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Flue Temps on EKOs

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by rreihart, Dec 12, 2007.

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  1. rreihart

    rreihart New Member

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    What temps do you see out coming out of your boilers? I don't have a gauge on my stove pipe, but I checked with an IR thermometer and it never read over about 240 F. As it entered the flue pipe, just a few feet away, it read about 200. I also checked the supply pipe coming out of the boiler and the thermometer read the same as the mounted gauge so it seemed to be accurate.

    I was suprised to see these temps so low. Shouldn't they be higher? Are these temps inviting creosote?

    Thanks.

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  2. Nofossil

    Nofossil Moderator Emeritus

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    I only have one of those cheap magnetic stovepipe thermometers at this point, but I won't see above 300 ever, and 250 is more common. No trace of creosote after 2 full seasons - just fly ash.
  3. Eric Johnson

    Eric Johnson Mod Emeritus

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    Outside of the primary combustion chamber, you won't see any creosote.

    Low stack temp with gasifiers is a good thing. Not like older stoves where you depended on the heat to get the creosote out of your chimney and safely onto your neighbor's car. Since all the creosote burns off in the gasification chamber, there's nothing to stick to your chimney. But it's all about heat transfer. Think about it this way: If the temps in your gasification chamber are around 2,000 degrees and the gas temp where the hx tubes meet the chimney outlet is 200 degrees, that means you've successfully transferred 1,800 degrees into the boiler water. Pretty darn impressive.

    I seem to recall slowzuki pointing out that if your stack temps get too low (below 180 I think he said), you run the risk of condensation in the chimney, which isn't good. But I don't think that's likely to happen with modern gasifiers. I know that nofossil is trying, however.
  4. Nofossil

    Nofossil Moderator Emeritus

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    Very trying, according to some.

    My brother does condense the moisture out of his exhaust, and has to collect and drain it. His chimney flue gas temps are around 120.
  5. termite

    termite New Member

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    rreihart,
    I haven't fired mine yet. Should be ready this weekend. Any advice for a fellow Biomax owner?
  6. rreihart

    rreihart New Member

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    I'm sure the EKO users can give better advice, but I have been burning for over 9 days now. The oil hasn't kicked on at all. So far I'm very pleased. I still don't have any storage so I've been keeping the fire burning. I basically load twice a day, before work and before bed, and I'll toss in a few pieces after work. When I load at 6 AM, I still have plenty of fire when I get home about 5 PM so I'm pretty happy with the burn time.

    A couple minor problems are:

    During loading, I do get more smoke in the basement than I'd like to see so I want to try to do something about that. Anyone else see that, or have a solution?

    The chimney bypass flap often sticks and doesn't always open when the door opens causing more smoke. I think this is due to creosote in the firebox. Maybe less idle time would help this.

    Overall I'm very pleased. We keep the house warmer than before and I'm not buying oil.

    Let us know how you're making out termite.
  7. leaddog

    leaddog Minister of Fire

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    On my eko80 I am running up to 450 on full blast. I just put in a thermometer with this thread and I'm cutting back on the primary air and trying to keep it down to 350-400. I am running my fans only about 1/2in to 3/4 in open. I'm hoping that I will save some of that heat that is going up the stack. The book says 400 on the eko all models but the book isn't aways right in the translation as we have all found out.
    Still learning and playing but this place is a great place to share and learn. I hope I learn every thing there is to know soon as I want to next learn all about solar heating as that is my next project. Well maybe then I better take some more of those vitamins. Maybe LOTS more.
    leaddog
  8. Grover59

    Grover59 Member

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    Now that I have a themometer that reads the actual gas temp in the flue pipe I am seeing about 320 to 350 full load, it is very consistant if the thing is all heated up it will stay just a little below 350 all the time. Last year I use to spill smoke into the cellar when I loaded it, I installed a small exhaust fan with some flex pipe that vented out of one of my cellar windows. this fan runs whenever the blower on the boiler is running. No that I am more use to the boiler I try and make it a habit not to open that top door until I really need to add wood, when I do this I never see smoke.

    Steve
  9. Eric Johnson

    Eric Johnson Mod Emeritus

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    If it's like mine, Rob, that bypasss damper sticking problem will go away after a month or two. I addressed the problem by changing my handle configuration so that I can open the firebox door while the damper is closed (something the regular setting is designed to make impossible), and then you can push the damper open from inside with a stick or poker. That's no longer an issue, since it doesn't stick anymore. I see the BioMax has a different handle design, so maybe you don't need to modify anything. But as the metal cures, or whatever, the problem disappears.
  10. Eric Johnson

    Eric Johnson Mod Emeritus

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    The bigger boilers must have higher stack temps, 'dog, because mine are in the same range as yours. I haven't really fooled around with the air adjustments yet, but like you, I'll try to get them as low as possible. I've got an old Condor internal stack temp thermometer which is probably way out of calibration. Unfortunately, the printed calibration plate on that unit can move independently of the needle, so it's probably all out of whack. Plus, the Condor goes up to 2,500 degrees, so it's really the wrong instrument for this application.
  11. termite

    termite New Member

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    rreihart,
    Try putting a spring behind the adjustment bolt for the flapper actuating rod (upper left hand side of upper door). Mine had a similar problem and Zenon suggested this. I haven't fired mine but the flap work better with the spring. I should have mine fired up this weekend. I have the big tank holding 32psi for three days now so I'm ready to plumb it in. Glad to hear about the burn time and your satisfaction.
  12. rreihart

    rreihart New Member

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    I look forward to the sticking bypass going away. Maybe I need to let it burn out and clean it off. I have a second fan in the back of the boiler that is called a draft blower. However it only runs when the main blower is on. I think if this fan ran during loading it would pull smoke through the bypass. I think I'll run that past Zenon and see what he has to say.

    Termite, my flapper rod already had a spring. Maybe I got mine after you discovered this issue.

    Maine, I have a basement window close by that I plan on putting a blower/vent in.
  13. Eric Johnson

    Eric Johnson Mod Emeritus

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    I don't think it's a question of cooking it out, Rob. I think it's more a passage of time issue. Kind of like an engine breaking in. Like I said, mine went away after about 2 months of steady use. I assume it has something to do with the metal chemistry.
  14. Grover59

    Grover59 Member

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    I found this worked very well and I still have not made a hood over the door, will do that before this season is out.

    Steve
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