Wood Stove Thermometer

Discussion in 'Homesteading Questions' started by suitcase_sally, Dec 24, 2006.

  1. suitcase_sally

    suitcase_sally Well-Known Member Supporter

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    I was reading Missyinohio's thread about her problems with the chimney and someone was talking about a thermometer on the stack. I was at TSC today and bought a Rutland magnetic themometer. But to get it up to the "proper range", even just barely in it, it is about to fry me out of the house. Is there a way to check the calibration on this thing? I have an oven thermometer that sits on the top of the stove right where the stack starts and when it reads 200 deg., the new thermometer on the stack reads 275, and that ain't hot enough (but I'm gettin' purty warm!) Any advice?
     
  2. KindredSpirit

    KindredSpirit Well-Known Member

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    Maybe your wood stove is too large for the area you are heating. I used to run my stove at a temp of 400 to 450 degrees. I used a magnetic thermometer that I had on top of the stove. I cooked on there a number of times. That was my usual running temperature, but I was heating a fairly large room with a pretty small stove. They say not to buy the stove too large for the room, could that be the problem? I know you want a hotter fire to keep the amount of creosote down in the chimney.
     

  3. Beeman

    Beeman Well-Known Member

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    To check calibration put it in your oven with your oven thermometer and compare.
     
  4. scaryguyoy

    scaryguyoy Well-Known Member

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    Are you supposed to put it on the top of the stove or on the stovepipe?My thermometer goes on top of the stove.Perhaps there are different types.
    Scary
     
  5. Rockin'B

    Rockin'B Well-Known Member

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    I have a thermometer that I bought at the stove shop when we bought the stove. It is magnetic and I was told to stick it on the flue as low as possible. I can't put it on the top stove surface due to it being cast iron and the cast is a surround built around the fire box. It would read low all the time if placed right on the stove surface. It's on the flue just and inch or two up it.
     
  6. Country Lady

    Country Lady Well-Known Member Supporter

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    This is our first year with a fireplace insert and we're still in the learning curve. I've been reading about the thermometers and wondering if and how they would work with an insert.
     
  7. Rockin'B

    Rockin'B Well-Known Member

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    Most all inserts are welded plate steel so I'd stick the thermometer right on the top surface as far back as possible. From what I've read , and been told at a couple of stove shope, the optimal burn zone is 300 to 525 deg.

    525 will drive us out of the house though we do fire it up towards that temp once a day to help keep the flue clean of creosote.
     
  8. debra in ks

    debra in ks Well-Known Member

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    I'm the one who mentioned the thermometer. I have a Lehman's thermometer on my stack. I didn't see it on their website when I checked just now, but that doesn't mean they don't have them. I did find it in their 2003 catalog, here's what it says.

    Our thermometer warns you when creosote is forming. Eliminate creosote! Maintaining proper chimney temperatures is half the battle. Our magnetic thermometer sticks anywhere and gives accurate temps from "Sooty & Creosoting" range to "Overheating " range. Satin Black with easy-to-read gray lettering. 2 1/2"OcD,USA made.#H406-294 $15.95. Note:accurate readouts on single walled pipe only.

    Just went and measured and mine is exactly 24" from the stove. I seem to remember the directions saying put it at least 2' from the stove, but not more than 3'. There's a place to put a screw right in the center because eventually the magnet falls apart. (It says "use safety screw" on mine.) It's not perfectly accurate of course, but I've found it to be acceptable. I was learning how to run a woodstove in '99 and thought it seemed like a good idea while I got a good feel for my stove.

    Merry Christmas!
     
  9. stanb999

    stanb999 Well-Known Member

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    Is this a new stove? Like a new non-catalitic. If it is you don't need the thermometer. They only work when you have heat blasting up the flue (old ineffient stoves). The new stoves have lower exaust temps. Due to the baffolds at the top which increase the effiency buy slowing the loss of super heated air and directing it to the top of the combustion area. Because of this they will read at a max of about 350 (at least that is what mine does). If you try to fire them at 400-500 flue temp you will ruin the stove over a short time.

    To run this stove right if this is a new style stove just be sure to ALWAYS have flames present. Don't leave the fire so low that it can't flame and burn the smoke. Another easy way to tell is by the smoke outside. You should only see smoke when you first start the fire or when you add new wood; even with this it shouldn't smoke for more than 30 min. or so.
     
  10. suitcase_sally

    suitcase_sally Well-Known Member Supporter

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    No, it's not a new stove. I bought the house in '78 and it was in then. It's a Franklin-type and not air tight.

    This morning when I fired it, it got up to the proper range right away, so I'm thinking it just needed a trial run (?). I'm sure the humidity and barometric pressure may have something to do with it, too. It was fairly windy yesterday, but is calm today.

    The room is 12 x 18 and opens into another room 9 x 16 and a hallway that goes to the bedrooms.
     
  11. cast iron

    cast iron Well-Known Member

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    True. My "epa certified", "high efficiency", "non-catalytic", "secondary burn", "close tolerance", "blah blah" stoves manual says to run the fire box at about 600-800. The stove pipe temp runs 450 or so at the base ring on the stove and decreases gradually as it heads for the roof (using an IR thermometer). By the time the pipe enters the connection box for the outside chimney sections at the ceiling the pipe temp is down to about 200. Pretty hard to get high pipe temps on stoves like these with all the baffling in there, as you say.

    Sometimes the firebox will sneak up to 800, but I get nervous at that point as the pipe temps start to get up there a bit.
     
  12. Cabin Fever

    Cabin Fever Life NRA Member since 1976 Supporter

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    I do not think this is accurate. New stoves burn more volatile gases as the gases leave the firebox which would result in higher exhaust temps. I believe a catyst will only operate at very high temps (>500ºF). If anyting, it would be the older, less effecient stoves that would operate at lower temps.

    Suitcase Sally: As far as your thermometer problem goes, I'm wondering what kind of stovepipe you have. Many installations use double-wall stovepipe. A stovepipe thermometer will only work with single-wall stovepipe.
     
  13. RedneckPete

    RedneckPete Well-Known Member

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    I run a stove top temperature between 600 and 900 degrees. I have about seven feet of single wall stovepipe on top of that, which I'm sure cools the exhaust a fair bit before it gets into the chimney. I've never had creosote problems, and I burn a fair bit of softwood.

    In my experience, wet wood makes it difficult or impossible to get the stove up to temperature. Combine a cool stove with lots of water in the exhaust and you have a recipe for disaster.

    Trust the thermometer, question your burn techniques.

    Pete
     
  14. GREENCOUNTYPETE

    GREENCOUNTYPETE Moderator Staff Member

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    i was just at my parents this weekend for christmas and was running the wood stove in the basment they have always had a thermomiter it is marked of to have optimum burn at about 400 to 450 it sitts about 20-24 inches from the top of the stove

    but i have definitely heard that exhaust should leave the chimny at 200
    and the better insulated the chimny the less actual energy need be put up the flue to keep it 200 degrees

    one of the guys at work was talking about a digital thermomiter with thermocouple that he cemented into the flue and he can get accurate flue gas temps as well as it has a siren set to 800 degrees warning him of impending chimy fire or over load of stove

    what prompted him to do this was that his son had loaded the stove but had put in some rotten wood if you have ever burned a piece of rotten wood you know that it will spike you stove temp because it burns so fast
     
  15. stanb999

    stanb999 Well-Known Member

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    I did say NON-CAT stoves. Not stoves with cat.
    The reason that the non-cat stoves don't raise the flue temp is due to the rather extensive baffeling and very low air flow. The temps. inside the stove can exceed 1200 degrees. This is much higher than that of other stoves. Due to this the manufactures must design the stoves to keep the super heated gases in the burn chamber. The burn chambers are infact "insulated". But the flue temps are generally low.
     
  16. stanb999

    stanb999 Well-Known Member

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    Hey think of this. The UPC stickers on the stove pipe have been in place since installation. They are just a little brown. And before anyone asks.... I clean the chimney once a year and get almost nothing out. Also we burn about 10 cord a year.
     
  17. Cabin Fever

    Cabin Fever Life NRA Member since 1976 Supporter

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    I have two "not-cat" stoves that use secondary combustion to make the stove more effeicient. The air baffling is near the outlet (top) of the firebox. This secondary combustion burns volatile gases that would not normally be burned in an older woodstove. These gases are being burned just before they exit the firebox which results in higher, not lower, exhaust temps. If the manufactures designed a stove that caused the "superheated gases" to stay in the firebox longer (as you described) the firebox would be under pressure and would result in smoke and gases being spewed into the room everytime you opened the firebox door.
     
  18. stanb999

    stanb999 Well-Known Member

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    Well yes and no. The gases are generally propelled around the burn chamber in one of two ways. Some stoves use a front to back air flow. Some side to side. This prohibits the easy flow of air up the flue. With a proper design the greater the air imput the greater the rotational flow. This has the firestorm effect you see in your stove. When it's burning really hot due to "damper" position the fire has a tendency to stay in the fire box.
    In an older stove the fire has the tendency to go up into the flue. This greatly increasing the flue temp.

    If you haven't seen the "fire storm". Get the stove good and hot. Carefully open the stove door. Put a couple of thin/dry pieces kindling. Dump the stove back but only about 80%. Give the stove a few minutes. You should hear the stove starting to ping and the fire storm start. The reason this happens is the volital gasses get driven out of the wood in an instant. These gases will burn with amazing speed and heat. Try it. :)