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Is this Flue Temp Probe Full of "It"?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by pen, Jan 21, 2010.

  1. pen

    pen There are some who call me...mod. Staff Member

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    I received Wess's address so it went in the mail today. I am betting only a few days at most from Pa to Ma so we'll find out shortly.

    pen

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  2. Troutchaser

    Troutchaser New Member

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    I did pull the probe out a couple inches last night to see what effect it might have. The temp. indication dropped about 100 deg. in just a few minutes. Of course, I had two inches of probe sticking out of the pipe, but maybe this is a more accurate reading?
    I wonder if this is better than cutting it off.
  3. Todd

    Todd Minister of Fire

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    Yeah, after cutting an inch off mine and watching it all day I can say mine dropped about 100 degrees from what it use to read and is pretty much double the external temps, still more than the 50% Condar states it should be. It's also pretty much resembles my stove top temps after everything settles in.
  4. 3fordasho

    3fordasho Feeling the Heat

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  5. Todd

    Todd Minister of Fire

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    Any word from Condar yet?
  6. pen

    pen There are some who call me...mod. Staff Member

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    no word today

    pen
  7. pen

    pen There are some who call me...mod. Staff Member

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    I didn't cut mine short, but instead moved it up the pipe in the 90 degree elbow. It's readings are more believable now, but still I think it is reading high. Definitely much higher than their claim of being about 50% higher than the pipe temp.

    Maybe it is too much to expect to be able to follow the directions on a product and get predictable results.

    If they say 18 inches up the pipe, that's what I am going to do. If that's not where it needs to be, then it's just a guessing game.

    Now for me, I know what is going on w/ my stove even w/out this. But being a curious nerd-type, just wanted a new toy. The guy I feel sorry for is the first time wood burner who is reading this thing like gospel. If I were to read this like gospel, I would never see a stove top temp above 450, because any fire above 450 at the recommended height above the stove put things into the "too hot" zone.

    pen
  8. begreen

    begreen Mooderator Staff Member

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    Hey, that's great. I've always said I was going to get a Tel-tru surface thermo if my Sandhill ever died. But I didn't know they made a high-temp probe at a reasonable cost for a barbeque. It looks sharp. I like white dials behind glass. This is how the Sandhill is made. Is it magnetic on back? If not, how is it held in place on the vertical pipe?
  9. 3fordasho

    3fordasho Feeling the Heat

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    Not magnetic, just a simple .150" diameter stainless steel probe. I drilled my double wall pipe and tapped it 1/8 pipe thread. Took a brass hose barb, (1/8" male pipe thread- 1/8"id hose barb and drilled it out a bit for the .150" probe.

    [​IMG]
    [​IMG]
  10. Todd

    Todd Minister of Fire

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    Great idea Tim. Do they make a thermometer that reads a little higher? I know you pegged yours a few times and that's what I'd be afraid of since I can easily go over 1000 in bypass mode.
  11. 3fordasho

    3fordasho Feeling the Heat

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    1000F is the highest they go. In start up or reload mode I like to keep it at 600F or less. The two times I've had the needle pegged were when I forgot about the stove for 5-10minutes and had the air full open. Both instances were enough to ignite the small amount of build up I get in my 2- 45degree dbl wall connector pipe sections. Not full out chimney fires by any means but enough that it got your attention both in smell and a bit of visible smoke off the pipe. Due diligence is required with the air control during start up/reload (bypass open) and then no problems keeping the thermometer in it's happy range.


    I know we've had previous discussions about cruising flue temps and mine seemed quite a bit lower than what you were seeing.
    I did have one thermometer that was reading low and I replaced it. Both my fireviews run about the same, 400-500F flue temps in cruise mode (load of wood, stove top 300-550F, cat engaged). FWIW the tel-tru that was reading low was easy to recalibrate once I got a new one to compare with. Not all their thermometers can be recalibrated, the one in the link I provided above can be.
  12. Highbeam

    Highbeam Minister of Fire

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    But how do you know Todd? I'm thinking that we are going to have a whole new idea about our flue temps once proper measurements are taken. Perhaps you've never exceeded 600. Ever. None of us can possibly know what our flue temps are or have been based on the condar meters. Only the thermocouple guys can really be certain.

    Maybe after we get some feedback from Condar we will be able to adjust the dial reading on our condar probes to be accurate. In looking at it there are several hax head nuts holding it together which should be easy to loosen up for adjustment.
  13. Todd

    Todd Minister of Fire

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    Good point, just like peter stated earlier the higher the Condar temps go up the more inaccurate they seem to be.
  14. 3fordasho

    3fordasho Feeling the Heat

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    Good idea on the thermocouple check, that's exactly what I did that let me know my condor was reading several hundred degrees lower than actual flue temp. Because the bi-metallic coil is outside the pipe on the condor, the whole single wall vs double wall has a big effect on the reading and I can't understand how condor can say their thermometer will work for both. To complicate matters, if the condor is installed in an adjustable section of double wall connector pipe (like mine was) there is a good possibility there will be four layers of metal (were the telescoping sections overlap) and the reading will be even farther off. The one I had installed would rarely read over 250F in this situation. With the tel-tru thermometer, the entire bi-metalic coil is housed within the stainless steel probe tip, which is itself entirely inside the flue pipe. I believe this results in a much more accurate reading at the expense of durability if you go over its intended temp. operating range.
  15. pen

    pen There are some who call me...mod. Staff Member

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    It has been 1 week, and I have not heard back from Condar as they initially promised.

    Here is the letter that I sent to them this morning.

    Good Morning,

    I sent an original email message to Mike Whitt last Friday, who forwarded it on to Carolyn, who said they would get back to me on Monday (1/25/10) to help me understand the following.

    Basically, the box for my fluegard thermometer explains that I should expect temperatures to be 50% higher than my stove pipe readings. However, here is what I was reading when installed 18 inches up from the stove collar.

    [​IMG]

    As you can see, my stove pipe is roughly 300 degrees. 300 + 50% and I would expect the condar to read approximately 450. However, it’s maxed out at the safe operating temp.

    This picture was taken about 1 hour after the stove was dampened down from initially loading it. It was essentially “cruising” at this point, so the high temp on the probe is not from a sudden increase in flue gas temps.

    Additionally, I tried testing this a different way and received the following results

    [​IMG]

    Please help me understand why this is reading so high. Additionally, at complete room temperature, it appears that the dial is reading correctly, pointing pretty much exactly at the F at the bottom of the scale.

    Thank you,
  16. redhotz

    redhotz Member

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    Maybe you should let them know that there are thousands of people in this site waiting for an answer........ :coolgrin:
  17. pen

    pen There are some who call me...mod. Staff Member

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    Just received 2 speedy responses.

    Here they are

    Hi Matt –



    I’m planning on asking our VP of manufacturing review this but he’s been out-of-town most of the week. He’s supposed to return to the office today. Hopefully we can get you answer shortly.



    Regards,



    Mike


    AND

    Matt,



    I forwarded your email for them to get back to you.



    Eddie Taylor
  18. Peter B.

    Peter B. Feeling the Heat

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    Just to stir the pot, here is some other confusing/conflicting material from Condar's web site.

    --

    On the stovepipe surface thermometer directions for use page there are these guidelines:

    --

    On the flue probe thermometer directions for use page there are these guidelines:

    --

    So... according to Condar, 230 surface equates roughly to 400 flue internal, and 475 surface to 900 internal.

    But 400/230=1.73 and 900/475=1.89... factors which are neither 1.5 nor 2.0.

    --

    Yesterday, using a Condar surface thermometer and a Condar flue probe at about the same height on single wall stovepipe, most of the comparative readings I took showed the flue probe temp at 2x (or greater) for a given surface temp. The relation ranged from 1.8 to 2.5 at normal burn temperatures (230*-340* surface / 420*-780* internal).

    No, nothing conclusive here... move along now people.

    Peter B.

    -----
  19. ckdeuce

    ckdeuce Feeling the Heat

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    Forgive me if someone already asked this..... But..... Did you try using your IR thermometer through the hole that the probe goes through? It might not give you true gas temp, but it will give you the temp of the inside wall of the pipe. Maybe yank the probe (no pun intended) out of the hole and shine your IR into the now open hole (no pun intended).
  20. Battenkiller

    Battenkiller Minister of Fire

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    Won't work. The sensor is behind the lens of the unit, not the laser pointer. The hole would have to be bigger than the lens itself, at least 1/2".
  21. begreen

    begreen Mooderator Staff Member

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    By the 50% higher calculation, 230°F surface should read about 345°F probe temp. 475°F surface should equal about 713°F probe temp.
  22. Todd

    Todd Minister of Fire

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    Ah I see they never got back to Pen or anyone else, I'm not surprised, any word from Wes999 on that side by side test with his thermocouple?
  23. pen

    pen There are some who call me...mod. Staff Member

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    They keep promising that the people in the "know" will get back to me.

    My probe was received by Wes (that sounds terrible) and is going to play with it (still sounds terrible) this weekend if time allows.

    pen
  24. Todd

    Todd Minister of Fire

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    :lol: :lol: :lol:
  25. pen

    pen There are some who call me...mod. Staff Member

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