Is 1200* dangerously hot?

[pen]

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

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

 

[Jags]

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

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]

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.

 

[pen]

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.

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]

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

 

[pen]

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

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

 

[nate379]

You guys got me curious so I just checked.

Right now stove top is 450-475* which is what my IR gun says and the Rutland T Stat says 450*.

The outside of the double wall flue is 180* near the stove and 125* up toward the ceiling. It's cool enough that I can put my hand on it and it's not burning hot.

 

[begreen]

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

https://www.hearth.com/talk/threads/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.
(broken link removed to http://www.teltru.com/p-254-gt200-back-connect-thermometer-1-34-inch-dial-with-18-inch-npt.aspx)

 

[GunSeth]

I just installed my probe thermometer a few days ago. So far it peaks between 900-1000 when I get a fresh load cranking. After I cut back the air in drops down to the 600-800 range very quickly.

 

[NH_Wood]

Here we go again! I'm in the same situation as Pen. My condar probe (18" above collar) is always climbing to at least 1100, and often settling at 900. I will get stovetop temps as normal range - up to 550-600. I will read very high probe temps when the firebox shows a nice, lazy show of secondaries - in other words, by looking at the fire, things are just fine - no super hot stove top, etc. Also, the other day, I got the probe to 1300-1400 because I was on the computer doing some reading (yes, you know where), and forgot to close up the primary. I was thinking 'why no glow, or discoloration?". I have come to put very little stock in what the probe is telling me - I watch the characteristics of the fire (foremost) and the stovetop T - I check the probe for fun. Cheers!

 

[Renovation]

Easy folks you are jumping the gun here. We've been down this road before. I had a dozen emails w/ a big wig at Condar regarding this and even sent the probe back to him to re-test in his thermocycler. Wes on this site also tested it against his thermocouple and on his stove.

The cliff notes of the saga from last winter (which you guys must not recall or missed) was that condar is erring on the side of cooler flue temps. We agreed to disagree about the validity of these on single walled pipe as they claim. We agree that they are accurate in his testing rig, but I don't think they take into account a real world situation regarding the radiant heat of a single wall stove pipe.

On double wall pipe, I would be more apt to believe the readings are closer to true values and not go to 1200.

https://www.hearth.com/talk/threads/51149/

pen

+100

This comes up over and over. Pen has carefully proven that the Condar probes read high--they are repeatable, but their numbers are garbage and misleading.

There are regularly posts like the OP's, where people are mislead by the Condars' numbers, and are needlessly concerned and/or running their stoves below maximum output out of needless fear of overfiring.

Diligence is a wonderful thing, and it's a shame that Condar probes reward it with needless anxiety. But they're still useful if you ignore the numbers.

 

[Todd]

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

https://www.hearth.com/talk/threads/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.
(broken link removed to http://www.teltru.com/p-254-gt200-back-connect-thermometer-1-34-inch-dial-with-18-inch-npt.aspx)

I think those Condars are junk! It's not a true probe because it has the windup coil thingy behind the dial. I like the looks of those teltru but the temp range seems low and I remember someone here who pegged one out and wasn't sure if ever read right afterwards. You would think there would be something better for wood burners?

 

[Todd]

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

 

[Peter B.]

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

-----

 

[pen]

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

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

(broken image removed)

Stovepipe thermometer

(broken image removed)

pen

 

[pen]

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

-----

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

 

[JotulOwner]

I normally see pipe temps of 400-600 degrees. I try to keep the temp above 400 to prevent creosote buildup. I have seen temps as high as 900. From what I have experienced, once a fire is really cranking, cutting back on the air supply will raise both stove temp and pipe temp. The only way I have found to prevent this is to cut back the air supply before the stove gets too hot.

 

[Peter B.]

pen:

I have a 20 year old Condar probe that I trust as reasonably accurate. I believe BeGreen has one of the same vintage that he also trusts.

If they can both (still) provide some measure of accuracy, why do you continue to defend the current Condar probes as 'consistent'... even though they may be?

I'm definitely not slamming you, but I'm sure you can appreciate the (obvious) importance of (reasonable) accuracy from a device the manufacturer touts for its accuracy.

I wouldn't be apologising for Condar, if I were me.

PB

-----

 

[Peter B.]

(attempt to delete double post)

 

[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

 

[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

 

[firefighterjake]

Random thoughts . . .

Thanks for the reminder Pen . . . I forget that not everyone who uses a probe style thermometer is running it on double wall pipe . . . as you said . . . in those cases the temps may measure a little more accurately . . . although I suspect as you discovered that the temps are still not very exact.

I do know that I tend to use the probe style thermometer as a rough guide . . . I tend to run the stove in the middle of the "safe" zone . . . that way I figure if the probe is running a bit higher or lower I should be OK . . . that and I also run the stove based on BOTH the readings I get from the probe thermometer in the stack and the stove top thermometer . . . together the two temps give a bit clearer picture of what is going on, where I am and where I am going with the stove.

I am still a big proponent of thermometers with woodstoves . . . and perhaps some day may lay down some serious coin for a very accurate thermometer . . . in the meantime the cheaper thermometers work for my purpose . . . and I suspect in most cases will help most folks get have an idea of what the stove and stack temps are at.

 

[begreen]

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.

 

[pen]

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

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

 

[begreen]

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