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Needing help solving severe creosote problems with my Seton Wood Boiler

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by SLEDX509, Jan 6, 2012.

  1. tigermaple

    tigermaple Member

    Joined:
    Jan 3, 2008
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    Loc:
    Fingerlakes, NY
    I installed my GW in 3/07 and the first year was hell because I believed all the misinformation from the company and wasted some serious coin. Lucky I found my way here. First off, I have never taken my GW apart and cleaned the back hex ever (but I did have an overheat a couple years back that cleaned her up nice) I have no mixing valve or plate exchanger. No gaskets, but I did seal leaks. I have a seldom used draft inducer and 16' of chimney, no cap. The primary loop is 350'. The water temp in almost never at 180 in the morn, more likely 125º, but aways has enough coals to refire. The large house is 72ºI have no storage. But I do in a sense, and I believe this is the key to GW's and most wood burning boilers, old fashion cast iron radiators. I started replacing baseboard with cast iron in 2008 and what a difference. Now I have 18 of various sizes and couldn't be happier. My storage is in cast iron plus the water inside. They heat until the water is below a 100º and it seem the more the better. Only problem is price. In 2008 I was getting beautiful ornate 10 fin rads for 25 bucks, now the price is closer to 250 and they are harder to find. Plain ones are costing more also. There was a thread here a while back and someone was debated buying some rads cheap, well I would have bought em all if I lived nearby. As far as I am concerned cast iron rads are must have equipment.

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  2. 2.beans

    2.beans Minister of Fire

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    Mar 22, 2008
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    Loc:
    new hampshire
    im no plumber but if you have a 011 on one side i would think you should have the same on the other side? or have equal flow on each side of the heat exchanger/flat plate. what size pex between the boiler and house? move the water thru the boiler faster and it wont heat up as fast which would keep the boiler running longer. less idle time. i think you still need more draft.
  3. SteveJ

    SteveJ Member

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    Nov 19, 2007
    Messages:
    213
    Loc:
    CO 9000ft
    Kevin,

    I am running three aquastats

    1. One to turn the boiler pump on set at 160F with a 5F differential - my boiler protection does not allow flow to the load until about 160F - Termovar AF-4400A3

    2. One to control the draft door motor close at 185F with a 20F differential

    3. One to dump to my largest zone set at 195F with a 7F differential

    You are correct about matching the burns to the loads - trial and error to minimize idling until you have storage.

    Steve
  4. PassionForFire&Water

    PassionForFire&Water Minister of Fire

    Joined:
    Jan 14, 2011
    Messages:
    580
    Loc:
    Billerica, MA
    I have never seen a GW from close by, but by doing some Googeling yesterday evening it's my humble opinion that this wood boiler has no secondary burn above the fire before the flue gasses hit the HX.
    No air = No combustion.
    Looking at some pictures and noticing that there is no water jacket it seems doable to integrate some secondary air tubes above the fire; just like most of the EPA wood stoves.
    This will drastically improve the level of combustion and decrease the creosote formation.
    The work involved to put this in is probably equal to the work to clean a clogged-up HX with creosote
    I dare to bet that there are probably some Boiler Room guys that did this.
  5. tigermaple

    tigermaple Member

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    Loc:
    Fingerlakes, NY
    "Looking at some pictures and noticing that there is no water jacket it seems doable to integrate some secondary air tubes above the fire; just like most of the EPA wood stoves."
    It took me two years of operating this beast to come up with that idea and you look at some picts grasp it right away, damn.
    When I have to rebuild my GW this is what I would do. Integrating burn tubes between the hex tubes to force air at the creosote, especially in the back. The airflow could be controlled with a simple damper valve. The air would need to be preheated and only flow with the main damper open. I never talked with Fred about this idea, I wonder if he tried it. I don't see a down side if done properly, but ya never know until ya do it.
  6. Pat53

    Pat53 Minister of Fire

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    UP Mich
    Tiger, I can assure you that Fred NEVER tried it and would tell you that its not needed. he thinks the Setons burn super-clean now. Just let them idle all day and they stay nice and clean according to Fred ...LOL

    I would love to see someone come up with a secondary burn for these units. How hot do you think the secondary air would need to be to work effectively?

    Pat
  7. SLEDX509

    SLEDX509 New Member

    Joined:
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    Washington State
    Hey guys, I have not looked at other boiler designs too much, But I have started doing some research.. I am assuming that this "Secondary Air" is typical on most "gassifiers"? Would this be comparable to "Overfire Air" on a normal industrial boiler? It's almost embarassing to say, but I work as Control's Engineer at a power utility that burns Biomass in a boiler, and we use overfire air to control our Carbon Monoxide and Excess O2 readings on the backend of our boiler.

    Regards,

    Kevin
  8. PassionForFire&Water

    PassionForFire&Water Minister of Fire

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    580
    Loc:
    Billerica, MA
    It's certainly comparable, just on a smaller scale.
    If you have primary combustion air coming in from below (under-fire) or from the side, then all your oxygen is consumed at the bottom of the fire or somewhere a little higher up.
    If there is no over-fire air, typically called secondary air, you have an incomplete combustion with excessive creosote formation when the flue gasses hit the "cold" HX
  9. JrCRXHF

    JrCRXHF Burning Hunk

    Joined:
    Apr 28, 2008
    Messages:
    210
    Loc:
    Mid, Michigan
    I only have a few weeks running my Harman SF-260 that i got used. when i got it there was 3/4 to 1" of creosote in the back of the exhaust area and you could not see any daylight between the boiler tubes and the fire box on the top side. I cleaned about 1.5-2 gallons of creosote out of the boiler and did not get it all.

    Things i did to cut down on the creosote are:

    1. Only try and burn it hard 500F exhaust temp.
    2. Wrap the flue from the back of the boiler all the way to the top to keep it as hot as possible
    3. Mine does draft control from the bottom but i closed off the idle air and opened the door vents to let it idle when need be.
    4. Dry wood and i spray creosote cleaner once or twice a week.
    5. I run 1.25" lines to a 75 plate heat ex. return temps are around 5 delta T of supply always over 140. This seems to keep the walls black but not shinny.
    6. I turn off the heat once every 3 days or turn it down really low on the gas boiler when i go to work so when i get home i can burn a really hot fire.
    7. Keep the wood at the front so it has max time to heat as it runs to the back.

    I am still playing around with the boiler getting it dialed in but a fluke IR works great to help you check the temps of the boiler.

    I wish i had a gasifier but the price was really cheap on this one and i have no room for storage so this is why i have a old school boiler.
  10. ISeeDeadBTUs

    ISeeDeadBTUs Guest


    Ahhh! Now see? I'm gonna sound like an ass now -without even trying - but . . . I been dying to ask both SetonClone users AND EuroStyleDownDrafters where and how the secondary air comes in and when? 'Cause I also have been thinking there in NONE on my GW.

    Just thinking out loud here, but . . .

    If we ran refractory across the top of the primary combustion chamber (similar to the "new and improved" GreenWood) thus forcing the smoke stream to travel the entire length of the tubes, andmade a bypass at the back of the primary combustion chamber, we could isolate the tubes from the smoke. I'm postulating that creosote would not form on the tubes since they wouldn't be subject to idling.
  11. bigburner

    bigburner Feeling the Heat

    Joined:
    Aug 28, 2010
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    438
    sledx509 - What kind of numbers you guys look for %CO2, %O2 & PPM CO Hey we like controls guys, will fit in here.
  12. SLEDX509

    SLEDX509 New Member

    Joined:
    Feb 17, 2011
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    Loc:
    Washington State
    We run anywhere from 2% to 3% excess O2 and anywhere between 150ppm to 200ppm CO. We don't measure CO2 or NOX..... On my boiler at home I have an Allen Bradley PLC reading my thermostats, dump zone high temp switch from my wood boiler and running my Zone Valves, circulator, and electric boiler.. I hope to put some temperature transmitters on my outlet and return lines in the near future, that way I can trend the temps and potentially incorporate them into my PLC program.


    Regards,

    Kevin
  13. SLEDX509

    SLEDX509 New Member

    Joined:
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    Loc:
    Washington State
    Hey guys, I ended up cleaning out my chimney really good last weekend and It has pretty much eliminated my puffing back out the door when I first build a fire. Also I get way less smoke coming back at me when I load the fire. The odd thing to me, is that it's not like the chimney was restricted down to like 2" or 3" diameter opening, it was more like it had a 1/4" to 3/16" hard layer all over the entire surface area of the chimney all the way up. I would not have thought, it would have made that drastic of an impact on the draft.

    One more concerning thing, after I had my boiler running for several hours last night with my normal zones running, the boiler was on the verge of overheating. With the normal 2 dump zones running, my water temp was probably around 212degF to 215degF, and It seems as though it would have kept climbing had I not turned on one of my zones in the concrete of the basement. There is no doubt that the two dump zones were taking as much heat as they could because the outlet and return water temps on those zones were much higher than normal. I have built 2 fires since I cleaned the chimney and that is the first time I had experienced that in several years. Is it possible that I am still having too much combustion air coming into the boiler even when the damper is shut? If that is the case, is it going to be worse when I go to an 8" chimney?

    Regards,

    Kevin
  14. mole

    mole Member

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    159
    Loc:
    Western NY
    Good to hear you got the puffing fixed. if your temp is climbing like that while you're idling, then you've prolly got an air leak. It'll be the draft door cover, the firebox door, or the ash pan. I had that problem when I first installed mime. Turned out that I warped the ash pan. Some high temp silicone caulking fixed it. There's some old strings and pictures of peoples' custom gasketing jobs to fix this sort of problem. You just have to do some digging. Anthony D comes to mind.
  15. SLEDX509

    SLEDX509 New Member

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    16
    Loc:
    Washington State
    Mole... Thanks for the feedback. I had seen some of those older posts about making gaskets for the damper door, and it seems that most people used a bead of high temp silicone to make a gasket. I was at the Ranch&Home; store the other day and they had some of the that "White Weaved" fabric that they usually put around the inside of wood stove doors, I think it might be made out of NOMOX.... not sure. I was thinking about lining my damper door with that, and possibly my boiler front door. Fred Seton had me fill my ash pit door with SAND before I ever even fired my boiler up, so my ash pit has never been used. I feel the sand gives me a good air break... so to speak.

    Oddly enough, my boiler ran all night last night with only two dump zones on and did not seem to overheat. I am not sure what's going on..... I am going to have to a bit more experimenting.

    Regards,

    Kevin
  16. mole

    mole Member

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    I didn't read the part in the instructions about filling the the ash pit with sand until AFTER my first fire! Not too bright. I don't use my ash drawer either I made an ash scoop out of a short piece of 6"dia stove pipe. Scoops fast and easy.
  17. SLEDX509

    SLEDX509 New Member

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    Washington State
    In past years I was constantly cleaning ash out of the bottom, but this year all my firewood was seasoned very very well and for the most part extremely clean i.e.... No dirt from skidding. And I have had little to no ashes left after the fire burns out. I have not had to clean ashes once this year yet... The creosote I am not so lucky with. I have had to clean my chimney and boiler 2 times so far since November.
  18. 2.beans

    2.beans Minister of Fire

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    new hampshire
    i sealed all the above mentioned leaks. search me out i probably posted pictures of how i did it. anthony sealed his i believe, he also had pictures if you needed some ideas. ive got mine pretty air tight now. no more creeping temps hitting the dump zone.
  19. SteveJ

    SteveJ Member

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    2.beans,

    Are you still using the automatic draft damp in the stove pipe to shut off draft when the intake flap closes?
  20. 2.beans

    2.beans Minister of Fire

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    i haven't in a little while. i started to try to make the damper in the stove pipe automatically adjust exhaust temps as the boiler is running so it got unhooked. then new more important projects came up. so its on the to do list. it worked great, it would get the exhaust temps under 175* at idle, but you have to seal the whole boiler up or it can smoke out the feed door or anywhere else it leaks.
  21. Jesse-M

    Jesse-M Member

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    I found this to be true for me as well....
  22. bigburner

    bigburner Feeling the Heat

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    Aug 28, 2010
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    I have been looking at shaft mounted VAV damper motors with pressure ports, I get to much gravity, loss when in no fan mood, but would like it [damper] to float based on draft and/or air in. My vent connector is 24" in diameter so a bunch of heat escaping there.
  23. SLEDX509

    SLEDX509 New Member

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    Washington State
    Does having these "automatic dampers" on your exhaust pipes cause more creosote problems for you, if and when they are shut? Trying to get up to speed, it's my understanding that you want to get your entire system designed such that your firing hard and your inlet damper is open most if not all the time? Effectively minimizing the "Idle Time", that causes the smoke/creosote problems.


    Regards,

    Kevin
  24. bigburner

    bigburner Feeling the Heat

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    Creosote - I am trying to keep heat, when fire low. I have no creosote build up, it all burns in the fire box before the fire tubes, I get fly ash in the tubes. under certain conditions I get some condensation in the chimney vent connector, that's because I rob too much heat from the flue gas.
  25. 2.beans

    2.beans Minister of Fire

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    that is correct especially with storage. my goal with the damper in the exhaust was to calm the fire down quickly so the boiler wouldn't creep and hit the dump zone say if the storage was to temp or if you didn't have storage at all. i don't always run mine wide open until the wood is all gone. with my work sometimes its nice when you get home late and the boiler has enough wood in it to get a fire going buy just throwing more wood at it. the storage gives it the long hard run to clean it out regardless of my idle time.

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