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poor draft and smoke spillage with new jotul f100

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by dflone, Jan 12, 2006.

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  1. dflone

    dflone New Member

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    My recently installed jotul f100 (small) spills quite a bit of smoke when loading. The draft control also completely chokes the fire to death at anything below 1/3 open. The stove rear exits and runs 30" horizontal (1/4" rise /foot) with one 45 deg. before entering the metalbestos pipe that runs 21' vertical (4' above my peak). I've used airtights my whole life for primary heat so this is a real mystery. The Jotul dealer said I'm not burning the stove hot enough- that i have to get it to 650 degrees! I can only get it to 600 with the air all the way open, and besides, who ever heard of a stove that needed to burn at 650 so that it woudn't spill smoke when the door was opened? How do i heat the house when it's in the 30's or above outside without sweating everybody out?

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  2. elkimmeg

    elkimmeg Guest

    There are 2 types of chimney pipe one that is insulated with one inch air space, Cheaper, and one that is packed with insulation
    If your pipe is running outside the home and exposed, you could be drafting poorly, due to heat loss in that exposed pipe.
    The packed insulated pipe affords the better heat retention in the inside pipe and thus better draft. That's one possible explanation.

    The second one has to do with negative pressure in your home.. Is there a HVAC return near the stove or other combustiable appliances near by? What about a cloths dryer, bath vents, or kitchen stove vents removing air. If other fuel burning appliances are sharing the same space, like a cellar, then chances are you do not have enought makeup combustion air present to support what is needed for any to function properly. This wouls also explain the smoke when opening the door. If you are noy sure there is a formular to figure this out. For every 1000 btus input 50 cubic feet of free flowing air is required You have to find your cubic vollume of the area add up the all the appliances demand and divide do some math

    In a modern extremely tight constructed home it might be just that too tight. Meaning the normal air leaks of a less tight home, is not available to makeup the air lost in promoting the stove draft. You might have to crack a window to nutralize the pressure differencial and be a source of makeup air till the stove gets going.

    If that is what Jotul gave as and answer that is plain BS. The stove can opperate at 650 but it is hard to keep it opperating at that temp at all the time.

    The third factor is not draft related but due to the quality of the firewood. and it moisture content. If it is not dry enough, too much heat and energy is used drying it. This will create more smoke, less heat, poorer draft conditions, and more cresote build up in the chimney, which is dangerous. Cresote builds up in the chimney lines and reduces the passage area of the chimney which reduces draft. How clean is the Chimney?


    Finally after eliminating all of the above as possible causes: It could be particial blockage or the actual stove causing poor preformance. Things like the bafflet plate missed aligned the inlet air mechonism not opperating properly. Try this, get your fire going what ever size splits you are using split them in half. Add as many as needed to get it going and build a good bed of coals.

    If your wood is hissing or moisture is bubbling out the ends, then your wood is not dry eonugh. Try a package of supermarket bundle that has been kilmed dryed and see if that gets the desired results. You would not be the first person to buy seasoned wood to find out it is not all that seasoned. Running a stove takes time to get the routine down, there is a learning curb. If educated by non EPA stoves of the past, these modern stoves act quite different.
  3. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    We have an F100 that drafts better than Lyndon Johnson and sits next to a door which can be opened to eliminate the pressure issue. It is touchy about smoke spillage at loading also.

    The biggest factor is the stove design. Air enters from above the door, or the secondary burn holes, makes a trip around the firebox then across the baffle and then exits in front of the baffle a couple of inches behind the door. Therefore the smoke-path is aimed right at the door so if you do not crack the door and give it a good long time before wider opening the smoke is going to come out the top of the door. That is where it was headed and given a choice of turning up 90 degrees or proceeding straight ahead, well you know. Also, the secondary air holes in the top back are aimed directly at the door.

    I don't believe the stove would operate any differently if you got it up to a thousand degrees, physics being what it is. Just a quirk of the stove. They had to stuff a lot of function in a really tiny space.
  4. Rhone

    Rhone Minister of Fire

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    My unit pours smoke out the door when I reload like you wouldn't imagine. Here's my problems: Since my house is a ranch, with a low pitched roof, and a raised hearth my liner is pretty close to the minimum length that will work with my insert (I think it wants around 16 feet, in the end I probably have 18-20 feet of vertical liner). The longer, the better. Next, flex liner restricts air flow more than solid. I have flex connecting my insert to my solid liner (if it were flex all the way it would be worse than it is). Ovalizing your flex pipe to fit through your damper restricts air flow. Mine was ovalized. When they pulled my insert out they crimped the flex pipe at the block-off plate restricting air flow there, and lastly didn't trim off the top of my liner so it stuck way out the chimney. On a very breezy day the liner's rain cap acting like a parachute and grabbed the wind which twisted it just enough to break all the seals on the top of my chimney so I now have no seals up there. With the top seals broken, and the inside of my flue exposed to the outside elements my liner can't get as hot as if the top were completely sealed off to improve my draft. When I look on a cold day, I can see the little heat waves coming out the liner itself, AND out the top of my chimney where those seals are blown apart. At least my chimney is on the inside of my house.

    So, I have just a hair over the minimum height chimney, flex pipe, ovalized, crimped, with broken seals at the top of my chimney so my draft stinks! Come spring it's all coming out, the flex pipe is being replaced, I'm torching the damper area so it doesn't need be ovalized, trimming the top, putting cement around each joint in the liner, putting mineral wool around the liner at the top of my chimney and putting it above my metal block-off plate then sealing it properly to the top of my chimney so it doesn't blow sideways again and keep my seals up top intact. I can't wait until I can stop the smoke pouring out whenever I reload, there's a ridiculous amount.
  5. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Won't ever forget him. The sumbitch drafted me.
  6. dflone

    dflone New Member

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    Thanks for all the replies - it's great to hear constructive feedback compared to the dealers brushoff. My chimmney is outside, all 21'. Though it is metalbestos, insulated, and my friends have similar runs with great draft in their airtights. I'm burning hard maple seasoned two years in a covered woodshed(no walls). My house is small, 820 sq' but no other air demands from appliances. The walls are unsheathed, just roughcut siding and same paneling so leaks abound. We've also tried the windows open and no difference. The pipes are all clean. One thing I have noticed is that when I first light a fire and the stove is cold I get some smoke drifting up from the back of the unit. Seems to be coming from one of the bolt-heads on the back but I figured that such a small leak shouldn't make too much difference. My cousin with the smaller jotul has a twelve ' outside run and a mammoth draft. Also, when I go outside and light a piece of paper in the cleanout the draft roars and pulls the burnt paper ash right up the pipe. i have run a burning match along the top seal and there doesn't seem to be any leaking going on.
  7. dflone

    dflone New Member

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    [quote author="Frank Ivy" date="1137143658"]So the stove's passageways are definitely clear from the firebox to the pipe tie in? No chance that there is an air restriction?[/quot

    All clear. Last night I took it all apart for the second time in a week to double check and I have to sheepishly admit, to seal the connections from the stove to the metalbestos with stove cement. I'd never done this in the past with my other woodstoves but my other stoves were all large units with interior chimmneys. I'm using close-clearance duravent from the stove to the insulated pipe and the fit seemed to be pretty tight but I sealed anyway and I'll light a fire soon and see what happens. The metalbestos is only a metal to metal connection and I have to believe that there must be some leakage there so if it's an issue for the connector pipe why not the metalbestos? I'm a stonemason by trade and have built countless masonry chimmneys that performed beautiful whether inside or out and here I Installed a prefeb chimmney because of a time constraint. Like the shoemakers kids...
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