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My Everburn procedure

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by BurningIsLove, Nov 16, 2007.

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  1. chaynes68

    chaynes68 New Member

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    My setup is a mostly indoor 15 foot steel chimney straight up only 3 ft of it pokes up thru the roof (12ft class A and 3 ft of double wall pipe). I have a surface temp probe and a stack probe 18 inches up from the collar. How could I possibly get a more textbook installation for a stove...15ft straight pipe all inside!

    I doubt that I have an air leak...I have checked the seals real good. Some anecdotal evidence that I do not in an overdraft condition is that I have burned some pallet wood and can keep the stack temps under 800 degrees with the primary air fully closed and top damper open. If I opened the primary air full with pallet wood I'm sure it would get super hot. I did a warm the house up burn last week with 6 biobricks and the stack temps were lower than I was getting with pallet wood.

    Honestly I don't know very much about this...my conclusions could be wrong.

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  2. James04

    James04 Member

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    Sounds like overdraft would be ruled out. So what kind of wood was it and what were the settings? I would be interested in knowing how you make out with a load of bricks. I tried I think twelve and it was not enough to equal my usual overnight burn. If tonight is cold but not overly cold I may try 16.

    James
  3. webbie

    webbie Seasoned Moderator Staff Member

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    chay, your chimney is very similar to EPA test stacks, so it would seem fairly ideal. Just FYI.

    Just for fun, one of us should manufacture a couple dozen EPA test 4x4 and 2x4 (with spacers) and see how they burn. I'm not kidding. It would tell us something....
  4. tradergordo

    tradergordo Minister of Fire

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    What reason did you go with all double wall & class A for the 12 foot indoor section? Based on what you've said so far, it doesn't sound like you have a leak, but it does sound like you have excessive draft, which may be the result of this flue/chimney. Single wall pipe would put a lot more heat into your living space and reduce draft, I highly recommend that with an everburn stove mostly because the design puts so much heat straight up the stack (see my previous comments about heat exchange, or lack thereof with this design). I probably get as much heat from my flue as I do from the stove! By the way, I think 650 stove top might be too high as an indicator of when to damper down. When my flue probe reads 800, the stove top is usually 5-600, maybe a little hotter around the flue collar. I'm thinking excessive draft + most of the heat going right out your chimney would give the results you describe. Adding a damper like others here have done may help - but its not as good as replacing the flue with single wall pipe if you can (if its just a few feet though, it might not make much difference).

    And I'm still a bit perplexed about why excessive draft would cause the everburn stalling (this has been reported by multiple people, so I assume it's true). Anyone have theories? It has to be burning hot if the short burn times are true. Maybe so much combustion is happening in the main firebox that there isn't enough for secondary combustion? But then you wouldn't see much smoke out the stack...

  5. webbie

    webbie Seasoned Moderator Staff Member

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    Trader, the EPA setups I have seen have single pipe going up 15 feet...as long as it is interior, it should work fine for most setups. Straight up chimneys that are interior usually work very well - I have had Avalons draft great with 12 foot (total) straight ups.

    The over draft is just one theory - see my post about the three T's needed for combustion. Just like a candle goes out in the wind, too much air flow can "blow out" the gases too fast from the fire, they they are not burned. In the software world it would be the equiv of a script that didn't wait for one thing to be done, before trying to work on the result of that one!
  6. tradergordo

    tradergordo Minister of Fire

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    I might have been confused, I thought chaynes68 didn't have ANY single wall but I could be wrong. I have 8-9 feet of single wall coming straight up from my stove and I think it works well. I think if I had all double wall it might overdraft and I know for sure I wouldn't get as much heat into my living space.

  7. chaynes68

    chaynes68 New Member

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    my setup has no single wall pipe....
  8. James04

    James04 Member

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    Gordo,

    I think the overdraft could cause a stall or prolong the warm up time before secondary burn. This would be due to (at least on my stove). The fresh air being drawn through the refractory will cool it down below the needed temps for secondary burn. I got this idea because I noticed that there were black soot deposits just around the small holes in the refractory but all other parts were clean (hot). Once up to temp the rings disappeared. I hope I am explaining this rite. Does that make any sense?

    James
  9. tradergordo

    tradergordo Minister of Fire

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    That was my first thought, but then I was thinking "can too much air cause LESS combustion?" at first it seems crazy, because if, for example, you crack open the ash pan door you get a "blast furnace". But that is air fed directly to the firebox. It makes sense that excessive amounts of air fed directly to the secondary combustion chamber could actually cool things down and cause stalling.

    A very simple idea that people with excessive draft can try - just reduce the size of your secondary air intake. For temporary experimentation purposes, I bet you could just wrap tin foil over the flange and poke a hole though it (so you don't completely cut off secondary air).
  10. webbie

    webbie Seasoned Moderator Staff Member

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    Trader, you are right that there could be at least two distinct "too much air" scenarios.

    One is the "speed" of the smoke going past the holes - that was my guess.
    Yours is the amount of air needed to make the combustion happen.....

    Yours could be tested for in some way as you mention, mine could be tested only by slowing the flue from above - i.e damper in pipe, rock set into stove pipe (horizontal pipe).....obviously some of these are very temporary.

    One indication of an overdraft is that the stove would alway be extremely easy to light in updraft mode, and would not tend to smoke at all out the doors or top when loading.....of course, a perfect chimney would act that way too!
  11. tradergordo

    tradergordo Minister of Fire

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    If the primary and secondary air both come from the same single flange (bottom rear of the stove), and you covered it over, and the stove was airtight, shouldn't that have the same result as an inline damper in the flue? Both block the flow of air though the stove & flue.
  12. mikeathens

    mikeathens New Member

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    I think the damper in the flue allows MORE combustion air for primary and secondary, and sort of "dams" up the flow (I think it would provide for a positive pressure situation in the stove, too) - slowing flow from the inlet will choke off the amount of air available and cause a negative pressure situation in the stove (or maybe "less positive" pressure)?

    In my heritage, the flue demper seems to allow for more air for combustion, and less flow out the stack, sort of giving smke more residence time (and more air for combustion) in the stove
  13. swestall

    swestall Minister of Fire

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    ONE thing you may not be aware of: you do not have to hear the rumble to have the secondary burn functioning. I still have a hard time believing it, BUT, there are times everything seems to be OK but no rumble. So, I go outside and look at the stack, no smoke. Obviously everything is OK. Other times, no rumble = smoke and everything isn't OK. This thing needs a green lite on it...(LOL) Anyway, if you are not checking, then perhaps you might do that for a bit and see what's up. Another thing is that it takes the secondary mechanism a bit to actually start burning clean from the time you close the damper, not a great time, but some time. Hope that stuff helps you.
  14. tradergordo

    tradergordo Minister of Fire

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    I disagree, but maybe that's because I know how to listen for it. If my stove has secondary combustion, I can always hear it, I never said it was always loud though - you might have to stick your ear right up to the secondary air intake to hear it...
  15. dtabor

    dtabor New Member

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    Ive had the dancing northern light style "flame" and no sound whatsoever but I didnt check the chimney. I'll have to do that the next time and see.
  16. chaynes68

    chaynes68 New Member

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    Update for you all. Last night I burned only with biobricks in an effort to eliminate firewood from the equation.

    Started a fire with 4 biobricks (took a while) and repositioned them in a single row in front of the reburner. Once the stovetop reached 400 I added 2 more (6 bricks in a single layer on the floor of the firebox) and got the pile flaming pretty good then engaged everburn mode. I got the rumble, stack temps went up to about 500 stovetop was 425-450. Everburn stayed engaged for at least 45 minutes. While it was engaged I could hear a small amount of rumbling and smoke was clear and I was seeing "northern lights" etc. At the 1 hour mark everburn stalled when the bricks shrunk away from the reburner. The bricks in front still burned pretty well but it was not everburning since I was seeing a small amount of smoke out the chimney. All said I got 3 hours from six biobricks. Considering that I got 3 hours from a stove FULL of wood earlier in the week I would say that this is progress!

    Once I had a nice pile of biobrick coals I thought that I could keep everburn mode longer if I stacked all my bricks right in front of the reburner. So I loaded her up with 8 bricks and waited for temps to stabilize so I could get to bed. Welllll the stack temps got to 700 degrees in about 15 minutes and showed no signs of stopping. Everburn was really rumbling at this point! Since the stove was 100% closed up and it looked like stack temps were headed to 1000 I used my newly installed pipe damper to slow things down. With my damper 90% closed the stack temps reached about 800-820. As the pile began burning out the stack temp seemed to want to creep up again. Being tired (from messing with the stove all week) I needed to get to bed so I repositioned the bricks to the front of the stove to cool things down. I was not 100% comfortable with how stable the fire was, and I was not going to bed with it like that.

    It would seem that firewood is the most likely cause of my troubles. I am a little troubled with how hot my stack temps got during this little test (stove temps were 500 max BTW). Is this normal for this stove? I don't have enough experience with bios and everburn to know how hot is too hot....figure its better to be safe at this point.

    Progress is good...any suggestions?
  17. tradergordo

    tradergordo Minister of Fire

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    Congrats, you are well on your way to understanding the best ways to operate the stove. I would not worry about those temps you saw, they are normal (for very dry wood) and safe. I'd be worried if it stayed over 1000 for more than 15-20 minutes, but anything less than that is fine (I am talking about internal flue temps).

    As you discovered on your own - to get a long sustained everburn, you need to put some fuel where it is going to end up as coals in front of the throat opening. There are lots of ways to do this - pile it high, lean it against the back, etc.

    I've also been finding that if your coal bed is a little weak, sticking a piece of pallet wood right in front of the throat opening upon a reload seems to help. That piece of wood ignites fast and burns hot, and is quickly reduced to coals right where you want them as wood around it and above it ignites.

    Last night the house was already pretty warm, so I didn't want to fully load up before going to sleep. I had a good coal bed, I threw two small pieces of pallet wood on the coals, and just ONE single split (not even a huge one, but it was pretty big). The new thing for me, was that this split had been sitting at the edge of the hearth pad for a full week - it was "kiln dry" like I've never seen before. I knew it was dry, so immediately after I threw it in I dampered and cut the air off 100%. It started everburning immediately, and the stack temp went straight up to 900. The house was soon 80 degrees, had to shut the bedroom doors. I really didn't think an overnight burn would be possible with one split, but in the morning, 9 hours later, I had a very nice coal bed, the house was still 71 degrees (26 outside) and I was able to get the fire going again and everburning all within 20 minutes.

    So in conclusion - dry wood is critical for success with this stove in my opinion. If you have super dry wood it can be very easy to operate and I have been extremely pleased with the long burntimes I've been getting this year (thanks BurningIsLove for the tips). But good draft is still important (outside temps <30 and high pressure are a big help).
  18. swestall

    swestall Minister of Fire

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    Trader, I will concede to you that there is actually some "rumble" in the burner if you get close enough to hear it. What I meant to say is that you don't have to hear that loud blast furnace type rumble for the secondary combustion to be working. Thanks for the clarification.
    Over the past few months, I've learned to make it work; and you also seem to be getting it down. Others among us are also learning to make it work.
    BUT, I still think it is a lot of work and very time intensive. I am very jealous of those folks that have Quads, Hearthstones, Jotuls, and others that are far less labor intensive.
    Admittedly, I need a better draft and am compensating for that in my installation until I can get up on the roof to install a new liner in the clay flue. (Don't forget, the VC CAT stoves worked on this same flue for 20 years.)
    I applaud your effort to help people understand and work with what we have. It has bee of tremendous help to me and I see that it is to others.
    So, Thank You. - Steve.
  19. BurningIsLove

    BurningIsLove New Member

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    sorry,been away on biz the last week and havent been able to participate. Very happy to see others are getting better use out of their downdrafts.

    Has anyone tried the tin foil trick or other methods of reducing air intake during excessive draft conditions? While I wouldnt advocate that as a long term fix, it would be interesting to see the results and if that answers some of the open questions/theories.
  20. bobinmd

    bobinmd New Member

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    I've been lurking here for about a month trying to understand my new VC Defiant NC and have learned much from you all - thanks so much. While I'm still frustrated ~30-50% of the time with stalls and babysitting it, last night I was able to get a lasting secondary within 5 minutes of a completely cold start and the stove griddle temp at 100, so I wanted to share how I did it. My setup is a 6" flu that runs horizontal for 2' to a T, then into a flex liner with insulation packed around it in a clay tile lined chimney for about 15' with 2, 45 doglegs up the chimney, then into a triple wall metal chimney for 12'. So, 27-29' tall stack.

    I placed 1, 2" tall piece NS on each side of the combustion chamber entrance to create an elevated area right in front of the chamber and loaded several 1" pieces in the back to build a coal bed at the throat. I opened the ash pan for a few seconds to get it going initially, then closed the ash pan, but left the front doors ajar. It was going quite well so I figured, what the heck, and closed the bypass - liftoff. I kept the front doors unlatched but closed (I was babysitting it) and it continued to rumble along for 30 minutes consuming all of that smoke and gradually increasing in temp while I sat there amazed. I suspect it would have stalled had I latched the door and shut down the air flow, so I left it cracked. Then I added larger splits and the secondary continued - that is, until the load shifted a few minutes later and it stalled....However, I was able to burn all of that initial smoke from a cold start.

    My experiences are similar to everyone else - importance of good draft, hot coals in the throat, dry wood, etc. But the one thing that seems to be most important with my burns is the geometry of the air path to the combustion chamber. There has to be an easy path for the smoke to get to the back or I'm in for a long battle. I've had the stove at 600+ and no secondary (smoke puffing out chimney - very irritating) only to have the secondary take off when the load shifts slightly. I've also had stalls from a strong secondary when a log shifts. My stove typically hums along at 450-550 when in secondary and climbs to 600-700 after it stalls - I have a leaky door gasket. Also, it's rare for me to get more than 2-3 hours out of the secondary without pushing more coals into the throat, but I can get 8-10 hours of burn time out of a fully packed stove and leaving it alone after secondary is engaged.
  21. mikeathens

    mikeathens New Member

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    NOW...all you need is a rubber chicken, some incense, and a book on witchcraft. Too bad the ancient Mayan culture is gone. I'm sure with a few sacrifices and some fancy pyramid building to the right god, we'd all be in everburn heaven.
  22. tradergordo

    tradergordo Minister of Fire

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    Those temps definitely should not rise on a stall, get that gasket fixed. I think you are figuring this out already, but you kind of have to plan your fuel loading so that wood is going to coal over in front of the throat as I described before. And yes, cracking the ash door can do wonders for getting temps up and small stuff to coals in a hurry. You just have to be real careful about it, I think its a good idea to ONLY stick enough wood in there for your coal bed "starter" when you do the cracked door thing - that way its real hard to overfire. Once the starter coals are good, you can fill the firebox and damper down pretty quickly. This is the method I have been using for restarts in the morning, and in preparing the long overnight burns as well. It's been working great.


  23. webbie

    webbie Seasoned Moderator Staff Member

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    I was sorta thinking the same.....but, on the good side we have folks making (what seems to be) a bad situation just a little better. This particular thread may be one for the record books in terms of pages and time!
  24. swestall

    swestall Minister of Fire

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    I've been thinking about the front to back airflow thing since I started with this MONSTER. I think I am going to go out to the shop and take a piece of box metal stock, 1x3, and fashion an air channel that goes along the bottom front to back and feeds into the shoe area. I have noticed that when I can't get the secondary burning, If I make an air path on the side of the stove so there is flow from front to back (under or around splits), I can get and keep the secondary burn going, even when it won't go the minute before. I have an old stove in the shop that uses this type of channel to feed fresh air, perhaps the same thing will work going from the lower front center to the rear center shoe feed.

    But, Craig, the whole thing about black magic, the hokey pokey dance around the stove and so forth may also just be the trick. The point is we shouldn't need a trick.

    As far as overdrafting on these stoves is concerned, chime in Trader, I think if you have that condition you are just siphoning in so much air into the secondary chamber that you are getting a blast furnace effect that doesn't level out until the draft is sucking to its potential. And, the temp is going to normalize at whatever level the secondary burns at for that particular air siphon volume. So, it would seem logical that anyone with the problem of a runaway type secondary burns on these stovesd needs to reduce (or control) the siphon draft. A manual draft control would seem to be in order under those conditions. And, I'd say get one with the least amount of holes in it so you have real control over the situation.
  25. webbie

    webbie Seasoned Moderator Staff Member

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    I can fully understand the concept of these stoves (or any stove design) needing to be used hard - like for instance the original VC stoves (Vigi, Defiant) were somewhat the same - made for heavy use, and that is one reason why they were never as popular down south and out west. Too much stove!

    But these things seem to have a tough time with even being run hard......at least by our small sample. Does it seem that folks out west (any regulars who used softwood in their downdrafts) might have less fiddling to do?

    It is interesting that stove designs has went off into various directions. for instance, it could be said that the very basic type of PE setup - started with the Kent in 1984. Very similar. It works well, and usually needs no bypass, etc.

    Basic cat models have usually worked well also. I remember selling a lot of certain Russo models that had cats in them - very basic, more similar in setup to early (and present?) Dutchwest cast models with the cat right above the firebox. The only slight problem such designs has was "flame impingement", which meant that the cat might get shocked and crumble before it's time. But considering they were relatively cheap and under prorated warranties, it was not too bad.

    VC was known in the early days for "over-engineering" stuff, and it seems as if they still have that tendency. The result might be a better stove (in theory), but the jury is out as to whether it translates to the actual in-the-field experience. I guess they never wanted to fall into the "me too" trap of same-old stoves (as everyone else)....

    Anyway, I am glad to see folks getting the hang of them to whatever degree. And I am certain that they (VC and others) will take user experience into account on future changes to this design.
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