Is 1200* dangerously hot?

BeGreen said:

Methinks we need another round of Condar probe checks. This may be another case of significant error at the high end of the scale.

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I think it's a problem where they test accurate in thermocyclers but the accuracy at home depends on your setup. I think "real world" testing should be done at condar instead of using a damn electric machine.

For those who haven't read the thread that I linked to, check out this picture and maybe you'll begin to agree w/ me that the environment where these probes live varies and as a result so to do their readings.

Remember, the probe seen here went back to condar and testing "near perfect"

pen

oldspark said:

Jags this is funny as my posts last spring were about my being worried about my high flue temps and I was told not to worry about it on reload and start up

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Even after running my setup for years - if I saw a 1400F temp on my probe thermo, I would be more than nervous. I would be down right scared - and I ain't scared of nothin'.

Edit: but as Pen is showing us - not everything is as it seems.

DonNC said:

I use double wall pipe and during this first week I have been taking many readings on my IR

I cant tell you what the temp is inside the flue, but Im checking the outside temp simply because that is the part that is closest to combustibles ...and up at the ceiling it is those tamps that heat up the trim / support box.

I got that stove up to 650 twice now and during that time the hottest part of the pipe (at the damper/adapter and at the connection to the support box) was at 350 and 288 respectively.
I usually run the stove in the 450-550 range and the pipe temps never get out of the 200's. Good enough for me. It is this pattern that I will judge future performance by.

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Remember, your double wall will shield that probe a lot. I would be much more apt to believe the temps on a probe installed in double wall pipe.

You sound like you are doing fine but burning on the cool side of stove temps. Just keep an eye on the chimney and cap, if they start getting buildup reconsider your strategy.

pen

DonNC said:

Pen

I have a stove top thermometer and an IR gun. Sometimes they differ on the stove top by 50 degrees or more. I tested them on a cookie sheet in the oven and they were perfect...spot on. Im glad you put the old mercury thermometer in there to settle it.
Did you show those picks to the manufacturer? They said it tested perfect but obviously its not perfect. After seeing your pics I wouldnt recommend that make/model to anyone

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yep, they saw them. Actually their customer service was great and we just ended our conversation regarding differences in burning philosophies that we each have. Essentially they feel that if you are going to err, they want it to be on the too cool side.

I still think its a very valuable tool just the numbers need to be taken w/ a grain of salt. On one stove 1000 may really be the max. On another, it could be 1300 because of added variables.

pen

Besides Pen's nicely detailed tests we should remember of how it compared with a thermocouple reading:

https://www.hearth.com/econtent/index.php/forums/viewthread/51880/

I don't mind a small margin of error, but when the error is 25%, the value of such an instrument is limited IMO. If I felt ours was that inaccurate I'd lose it. When or if I buy another, it is going to be a calibrated digital or a dial instrument from TelTru.
http://www.teltru.com/p-254-gt200-back-connect-thermometer-1-34-inch-dial-with-18-inch-npt.aspx

Todd said:

Here's another flue thermometer from Morso but I think it's for single wall. Compared to my Condar magnetic external thermometer the Morso numbers are a bit different.

http://www.morsoeusa.com/Flue-Gas-Thermometer-501.aspx

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that's a magnetic thermometer, not a probe.

The numbers are different compared to rutland mag thermometers because a rutland scale is a blend between what is safe on the external parts of the stove versus the external parts of the stove pipe.

If you look at the condar magnetic thermometers on their website you can see the differences.

Ah hell, here's the pics don't go to the website.

Stove Top Meter



Stovepipe thermometer



pen

Peter B. said:

I will chime in once again because I was one of the 'principals' in the thread pen has cited.

Since that thread was current, there have been any number of others that have cast the accuracy of the Condar probes into doubt.

I remain convinced that Condar's flue probes do NOT reflect real world internal flue temperatures.

Not no way, not no how.

I've done my own 'round' of tests with multiple probes and they have all read high - anywhere from 200 to 400 degrees high.

pen is right - they are consistent - consistently inaccurate.

I'm inclined to think there's room in the marketplace for a manufacturer who can offer an ACCURATE probe.

PB

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I really think the biggest problem is the radiant heat from the pipe. If I could just find that metal cup I had already drilled a hole in for the water bath test I'd put a bunch of rock wool in it, insert the probe through that, then into the stove and see if it makes a difference (I could do it w/ a soup can but I've been too busy). I think it would. I just haven't gotten around to trying it yet. It was easier to test / compare when I had the 2 probes. They didn't send my probe w/ a damaged face back to me.

pen

PB, good question. Maybe what I mean by consistent is not clear. What I mean is that for my stove w/ the thermometer in the location I have it, if I let it go over 1250 degrees on the probe on a fresh load the stove will get hotter than I want it. If on a fresh load I start cutting the air back at 900 on the probe and have it closed to my "cruise" position by 1100 to 1200 on the probe, the stove top stays under 700 for me. 15 - 20 mins after 1100 to 1200 is seen on the probe thermometer it will be reading around 1050 to 1000 or so.

So for my burn cycles, the probe reads consistently.

I just don't understand what changed between the old and new thermometers. A visual inspection shows they look identical to me. Tim at condar said the same but who knows.

In all it's like the car I used to have where I put new rear gears in it. After the gear swap the speedo read about 20% higher than it should have. I just got used to it. Same thing with this probe.

Does that make sense?

I have a new test going, give me a little bit to post the pics.

pen

Alright, I hope none of you are trying to use 56K

This is a picture of the probe thermometer w/ the stove top at 575 about 1.5 or so hours after being loaded. I don't think that's over running this stove at all, but according to this thermometer I am. Also, my probe is placed about 28 inches above the stove top (10 inches higher than they recommend). It would be reading even higher if I had it down at 18 inches.



This is a picture of the insulator I made. Not only does it pull it away from the stove but its surface temp is only about 150 degrees. That's probably about what you guys w/ double wall pipe would find I imagine.



After the first picture I put 2 med pieces of wood on the stove and kept the air the same. I gave it time to burn down and heat up the clay pot bottom. The stove went up to about 650 and this picture was taken when it was down almost to 575 (a little above). I would say this data looks a little more reasonable for a 575 degree stove. The real test will be how it reacts tonight when I load up the stove for bed. I included the IR meter just so you can get an idea of what my surface temps were in the area at the same time. What I find funny is even with this shield and even being higher than recommend and even having less of the probe in the pipe, this thing still reads far higher than the 50% higher claim their packaging includes.



Do you guys now see why I don't get worried when this thing hits 1200 on my stove? Key words being my stove and that is where my beef lies. How many inexperienced burners are taking these readings as gospel and thinking their under seasoned wood is burning in the "normal" zone and instead are burning far too cool and building up creosote in the stack.

pen

I have no problem with relative numbers as long as they are stated that way. Trouble is that although we commonly see questions about flue temps, rarely do we see complete disclosure about the temps like: I am seeing 1200F flue temps, but this is with a probe that I don't really trust, oh and it's on a single-wall pipe.

One can see how this might be constantly confusing newcomers and pushing sparks to a headache. Confuses the heck out of me also. I see too many posts to remember who has what probe on what flue. Maybe add it to your signature.

PS: Pen, thanks for your persistent and interesting tests on this topic.

BeGreen said:

PS: Pen, thanks for your persistent and interesting tests on this topic.

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I just wish I create a scenario for this thing to operate as it is advertised.

I agree that it's a lot like getting into a car and having it be a crap shoot if the speedometer is correct or not. If you have a lot of experience driving, you'd be able to make an estimate quickly and adjust according to what experience tells you based on observation. But if it's your first time driving???? ugh.


pen

Considering how radically different our readings are, if you'd like, I could send you my old style Condar to compare with.