
  17. MCPO

    MCPO Minister of Fire

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    The worse part of the stupid things people do is realizing these same people vote. (referring to the guy who lit his stove in the liv. rm. with no chimney.)

    Don seems to be a guy who has an inquisitive / inventive mind , not unlike many inventors who were often scoffed at for their experimenting. New ideas always require trial and errors and chances and can be dangerous . Unfortunately these days , rules , regulations and litigation can discourage serious tinkering .
    hoverfly and Don2222 like this.
  18. hoverfly

    hoverfly Minister of Fire

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    The worst thing is not asking questions in the first place before doing something.Thinking for a lot of people requires training, sad but true. Then there are others who are just naturalists in just asking constant questions to solve issues. We are actually a minority and some times we end up kill/hurting our selves as well, but then the way I see it that's taking a risk.
    smwilliamson likes this.

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