In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Thermometer location

Discussion in 'Non-EPA Woodstoves and Fireplaces' started by Mad Adder, Feb 1, 2018.

  1. Mad Adder

    Mad Adder

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    Quick question on my Jotul #4. Where should I place my thermometer? The Jotul has a rear draft door which I close to 45° when running and usually run the door draft 75-100% open. This gets my pipe temp to a max of 450-500°. Cranks heat out, but goes through wood. I'm reloading about every hour, but heating whole house with cellar door open. My fear is running to too hot if the rear draft is half closed. I' guessing that' to help burn smoke better. IDK. Where is best, pipe or top of stove?
     

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  2. Mad Adder

    Mad Adder

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    Running wide open with logs was just under the line. I added a few sticks of kinlin and was able to push it a bit over the line. I think I'm safe for the most part.

    I just went to the stove. On the pipe, the thermometer was reading 200°F. I moved it to the corner of the stove and waited. It settled out at 350°F. Where should I monitor for burn rate window?
     

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    Last edited: Feb 1, 2018
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  3. Coaly

    Coaly

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    That is a magnetic stove pipe thermometer. It is calibrated to read pipe surface temperature which is about 1/2 of actual flue gas temp.

    The object is to keep flue gas temp above 250* f. to the top of flue. That is the condensing point inside where water vapor condenses on the walls allowing smoke particles to stick. Flue temperature must be above that critical temperature while smoke is present.

    So your chimney dictates the temperature you need to monitor on the pipe before it dumps into chimney. If the flue size increases larger than connector pipe and stove outlet, flue gas expands and cools considerably. (about 1/2 the temperature drop from 6 to 8 inch diameter) So it is best to check temperature just before chimney at breech. If you have an indoor insulated prefab chimney that requires the least amount of heat, estimate a temperature drop of about 100* to the top, the less efficient the chimney, the hotter it needs to be to maintain 250* to the top. Notice the temperature graduations on the thermometer starts at 250* for the lowest permissible temp, which would be 500* flue gas usually measured on the first section above stove. That is an estimated heat range where creosote would be produced in an outdoor masonry chimney. The easiest way is to measure temperature at the top with an IR thermometer so you know the exact temp at the top and compare to the pipe temp at the bottom. Then you know what temp is required for your particular chimney.