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OAK's On Englanders

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by dorkweed, Dec 9, 2012.

  1. dorkweed

    dorkweed Guest

    Why??? When you damp the primary air down the stoves draw from "internal" air sources not affiliated with the OAK/primary air inlet...........................................if my searches here are correct. Kinda defeates the purpose of an OAK once damped down..............................................hey?????

    Not arguing, just saying here.

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  2. SlyFerret

    SlyFerret Minister of Fire

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    The doghouse air comes from internal air through those two holes under the front of the stove. I thought everything else polled through the big tube in the back.

    -SF
  3. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Secondary is from room air also.
  4. imiller1974

    imiller1974 Member

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    The secondary burner intake on my NC13 insert is on the back/bottom. Which kinda sucks, because it draws air from the fireplace. The doghouse intake is the 2 holes below the ash-lip. In fact, because the blower isn't attached to the wood stove and just sits on the hearth, if you move the blower to either side a few inches, you can watch the fire blaze-up right in front of the doghouse. The controllable air intake seems to be the glass wash system, only.
  5. blel

    blel Feeling the Heat

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    So is dorkweed correct? When the stove is damped down, it is drawing from inside the house, not through the OAK?
  6. BurnIt13

    BurnIt13 Minister of Fire

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    Yes he is correct. Primary air only is drawn from outside air. Doghouse and Secondary air is drawn from room air, not the OAK. Does kinda suck.
  7. DaveGunter

    DaveGunter Member

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    I am running an 30nc and that is how I understand it also and am wondering the same thing about the OAK I have not hooked up yet, as primary air is almost completely shut most of the time. If I do hook up the OAK I will probably play with blocking the doghouse air inlets so I can control the primary air completely. Still thinking because after spending so much time air sealing my house, I am resistant to punch another hole in the house envelope.

    I am wondering how the burning characteristics of a nice long secondaries blazing burn will change if the primary air is coming mostly through the air wash as opposed to mostly through the doghouse. What I'm talking about here is that blow torch effect of the air coming through the doghouse as opposed to the bigger flames that the air wash air creates and whether that will change the secondary burn.
  8. Highbeam

    Highbeam Minister of Fire

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    This is a drawback of some stoves. Really a disappointing design decision. I like OAKs, the concept and the reasons, but with a stove designed such as this there is no point.

    My last two stoves were 100% fed air from the sealed OAK nipple. That's what you want. Otherwise it's like having big holes in the intake tube after the air filter on your truck.
  9. DaveGunter

    DaveGunter Member

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    Exactly, almost makes me think the OAK intake on the stove was added after as an afterthought, maybe so the stove will meet regs for mobile home installation etc...
  10. Highbeam

    Highbeam Minister of Fire

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    It's required in my county, and perhaps state, as well. My county includes Tacoma and is a huge county, both stove installations would have been rejected by the inspector if I hadn't installed the OAK. I asked them. I like lots of things about the engander brand, most everything really, except this feature.
  11. SlyFerret

    SlyFerret Minister of Fire

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    Out of curiosity, what sort of CFM does the 30 draw through the fixed doghouse and secondary intakes?

    I know that will vary based on the house and the stove/chimney system, but I'm just curious about a rough estimate, since theoretically, there should be a minimum viable amount required for the stove to operate properly.

    The stove probably isn't moving much air through those intakes compared to what it would draw through an OAK for primary air. I know I certainly don't shut my primary air down all the way. I wonder how much air I'm actually using trough the primary and the fixed openings when my stove is cruising.

    I don't have an OAK, so in my case it doesn't matter. I'm just thinking that there still has to be SOME benefit to it. I'm thinking it would be nice to have some actual data to discuss.

    Mike, are you reading this thread? Can any of your engineers comment?

    -SF
    dorkweed likes this.
  12. dorkweed

    dorkweed Guest


    x2
  13. DexterDay

    DexterDay Guest

    I agree 100%.. The primary may be "damped down" as posters noted above. But they must realize that an EPA stove does not completely shut down or close completely. There is still a gap. Look inside the back of the 3" intake and you will see what I am talking about.

    The doghouse and secondary air are internal air, but the CFM would be much less than Primary. Even damped down or shut.down.
  14. dorkweed

    dorkweed Guest


    Do you know this for a fact or are you taking a SWAG?? Reason I ask, is for the "blow torch" effect from the dog house when damped down. It's pulling some air through!!
  15. stoveguy2esw

    stoveguy2esw Minister of Fire

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    ok, primary air is drawn throught the OAK, secondary and tertiery air are pulled from house air. as for shutting down the primary completely non cats are designed where this cannot be fully closed so even with the draft control in the fully "closed" position there is still airflow through this air pathway, this is generally the rule on "non-cat" units.

    essentially the draft control effects the "ratio" air division between the 3 types of input

    looking at it this way; if "X" is the amount of air pulled out the flue collar of the stove and "A" is primary(airwash) "B" is secondary (air tubes) and "C" is tertiery (dog box) then X= A+B+C now with the draft control open A would have the lions share of the X air budget, as this draft control is closed the ratio between A versus B+C starts top shift , the primary is lessened which slows the burning of the "logs" while the secondary and tertiery are increased to create a stronger reburn process which is what allows the unit to burn "low and slow" and still heat like it does.

    as for why these air sources were set up the way they were i have no idea wasnt part of the design team. i do feel though that the quantity of air pulled through the non primary locations is not nearly as large as the air pulled through the primary even when the unit is backed down, though it is more than when the unit is not backed down
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  16. DaveGunter

    DaveGunter Member

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    Thanks so much, nice to hear it from the source. If I understand you correctly, the primary air is always more than the secondary/tertiary, therefore an OAK should make sense even if you burn considerably damped down most of the time?
  17. stoveguy2esw

    stoveguy2esw Minister of Fire

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    yeah thats pretty much correct. even closed all the way down on the draft control there is still a reasonable amount of primary air being supplied, so an oak would be a benefit
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  18. pen

    pen There are some who call me...mod. Staff Member

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    As to the design of having secondary and tertiary air drawn from the house instead of the oak, I wonder if the reasoning was they wanted the air entering the stove at these locations to be as warm as possible?

    Even though secondary air gets pre-heated as it moves to the tube, perhaps having ice cold outside air coming in here could change the characteristic of the burn depending on outside temps or cause damage even?

    pen
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  19. Machria

    Machria Minister of Fire

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    Also to add, don't forget many/most modern stoves draw some air above or below the window, making it a "Air Wash" system to keep the glass clean. So the moral of the story is, you will never get 100% of the air from the OAK, but you get MOST of it. Good enough for horseshoes!
  20. stoveguy2esw

    stoveguy2esw Minister of Fire

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    preheated secondary air is a big deal with this type of stove. if the combustion air for the secondaries is not preheated it makes a big difference in combustion efficiency. you may well have nailed it pen.
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  21. Highbeam

    Highbeam Minister of Fire

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    What? Don't you realize that the air being fed to the airwash does indeed come from the primary air system system? Did you think there was another hole in the door for the airwash? There isn't. So the moral of the story IS that many if not most stoves take 100% of air through the OAK.
  22. stoveguy2esw

    stoveguy2esw Minister of Fire

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    actually, many older versions of "airtight" stoves with glass in the door used the "missing gasket" airwash, though its not common at all now. most newer designs do use the primary combustion air as the "airwash" kind of a "dual purpose" design. i expect future regulations will eventually prohibit using "house air" for new designs may already be in place for new designs already. im not in the design business so im not certain one way or another.
  23. Highbeam

    Highbeam Minister of Fire

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    True, smoke dragons sometimes didn't even use door gaskets. I feel pretty confident that this thread is about modern stoves.
  24. SlyFerret

    SlyFerret Minister of Fire

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    Good pint, Highbeam! I just thought of that too. The primary can't be shut down too far, or the air wash won't work!
    -SF
  25. Machria

    Machria Minister of Fire

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    I'm under the impression based on some video's I've seen, some of the stoves have inlets around the top, or bottom, or sides of the glass for the "air wash system. No?

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