Flue temps with probe vs. surface temp

ddahlgren Posted By ddahlgren, Jan 23, 2013 at 9:58 AM

  1. ddahlgren

    ddahlgren
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    Using a probe type thermometer vs. a surface mount like rutland and others what temps do you shoot for with the probe type? I have one due here today and will install and need to know logical numbers to shoot for. How low will creosote and how hot is an over fire with a probe?
     
  2. Diabel

    Diabel
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    Every set up will be slightly different. Flue temp on mine will run from high of 500 to low of 350 in the first six hours.
    Stove top temp will sit around 600 during this time.
     
  3. ddahlgren

    ddahlgren
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    That seems logical. I am looking for a do not go under number if you can help to stay away from creosote and a not to go over one on the hight end. I am guessing they are greater than the numbers on the surface mount thermometer.
     
  4. pen

    pen
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    No need for both, just a quality one or the other depending on your setup.

    After doing a lot of playing around, if you have single wall pipe I suggest magnetic surface (not rutland). If you have double wall, then a probe thermometer.

    pen
     
  5. Jags

    Jags
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    I second what Pen is saying. For a real world comparison it is about a 2:1 increase. Surface reads 300 - probe will read about 600. 400/800, etc.

    Edit for clarification: This is only taking the stack into account. By surface, I mean surface of the stack, not stove. Hopefully I did not confuse anyone.
     
  6. oldspark

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    Is that a probe?
     
  7. Diabel

    Diabel
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    Yes
     
  8. oldspark

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    Seems low I run those temps on my surface thermometer.
     
  9. Ashful

    Ashful
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    So... what's reasonably hot for a surface probe (or IR gun) on a single wall? 300'ish? I've had mine waaaaaaay over that, in the course of getting my cat stoves warmed up in bypass mode.
     
  10. Diabel

    Diabel
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    In bypass mode....different story, if I let it go.... I can clean the clue pretty fast, pegging the thermo!!! In bypass mode never leave the stove unattended !
     
  11. oldspark

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    The safe range on a surface mount thermometer as marked and I consider a good guide line is 250 on the low side and 550 on the high side, I spike way over that at times with no problems.
     
  12. Jags

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    Don't run over 1100F internal or 550F surface. The stack can handle bursts higher, but those are the numbers for sustained temps. I highly recommend keeping it lower than that for sustained temps (like peak up to 8-900 on start up and then cruise it down lower, what ever that temp might be). Each stove and setup will likely have a different cruise temp on the stack. Mine likes 500-650 when cruising.

    Edit: we posted at the same time, Sparky.;)
     
  13. madison

    madison
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    Ditto Pen's suggestion. IMHO a stack thermometer is sorta like having a tachometer in an automatic transmission car -- interesting to watch - but not really necessary.
     
  14. ddahlgren

    ddahlgren
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    I found the rating of the duravent Plus 1000F continuous 1400 for an hour and 3 shots of going to 2100. So my next thought what temperature to try to stay above to avoid creosote?
     
  15. Jags

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    Water is steam at 212F. Keep it above that. During the out gas stage, I try to keep above 450F (internal/probe). Coaling stage doesn't matter much. Not much nasties left in the wood. This is just my opinion and how I do it. No facts to back up the process, but it has worked for me and keeps a clean stack.
     
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  16. oldspark

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    Oh contrar, good idea to know if flue temps are too low or too high, a lot of people burn questionable wood on here and the best way to do that is keep the stack temps up.
     
  17. oldspark

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    250 to 300 surface, not sure if the thermometer manufactors are erroring on the side of saftey or not.
     
  18. Trilifter7

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    I use my surface temp meter on the flu as my guide for when to close the bypass damper. I typically run the surface temp up to around 500-550 on the flu then close the bypass. It's a good gage as to how intense the fire is in the stove.
     
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  19. ddahlgren

    ddahlgren
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    With the particular Rutland surface temp thermometer I have struggled to get over 320 with a blazing kindling fire going that fills the glass for an hour the reason for the probe type. So much for the Rutland crap..
     
  20. oldspark

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    Well I have a rutland, they are not that accurate but usually are close enough, did you check it with a IR testor?
     
  21. Ashful

    Ashful
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    Yeah... but who's connecting their chimney liner directly to their freestanding stove? Most have a stovepipe, likely most often single-wall, and you can drop more than 100F over the length of that stovepipe.
     
  22. Trilifter7

    Trilifter7
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    My Condar is typically within 50* of what the IR meter shows. Normally it's around 50* cooler than actually surface temps
     
  23. Jags

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    I believe those numbers hold true for the stove pipe as well because you are measuring the temp at the stove pipe, not in the liner.
     
  24. pen

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    Remember, to prevent creosote, you need to keep those temps over 212 all the way to the sky
     
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  25. corey21

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    I have a probe it likes to cruise at around 400.
     

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