# Condar Temp Probe vs. The  Thermocouple...



## WES999 (Feb 1, 2010)

Ok, here is the results everyone has been waiting for.

Pen sent me on of his Condar probe type thermometers.
This model is basically a by-metal spring type thermometer (like the magnetic ones that you would put on the stove top), with a metal rod that protrudes in to the flue.

One thing, the probe Pen sent me was the one that arrived to him damaged. Pen unbent the dial face but  the pointer looks like it may be slightly bent. The pointer seems to be a bit toward the cooler side, so a undamaged one may possibly be less accurate than this one. 

I installed the Condar right next to the thermocouple on the single wall pipe of my Fisher stove. I tried to have the temp stable on the controller to allow for the slower response of the Condar when I recorded my readings.

What I found was the Condar was reading 100 °F  to 200 °F higher than the thermocouple.

Her are some readings: 

Thermo                Condar
600                      700
650                      800
750                      900
800                      1000

The Condar is more accurate at lower temp and gets less accurate as temp increases.

All in all, I would say for the price it's  probably good enough to give a reasonable approximation of flue  temp, but certainly not a substitute for a thermocouple type probe.


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## Todd (Feb 1, 2010)

Thanks Wes. I knew these probes seemed to read high. I see you have an external there as well, was it pretty much reading half of what the probe was? Mine reads double til the temps get up over 800 then it seems to run away from my external.


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## ggans (Feb 1, 2010)

Where did you get that alarm..


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## WES999 (Feb 1, 2010)

The one in the pic is from IMS co. , they are kind of expensive about $300 without a thermocouple.
I built my own for about half the cost.


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## ggans (Feb 1, 2010)

Nice.. thanks..


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## pen (Feb 1, 2010)

That is pretty much exactly what we figured it was doing.

Thanks for the conclusive test at high temps.

The needle on my other probe appears to be pointing straight towards the center of the probe (perpendicular) on the left side and tipped to the left on it's right side.

I hope condar gets back to me soon.

pen


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## Peter B. (Feb 1, 2010)

Thanks pen and Wes for setting up the test...

Pretty much confirms the suspicions I had but couldn't prove.

I guess it's not 'definitive' since it was only a sample of one Condar probe, but a few other people have reported high readings with the FluGard, so there does appear to be a pattern.

Seems to me Condar must be aware of this... or you'd think they ought to be if they test an occasional probe that comes off the line.

I'm still curious to hear what they'll have to say.

Strikes me that there might be a market for <accurate> probes.

Peter B.

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## pen (Feb 1, 2010)

Peter B. said:
			
		

> Thanks pen and Wes for setting up the test...
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No not definitive, but remember, the probe that Wes tested was the first damaged one that was sent to me.  I received a replacement because of the squished face.  Both thermometers read identically.   Again, not conclusive, but I am confident that if I put my "pretty" probe in the same test that Wes did, it would read exactly the same.

pen


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## Peter B. (Feb 1, 2010)

pen said:
			
		

> Peter B. said:
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pen:

I wasn't disputing or doubting...

On the contrary, I'm pretty much convinced my own FluGard reads 200* or more high at temps above 500*.

Wes' test and others reporting high readings all seem to bear out what I've observed myself.

Peter B.

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## pen (Feb 1, 2010)

Peter B. said:
			
		

> pen said:
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I am truly disappointed I can tell you that.  I really don't understand why they are so off.  The mechanics are quite simple, but most importantly, consistent!  I am consistently getting results that don't match the readings on the face, by the same amounts.  This means that the error could be fixed by changing the scale on the dial.

Seems like a simple solution to me.  

I really wish they'd respond as I am anxious to hear their explanation.  

pen


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## Peter B. (Feb 1, 2010)

I don't mean to be pouring gasoline on the flames, but...

The high reading tendency appears to be shared by Condar's (2009 issue, 4") cat probes as well... which are generally 'in agreement' with the FluGard.

I have a cat probe located immediately above the catalyst itself... and I don't get reliable light-off until the probe reads about 1000*... some 300-400 degrees higher than the presumed actual light-off temp.

And yeah, I'm disappointed too.

Since with my stove I can't see either the fire or the cat in operation, pretty much my only guide(s) for monitoring the stove are thermometers... so I tend to rely on them more than someone who has visual cues from the fire itself.

And constantly having to 'extrapolate' actual temps from inaccurate thermometer readings is pretty annoying, frankly.

I'd gladly pay twice what the Condars cost me if I could rely on the readings.

Peter B.

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## Highbeam (Feb 1, 2010)

We can play with percentages now.

So when the condar reads 1000 the actual temp is 800. This means the gauge reads 25% more than 800 or it is off by 25%. I suspect that when the internal temps really do approach 1000 that the error is even higher. The gauge should read accurately over the normal operating range of a flue which is room temp to 1000. After 1000 I could learn to live with an error since I hope to never go that high and once I do it is not too important what the actual temp is. 

So perhaps it is a 30% error at 1000 true temp. That doesn't quite jive with the specified "less than 5% error" on the documents. 

I am glad that the low end is more accurate since that is the creosote stage and the high end is conservative which may be intentional. The manner in which this meter is inaccurate reeks of a liability lawyer.


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## pen (Feb 1, 2010)

The box says to add 6% to the value shown on the thermometer for horizontal installations, just to make matters even worse.

pen


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## jasong (Feb 1, 2010)

I have a Condar flueguard probe and digital thermocouple alarms on stove and flue. What I have seen with the Condar is that it is extremely slow on how fast it registers on the dial. The digital one is pretty much instantaneous and can be several hundred degrees hotter than the condar when starting up. Once the fire is established and I close the air and the fire stabilizes the Condar will catch up and show what the digital thermometer shows. Even on a slow die down of the fire the Condar will register 30 or so degrees higher due to how slow it registers. When I got the Condar I  stuck it in the oven to check its accuracy. It was off so I loosened the nut on the face and adjusted the dial to match the oven temperature.


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## Highbeam (Feb 1, 2010)

"When I got the Condar I stuck it in the oven to check its accuracy. It was off so I loosened the nut on the face and adjusted the dial to match the oven temperature."

That's really too bad. It is not proper to adjust it that way since the condar is NOT an oven thermometer. However, using your thermocouple you could do a good job of adjusting it. Was it pretty easy to spin the face of the condar?


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## jasong (Feb 1, 2010)

I needed a good steady heat source that I new the temperature of. It worked well. It was kind of a pain. when it's loosened you can match the dial to the actual temperature. It was a little hard to hold it in place while tightening it back down.


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## pen (Feb 1, 2010)

Here is the response.

Wes, I am writing a reply now and will be using your readings also.

Dear Matt,



I’m sorry it’s taken a few extra days to get an answer to you, but I was out of town most of last week.  Mike Whitt told me he did speak with you on the phone.  I think I can answer most of your questions in both your emails.



First let me explain how our probe functions.  The probe obviously is heated inside the fluepipe and the heat is conducted the length of the probe itself.  The bimetallic coil is located outside the fluepipe, separated by the rivet collar and magnet (you should be using those).  It’s obvious the highest temp is inside the flue and cooler outside the pipe.  The coil measures the temp of the probe at its attachment point and the printed dial face is calibrated to match what is measured inside the heated chamber (fluepipe, with this model).  



If there is no natural cooling of the coil at its attachment point, then the measurement won’t be as accurate.  Your test set-up on your cooking stove shows the probe inside a pan with the radiant heat rising up from the burner; I’d suspect the reading to be higher in that test compared to your digital monitor.



Your description of the operation of your woodstove at its optimum setting with it “cruising” would indicate our reading to be just at the top end of the BEST ZONE.  I would question the infrared reading just short of 300F as that temp is well short of the 400F at the beginning of BEST ZONE.  That would indicate you need more wood or air or both.  The BEST ZONE is a guideline for the operation of most woodstoves.  In other words, based on the operating status of your woodstove at that point in time, the infrared is reading too low.



The infrared meter is measuring the outside of the fluepipe and the FlueGard is measuring the flue gas temps.  Without an extensive study of the hot gases and how they flow up and out, I can’t really offer a reasonable answer as to why there is such a large gap between the infrared and FlueGard.  It does seem from the description of the operation of your stove during these tests, you have it operating as efficiently as possible.  From our experience the FlueGard is more closely measuring the true temps one would expect to see inside a fluepipe as compared to the surface temp you’re measuring with the infrared.  It’s reasonable to expect the outside shell of the fluepipe could be the temps showing on your infrared, but that’s not what the Condar meter is measuring.  



If after all of this, you’re not completely satisfied, you may return the FlueGard for a full refund.  



I thank you for your business.  (I see that the first unit received was damaged in transit.  Do you mind describing the damage so that I can design better packaging if needed?)



Best regards,



Tim Pope

VP


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## Peter B. (Feb 1, 2010)

Call me less than charitable, but that seems like less than a meaningful or direct response.

At least he offered you a refund.

Peter B.

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## pen (Feb 1, 2010)

My Response

Tim,

Thank you so much for getting back to me.

It is truly refreshing to ask a question of a company and receive an earnest response!

Here is a picture of the damaged probe.  It works fine, but is cosmetically trashed.  I believe that the postal service simply decided that this small package be placed under a very large one.  Here is a picture of the damage after straightening out the probe.






I am using the rivet collar and magnet as your directions recommend.  

I operate an Englander 30 wood stove burning well seasoned (at least 1.5 years since splitting) hardwoods (maple, ash, cherry).  The stove is 1 year old, the baffle boards are in tact and the stove operates w/out fuss.  

What I raise question to is the claim on the back of the package that the fluegard will read approximately 50% higher than the external flue pipe temperatures.

I have checked this Rutlands accuracy against my IR thermometer and the two read virtually identical across the board.  The IR has been tested against another I have at work and both read quite similarly.  Essentially, I trust the IR’s temp readings on the single wall stove pipe’s black surface.  As such, when taking this picture (seen below) and the external stove pipe is reading 350, I would expect 350 + 50% to result in a temperature of 525 on the fluegard, not 1000!  This picture was taken about 1 hour after startup so there is no rapid change in flue gas temp as the stove had its primary air adjusted a solid 45 minutes prior and is “cruising.”  

During this time the highest temperature recorded on the stove top is 625 degrees F.  








I had a friend with 2 digital probe thermometers perform a test on his wood stove to compare results.

Here is my damaged fluegard with one digital probe that he has












And the second probe he used for comparison






Using both probes in the setup (for comparison) on the horizontal pipe found in the picture, the following results were recorded.

Thermo           Condar
600               700
650               800
750               900
800               1000

In all, it appears that the Condar fluegard seems to be reading consistently higher than expected by 100 to 200 degrees.  

If I maintain a temperature (at 18 inches above the flue collar) in the Normal zone on the Flue Gard (below 1000 degrees) my stove’s primary air needs to be completely closed and I need to keep the stove top below 450 degrees.  Any stove top temp above 450 and the fluegard will be in the “too hot” zone.

My concern is that if this unit truly is reading too high, that a novice burner, who is reading this thermometer as though it is the gospel, may be running his stove at too cool an operating temp and thus actually making a condition that could lead to excessive creosote formation in his chimney / flue liner.

While I may not be a professional in the heating / thermodynamics industry, I do have a degree in science (which at least makes me mildly competent) and have been burning wood for my entire life.  Been doing it in open fire places, 2 styles of fisher wood stoves, fisher stove imitators such as the timberline, a modern Jotel, an old style convection stove, a Kalamazoo cookstove, this Englander 30, hell even use a double barrel stove in a cabin I frequent!  Point is I am well aware of the problems associated with overfiring as well as problems from burning a stove too cool.  I know how to operate a stove and that is why I was so concerned by how high this fluegard is reading.  I am using the fluegard to satisfy my inner nerd, I do not need it to burn safely.  I just hope that my results are an isolated anomaly.

I appreciate your offer for a refund, but that is not necessary.  I have now have the fluegard installed about 28 inches above my stove top directly into a 90 degree elbow.  At this level, the temperatures displayed on the fluegard stay within the “normal” range while the stove is also cruising at “normal” surface temperatures (600 to 650 MAX).  I enjoy it’s responsiveness in comparison to external thermometers and it has worked well to show my wife why she needs to be careful leaving the primary air open upon startup as the flue gas temps rise much quicker than the external pipe temps!  But again, my concern is that I believe it reads higher than it ought to at 18 inches above the stove collar.  

Thank you again for listening and considering my concerns,

Any suggestions or criticisms of the results I have gathered would be welcome, 

Best regards,


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## Todd (Feb 1, 2010)

Sounds to me like he thinks your trying to compare your external IR temps to the internal probe and your wondering why it's so much higher? The main question I'd like to know is why they state their probe reads 50% higher than the external temps when in fact supported by everyone here, it reads 100% or double the external temps. Even their painted burn zones coincide with doubling the temps not 50%. Also as the temps climb up over 800 it seems to run away further.


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## pen (Feb 1, 2010)

Todd said:
			
		

> Sounds to me like he thinks your trying to compare your external IR temps to the internal probe and your wondering why it's so much higher? The main question I'd like to know is why they state their probe reads 50% higher than the external temps when in fact supported by everyone here, it reads 100% or double the external temps. Even their painted burn zones coincide with doubling the temps not 50%. Also as the temps climb up over 800 it seems to run away further.



I too think he misunderstood my interpretation.  I am hoping my response makes clearer what my concerns are.  I hope to hear from him again but don't know.

While I am not convinced their product is right, and am surprised that he doubted my IR thermometer even when it agrees with the rutland, I am pleased to see that he even gave me the time of day!  Not many companies are willing to do that.  Now if they would just get their product to read correctly I'd want to buy stock in them!

pen


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## pen (Feb 2, 2010)

Newest Reply:  


Dear Matt,



Youre welcome; we aim to please here at Condar!



It sure looks like the postal service did a number on the first FlueGard we shipped youwow!   They must have driven a postal truck on top of it.  



I cant disagree with your analysis and comparisons and am glad to know you found that positioning the FlueGard a little higher on the pipe helped.  I guess it best that it read a little high because I think most folks tend to burn too hot rather than too cool, so the indication is protecting the high heat burners.



Im glad to know that your friends in-flue thermocouple test was a close match, though I do wonder if the readings would have been even a little closer match had he reversed the positions of the FlueGard and the thermocouple (that is the thermocouple is downstream by 3 or 4 of the FlueGard and would naturally read a little lowerI think).  Whats your friends stove brand and model?



I see one of our really old white surface meters.  How does it compare with the Rutland?



Your results are valuable to us in evaluating field use by consumers.  We appreciate that very much.



Regards,

Tim


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## Highbeam (Feb 2, 2010)

Thank you pen, your efforts are great. 

Thanks also to condar for lying to us and delivering a product meant to trick us into burning our stoves the way you want us to.


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## pen (Feb 2, 2010)

I am surprised that they feel people generally burn too hot.  I would have assumed the opposite.

I am at least impressed that they are addressing my questions / concerns and being candid in their responses.

I too wish that they readings weren't skewed.  But, it is what it is.

pen


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## mikepinto65 (Feb 2, 2010)

Great job pen, thanks for doing this for everyone.


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## fmer55 (Feb 2, 2010)

nice work, i hadev an insert so i don't even use the thermometers but i found this to be one of the most entertaining string si have read........was hooked early then dissapointed by the delay from the 25th to 31st, but back she came, like a fire from the ashes....nice work!


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## Todd (Feb 3, 2010)

Well, I don't know about you guys, but I'm going to loosen it up and adjust mine down 100 degrees to get it closer to Wess's thermocouple readings. I'm pretty convinced Condar's probe reads high after all the evidence. If that don't work I guess it's back to the old external temps.


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## begreen (Feb 3, 2010)

A thermometer isn't doing it's job if it reports with a bias. It's either accurate within the advertised specs or not. If not, return it.


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## BrotherBart (Feb 3, 2010)

Starts to sound like "If any part of the stove is glowing red, you are overfiring." is about as good as any of these overpriced things we have been depending on for many years. And I have more doubts about my IR thermo than I even do about surface thermos. I think it is whack at high temps.


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## Battenkiller (Feb 3, 2010)

BrotherBart said:
			
		

> Starts to sound like "If any part of the stove is glowing red, you are overfiring." is about as good as any of these overpriced things we have been depending on for many years.



Well, that's the system that worked for me until I met everybody here.



> And I have more doubts about my IR thermo than I even do about surface thermos. I think it is whack at high temps.



If you are getting erratic readings as the flue temps are rising, it may be due to turbulence inside the flue moving hot flue gases back and forth.  My IR is about tens times as fast to respond as my magnetic ones and behaves like that during rapid heating.  It seems very stable once the burn stabilizes.  Yours may be different.  I spent a rather princely sum for mine compared to some folks here, but I wanted a "last word" type indicator to use as an accurate reference instrument.


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## Peter B. (Feb 3, 2010)

> *Quote: Condar Advertising*
> 
> When properly installed, the FlueGard accurately reads flue-gas temperatures, with an error margin less than 5%.





> *Quote: Tim Pope - Vice President, Condar*
> 
> You’re welcome; we aim to please here at Condar!
> 
> I can’t disagree with your analysis and comparisons and am glad to know you found that positioning the FlueGard a little higher on the pipe helped.  I guess it best that it read a little high because I think most folks tend to burn too hot rather than too cool, so the indication is protecting the “high heat burners.”







On careful reflection, I have to say I would much prefer accuracy to 'protection'... thanks all the same.

Especially when accuracy is a specific product claim.

But I guess I'm hard to please.





Peter B.





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## pen (Feb 3, 2010)

Peter B. said:
			
		

> On careful reflection, I have to say I would much prefer accuracy to 'protection'... thanks all the same.
> 
> Especially when accuracy is a specific product claim.
> 
> ...



I agree.  

The problem with this probe cannot be fixed by adjusting the face.  The problem is the scale is incorrect.  EVERY test we have tried to come up with shows these probes reading no less than 100 degrees high.  Additionally, The safety zones (even if the probe were reading correctly) require a ridiculously low stove temperature if you are trusting the "normal" range at a level of 18 inches above the flue collar.  In all, I think it is a heavy duty and consistent thermometer, that just needs a redesigned face to reflect ACTUAL values.

From what I have been finding with my stove is that my readings are "reasonable" with the thermometer placed 28 inches up the stove pipe directly into my 90 degree elbow.  At this level on my stove pipe, my "normal" stove operation will fall within the "normal" limits of the thermometer.  Here, the only time I go above their recommended temps is when I first load the stove and am getting the wood charred.

At this level, it pretty consistently reads 50% higher than my stove top.  But obviously not even close to their stated 50% higher than external pipe temps.  Of course, it's still 100-200 degrees off!  It would really be better if there just weren't any numbers on it.  Then I wouldn't feel bad about adjusting the face.

_*In all, for the guy reading this wondering whether or not to buy one, my recommendation would be this:  If you do decide to purchase after reading the information presented here, install it much higher on your stove pipe than 18 inches if you want to be able to burn in the "normal" zone, then just ignore the numbers.*_








pen


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## cmcramer (Feb 3, 2010)

BrotherBart said:
			
		

> Starts to sound like "If any part of the stove is glowing red, you are overfiring." is about as good as any of these overpriced things we have been depending on for many years. And I have more doubts about my IR thermo than I even do about surface thermos. I think it is whack at high temps.



How about the glowing red burn tubes in my Quadrafire 4300?


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## pen (Feb 3, 2010)

cmcramer said:
			
		

> BrotherBart said:
> 
> 
> 
> ...



This is a bit off the original intent of this thread, but, the "glowing red" is referring to external stove parts.  The burn tubes glowing is normal (and good IMO, means your are burning hot and clean)

pen


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## Highbeam (Feb 3, 2010)

I went ahead and ran the flueguard up to 1200 last night for my initial warm up fire. Rather than install the meter in a strange place which will also throw off the lower readings I think it is best to just adjust my setpoints, or mentally moving the colors around on the meter face. We have actual data to show that 1200 measured = 1000 actual, and 500 measured = 400 actual. So simply running the stove between 500 and 1200 will get me what I want. 

Maybe the real fear we should have is that Condar will someday correct their utter failure to perform per the specs and fix the meter. Then we will have people overfiring their stoves based on this thread. 

The condar is a piece of crap meter that doesn't read as it should. Unfortunately it's the best that the hearth industry can do.


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## begreen (Feb 3, 2010)

Based on my older style Condar, I think they can do a lot better. Hopefully this is just a bad batch. If it is reading badly, then time to exercise the warranty and return it for an accurate unit.


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## pen (Feb 3, 2010)

BeGreen said:
			
		

> Based on my older style Condar, I think they can do a lot better. Hopefully this is just a bad batch. If it is reading badly, then time to exercise the warranty and return it for an accurate unit.



Just asked Tim that myself.

My letter



> Out of curiosity, is there any chance that the 2 probes I have received could be part of a bad batch?
> 
> 
> 
> ...


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## firefighterjake (Feb 3, 2010)

Pen: 

Does Condar have any idea that there is a large forum of avid woodstove users . . . users who buy stove accessories . . . who are watching and reading this thread and following Condar's response? I'm not so foolish to think that the hearth.com crowd is so large that Condar would be overly concerned about the bottom line sales . . . but it would be interesting to know what they would think about how interested many of us are in terms of the accuracy of these thermometers.


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## pen (Feb 3, 2010)

I haven't talked with them about hearth.com, but I would think that as easy as this site is to find, that most anyone in the hearth industry should know about it.

Matt


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## karri0n (Feb 3, 2010)

I think directing them to both this and the older thread is a good idea... I know I won't be buying a condar(surface or probe) thermometer any time soon.


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## pen (Feb 3, 2010)

The company has offered to test the damaged probe in their furnace to compare results.  Wes, I'll be shooting you a PM.

Matt


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## Peter B. (Feb 3, 2010)

pen:

If you're going to the trouble, I'd advise you to send them the undamaged probe too... or Condar may want to conveniently blame the inaccuracy on the (original) shipping damage.

Of course, if they should happen to replace the damaged one with an ACCURATE one...

(I'd consider sending mine in as well, but don't want to cloud the issue just now.)

Peter B.

--

By the way, I agree with others who've suggested it - I think Condar should be made aware of this thread and the original "Is This Flue Probe..." thread.

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## Peter B. (Feb 3, 2010)

For those who may think the threads related to Condar probes are overblown, too strident, slightly hysterical or unfair to Condar, consider again that Condar has made a flat claim of accuracy within 5% of the actual flue gas temperature for their probes.

A user who believes the claim may well operate his/her stove in an unsafe fashion.

Once again, quoting Condar's own advertising:

"A woodstove without a thermometer is like a car without a speedometer."

I contend that operating a stove with a wildly inaccurate thermometer is unsafe, just as driving a car with a wildly inaccurate speedometer is unsafe.

Peter B.

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## pen (Feb 3, 2010)

Peter B. said:
			
		

> By the way, I agree with others who've suggested it - I think Condar should be made aware of this thread and the original "Is This Flue Probe..." thread.
> 
> -----



I will bring it up in our next correspondence.

pen


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## Battenkiller (Feb 4, 2010)

Peter B. said:
			
		

> Once again, quoting Condar's own advertising:
> 
> "A woodstove without a thermometer is like a car without a speedometer."




I wonder if these guys are taking a page from the Toyota playbook.  I can just see it...

"A car without a smoothly operating gas pedal is like..."


Maybe Condar will offer to fix them all with a shim?   :roll:


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## njburner (Feb 4, 2010)

Meh. I bought one of these probes just before the original thread was started. Having seen the original thread, I decided to wait on installing it. 

The Condar response to date is less than impressive. So far, nothing in their replies makes me disagree with the consensus on this forum, i.e., the readings on the dials are hundreds of degrees wrong, which could be dangerously misleading.

Before I send my probe unopened back to Condar, does anyone want it for further testing? It's still in the packaging, untouched. PM me before the weekend if you do.


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## jzinckgra (Feb 4, 2010)

As a novice woodstove guy (1st year burning) I have the Flugard probe 18" above the stove and have a straight shot out through the roof. I 'cruise' according to the thermometer at between 450-600F. Does this mean I've been burning at ~100-200F lower? Heck, a couple times I got the probe up to 1100F and got somewhat concerned that I might ignite some creosote in the chimney and quickly closed off the primary. Maybe that temp was actually ok for longterm burning? Being a novice I'm curious if I've been burning too cool all winter long.


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## pen (Feb 4, 2010)

jzinckgra said:
			
		

> As a novice woodstove guy (1st year burning) I have the Flugard probe 18" above the stove and have a straight shot out through the roof. I 'cruise' according to the thermometer at between 450-600F. Does this mean I've been burning at ~100-200F lower? Heck, a couple times I got the probe up to 1100F and got somewhat concerned that I might ignite some creosote in the chimney and quickly closed off the primary. Maybe that temp was actually ok for longterm burning? Being a novice I'm curious if I've been burning too cool all winter long.



That's pretty much exactly my concern as well.  Many people new to doing this rely on these tools.  That is why I and the many others here have persued this so.  We want to make sure that we really can trust these tools as advertised.  

I'd say if I were you, I'd also have a stove top thermometer to verify that you are running your stove warm enough.  

I think by using multiple sources of information (a stove top thermometer, a stove pipe thermometer, and your own good sense) gives you the best results.

Maybe it really is just a "bad" batch and mine is reading higher than others.  But I know in my setup, with the probe 18 inches up the flue I am only running a stove top of about 450 degrees (barely going) and have a flue reading that is just entering the "too hot" zone of about 1000 degrees.  


pen


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## Todd (Feb 4, 2010)

Another thing to consider is Wes999 did the test on single wall pipe and I'm willing to bet temps are 100 degrees lower on double wall pipe because the cooler external temps. Even though Condar states their probe is good on single or double wall there is a difference in temps.

I adjusted mine down about 100 degrees so at room temp it's right at 0 or the line between brown and yellow. Now it's more inline with wes999 thermocouple and is exactly double my external temps except when it goes up over 1000, then it seems to run away.


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## jzinckgra (Feb 4, 2010)

pen said:
			
		

> jzinckgra said:
> 
> 
> 
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I've got the Condor magnetic on the side and that will usually read ~300-350F.  I can't put it on the top since I have a blower baffle that doesn't allow direct contact of stove top to firebox.


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## firefighterjake (Feb 4, 2010)

I would like to see if there are any differences on double wall pipe in terms of the accuracy since it seems to me that this is where most folks with probe style thermometers would tend to use this vs. going with the simpler and less expensive magnetic style thermometer which could be used on single wall pipe.

My own take . . . I still tend to view my thermometers as only a rough guide . . . and when running my stove tend to keep the temps as close to being in the Goldilocks Zone as possible . . . preferring to keep the temps about halfway in the "just right" zone . . . as I have always figured that the temps could easily be running a bit higher or a bit lower . . . and so far, based on the fact that I have not overfired my stove or chimney . . . and I have not had an excessive amount of creosote I have to say the thermometer is working for me.

That said . . . if a company comes right out and says my product is X degrees accurate . . . when in fact tests show it is not accurate . . . well I have a hard time supporting this product if it is not what it promises and it fails to deliver on that promise . . . and so I continue to follow this thread and Condar's response.


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## Highbeam (Feb 4, 2010)

"But I know in my setup, with the probe 18 inches up the flue I am only running a stove top of about 450 degrees (barely going) and have a flue reading that is just entering the “too hot” zone of about 1000 degrees."

Remember that you can't assume anything based on flue gas temp other than how hot the flue gas is. Your stove's temp is not dependent or directly related to flue temp and we should all have a stove thermometer first, and a flue gas temp meter second. For example, I can have my condar reading 1000 in 15 minutes from a cold start and the stove temp is barely registering on the stove's surface temp meter.

I've been much happier with my new routine of starting a new fire and letting the flue gasses run to a "condar" 1200 and then backing off the primary air to cruise level. It's much harder to snuff the fire when the first burn is that hot and that hot first burn does a great job of burning off any junk from the glass.


----------



## jzinckgra (Feb 4, 2010)

So if my glass is staying clean, can I assume I am burning and the right temp and minimizing creosote?


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## mikepinto65 (Feb 4, 2010)

Highbeam said:
			
		

> "But I know in my setup, with the probe 18 inches up the flue I am only running a stove top of about 450 degrees (barely going) and have a flue reading that is just entering the “too hot” zone of about 1000 degrees."
> 
> Remember that you can't assume anything based on flue gas temp other than how hot the flue gas is. Your stove's temp is not dependent or directly related to flue temp and we should all have a stove thermometer first, and a flue gas temp meter second. For example, I can have my condar reading 1000 in 15 minutes from a cold start and the stove temp is barely registering on the stove's surface temp meter.
> 
> I've been much happier with my new routine of starting a new fire and letting the flue gasses run to a "condar" 1200 and then backing off the primary air to cruise level. It's much harder to snuff the fire when the first burn is that hot and that hot first burn does a great job of burning off any junk from the glass.



+1 Im with you on this one Highbeam


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## Troutchaser (Feb 4, 2010)

Was it this thread that we discussed the end of the probe being placed in the middle of the flue?  This is what Condar states you should do and so I pulled mine out of DW pipe about two inches.  When I did this, there was a noticeable decline in temp.  Approx.
100deg. on a steady 600.

Curious if everyone runs with it flush to the pipe.


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## JoeyD (Feb 5, 2010)

Troutchaser said:
			
		

> Was it this thread that we discussed the end of the probe being placed in the middle of the flue? This is what Condar states you should do and so I pulled mine out of DW pipe about two inches. When I did this, there was a noticeable decline in temp. Approx.
> 100deg. on a steady 600.
> 
> Curious if everyone runs with it flush to the pipe.



I just pulled mine out about an inch and I'm going to see if it makes a difference. It seems almost impossible to keep my stove within specs which Napoleon says are 250-450 flue temp. Right now my stove seems to like 550 to 600 with my condar.


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## Highbeam (Feb 5, 2010)

Trout: You are doing much more than pulling the probe tip to the middle of the flue. You are also pulling the bimettalic coil inches from teh heat source where it can be influenced by room air. The design of this meter depends on it being a particular distance from the pipe. Cut the tip of the probe off to hit the center of the flue if you choose. You must run it flush to the pipe, especially with double wall. 

Joey: Many stove manufacturers assume that your "flue temp" is the temp you get when you stick a magnetic surface meter onto the flue pipe. So you can double the Napolean temps to get flue gas temps of 500 to 900 which falls right in the condar recommended operating range.


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## Troutchaser (Feb 5, 2010)

Thanks highbeam.
I can really just cut the thing off and not screw it up (any more than it might already be screwed up from factory)?


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## Todd (Feb 5, 2010)

Troutchaser said:
			
		

> Thanks highbeam.
> I can really just cut the thing off and not screw it up (any more than it might already be screwed up from factory)?



I cut mine but I don't know if it made any difference in temps.


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## Highbeam (Feb 5, 2010)

If Todd hadn't already made the cut then I would worry about the probe being full of fluid or something fancy but apparently the probe is only a steel rod meant to conduct heat to the coil. I don't plan to cut mine. I have determined that it doesn't really matter what the actual temperature indication reads so long as I know the temps on the factory condar which correspond to 400 and 1000 which thanks to the thermocouple work provided on this site we do know these points as 500 and 1200 degrees "condar". Yes I invented the condar units, not celsius or F. We all can agree that the basic meter design is dependable and rugged with repeatable performance. I don't want to loose the repeatable performance by cutting or modifying it.

What's the saying?.... It's precise but not accurate.


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## pen (Feb 26, 2010)

Here is the response from Tim



> Yes, I did receive it and have done multiple temp tests with it through last Friday.
> 
> 
> 
> ...




In general, this means that according to Tim, the reason Wes and I are having high readings are because of the high ambient temps in the area of our stove.  

Additionally, when I had the probe installed 18 inches up from my stove top, I had to run my stove top at about 450 during a "cruise" (ignoring hotter than normal startup conditions) to maintain temps in the normal range on this thermometer.  This is far colder than I normally run my stove top.  At these temps, the stove is in suffocation mode IMO and some visible smoke is seen from the chimney.

My probe gives me temperature readings that are "believable" at a height of 28 inches above my stove top.  In other words, a normal burn where my stove may cruise at 600 to 650 stove top reads at or below their 900 degree mark on the probe.  My question is, are the more reasonable readings the result of a cooler ambient location or the result of truly cooler flue temps?  

My thoughts:

1. In all, I am very happy with the performance of my probe now that I have it installed 28 inches above my stove top.  
2. I disagree with the idea that I am running my stove too hard and feel that their estimates are too conservative.  
3. Essentially, I think that the directions on the package are misleading for installation.
4. I feel that the claim on the package for the probe reading roughly 50% higher than single wall pipe values is bunk.  Rather, at each location I consistently get values that read 3x higher.
5. If single wall surface pipe temps are so inconsistent, how can ANY brand magnetic stove pipe thermometer have any value?


I have shared these thoughts with Tim as well, I will keep everyone posted of any response. 

pen


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## Pagey (Feb 26, 2010)

Thanks for the follow through, Pen.  This has been a most interesting discussion to follow.


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## Todd (Feb 26, 2010)

Thanks for the update Pen. I don't really see how their little machine can simulate the differences in readings of single wall verses double wall. There is no way their probe is accurate at higher temps in single wall with all that radiant heat coming off the pipe.


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## pen (Feb 26, 2010)

Todd said:
			
		

> Thanks for the update Pen. I don't really see how their little machine can simulate the differences in readings of single wall verses double wall. There is no way their probe is accurate at higher temps in single wall with all that radiant heat coming off the pipe.



My thoughts exactly, I asked how about how the machine takes that variable into account in my most recent email 

in fact, here is my response:



> Thank you so much for getting back to me.
> 
> I can't argue with your test and the probes accuracy for that furnace.  My only question is how close to true "in the field" conditions it can be?  For example, do the outer walls of the the furnace where the probe face is mounted also get as warm as it would being against single wall pipe and 18 inches above a stove top?
> 
> ...



pen


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## Battenkiller (Feb 26, 2010)

> I had the occasion to talk with a couple of woodstove OEM’s about temp readings and asked them about flue-gas temps and whether the use of an IR meter is accurate when measuring the surface of the flue pipe; they said absolutely not... even single-wall pipe flue-gas must be measured inside.  They testified the gas swirls and you can see different temps depending on where the measurement is being taken



My experience with my IR is that this is true at startup when the fire is sending up big waves of hot gases.  My IR takes a reading every half second, and I can see the temps jump all over the place (but only +/- about 10ºF), even when the red dot is stationary.  At first, I thought my IR was bonkers, but I finally came to the conclusion that this is due to the violent nature of the gases during a hot, open burn conducting the heat through the thin metal almost instantaneously.  Readings taken later on once a stable burn was established seemed very steady.  But then, won't there be _internal_ temperature variations due to the same gas swirls?

Another danger might be that either an IR or a magnetic thermo might give a false negative regarding excessive flue pipe temps in a situation where a buildup of soot and creosote inside the flue pipe is insulating the pipe from the gases inside.  A newbie burning inferior wood and building up massive amounts of creosote might get a false sense of security and run his flue temps up even hotter without knowing he is already in a hazardous situation.  Just a thought.


Given the problems discovered in using the internal thermometers in varying situations, I think a thermocouple probe reading is the only sensible way to measure flue gas temps.  Readings are basically instantaneous and are unaffected by any variance in the ambient environment. There are so many things you can do with the output of these devices as well. Someone here set up a stove temp monitoring device with his (was it Wes, I can't recall), and that would be really helpful to those among us who are basement burners.






			
				pen said:
			
		

> If single wall surface pipe temps are so inconsistent, *how can ANY brand magnetic stove pipe thermometer have any value?*



I surely saw the irony in their statement as well.  However, I feel that these devices are, at best, merely indicators of the current state of your burn.  If you have a single-wall pipe, a magnetic thermo will be close enough in 99% of the cases.  With double-wall pipe, you absolutely need an internal unit.  In an ideal world, get the real temp with a thermocouple probe and a digital readout.


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## WES999 (Feb 27, 2010)

One test that would be interesting would be see what the difference between the Condar probe installed on single wall and double wall. I considered installing the Condar on my Regency upstairs stove ( it has DW pipe) but did not really want to drill a hole in the pipe.
I would guess with the bi-metal spring receiving less heat it may be more accurate.


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## pen (Feb 27, 2010)

And the last reply.  Now that he's getting less specific with answering my questions while still being very cordial, I say the conversation is politely coming to a close.

I'd say this last reply supports Wes's most recent claim: that the single wall's radiant heat is causing the probe to read high.



> Here is our set-up for testing the probe meters.  It is configured so
> that there is some gap between the heat source and coil.  This set-up
> would more closely be like double-wall pipe or for testing catalytic
> combustor probes that insert through the top or side of a woodstove.
> ...



In the end, my opinion is that this probe will work fine for double wall as per instructions, but should be installed higher on the flue pipe for a single wall install.  

I wish they would consider more "real world" testing and perhaps amend their instructions accordingly as I think this probe installed on a single wall pipe 18 inches up from the stove (being read as the gospel) would cause the average operator to run the stove too cool.

pen


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## imacheezhead (Feb 27, 2010)

This may not be totally relevant to this thread but since you are talking about inaccurate temperature probes I'll give it a shot anyway. 

I have a Consolidated Dutchwest that utilizes a condar catalytic temperature probe that I just replaced.  I'm looking at this thing as it came out of the box and according to it my room temperature was 350 deg.!  I installed it and it said my combustor temp. would get up to 1600 deg.  This didn't seem right to me so when the fire started to die down I noted the temperature and it said about 800 deg.  I took my digital meat thermometer and stuck the probe in the hole without touching the combustor and it said the temperature was about 400 deg.  That raised my flag a little!  I looked at some pics on the internet of the same probe I have and they also say 350 deg.  I adjusted the probe according to what my meat thermometer said and now the temps seem to be more realistic and my maximum combustor temperature is around 1200 deg.  I noticed that some of the probes have digits below the 400 deg. mark and they show a temp. of about 70.  The one I have starts at 400. 

Am I missing something here or are these probes leaving the factory uncalibrated?

Thanks, Jim


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## WES999 (Feb 27, 2010)

Just a thought, perhaps a washer say 2" or 3" dia.  and a short spacer maybe 3/8" long  installed on the end of the probe to simulate double wall pipe would improve accuracy.

This would shield the by-metal spring from some of the radiated heat from the single wall pipe.

If I would have thought of it earlier I would have tried it. :-S


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## Troutchaser (Feb 27, 2010)

Maybe for SWall pipes the probe could be pulled out an inch from the pipe for a more accurate reading?  Just a thought for all those who already have a hole drilled 18" up from the stove.
I wonder in their little test machine what the air temps are around the face of the probe?


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## Todd (Feb 27, 2010)

WES999 said:
			
		

> Just a thought, perhaps a washer say 2" or 3" dia.  and a short spacer maybe 3/8" long  installed on the end of the probe to simulate double wall pipe would improve accuracy.
> 
> This would shield the by-metal spring from some of the radiated heat from the single wall pipe.
> 
> If I would have thought of it earlier I would have tried it. :-S



I tried that and it didn't seem to make much difference. There's too much radiant heat surrounding the whole area. I think Condar has to recalibrate those probes for single wall.


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## Todd (Feb 27, 2010)

imacheezhead said:
			
		

> This may not be totally relevant to this thread but since you are talking about inaccurate temperature probes I'll give it a shot anyway.
> 
> I have a Consolidated Dutchwest that utilizes a condar catalytic temperature probe that I just replaced. I'm looking at this thing as it came out of the box and according to it my room temperature was 350 deg.! I installed it and it said my combustor temp. would get up to 1600 deg. This didn't seem right to me so when the fire started to die down I noted the temperature and it said about 800 deg. I took my digital meat thermometer and stuck the probe in the hole without touching the combustor and it said the temperature was about 400 deg. That raised my flag a little! I looked at some pics on the internet of the same probe I have and they also say 350 deg. I adjusted the probe according to what my meat thermometer said and now the temps seem to be more realistic and my maximum combustor temperature is around 1200 deg. I noticed that some of the probes have digits below the 400 deg. mark and they show a temp. of about 70. The one I have starts at 400.
> 
> ...



I'd send it back and get a new one. It shouldn't read 350 at room temp and you don't know if your adjustment is accurate.


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## pen (Feb 27, 2010)

Todd said:
			
		

> imacheezhead said:
> 
> 
> 
> ...



go to the website, contact a person there and I am sure they will treat you well. 

pen


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## pen (Feb 27, 2010)

WES999 said:
			
		

> Just a thought, perhaps a washer say 2" or 3" dia.  and a short spacer maybe 3/8" long  installed on the end of the probe to simulate double wall pipe would improve accuracy.
> 
> This would shield the by-metal spring from some of the radiated heat from the single wall pipe.
> 
> If I would have thought of it earlier I would have tried it. :-S



I tried this and it made no difference.


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## Peter B. (Feb 27, 2010)

I've simply gone back to using my 20 year old Condar probe, which I'm convinced provides more accurate temp readings than the three newer Condars I bought last year.

--

It may be a meaningless side note, but in the oven test I made (which mainly proved that oven tests give bogus results from probes), I noted that at three different temperatures, all of the probes gave consistent readings as factors of the actual stove temp... suggesting that they were responding uniformly.

However, the old probe factor was about 2.6x the actual temp, while the new probes read about 3.7x.

Interestingly, a fourth new Condar probe (a cat probe with 2" stem) read consistently LOWER than the old probe... for a factor of 2.4.  (All the other probes have 4" stems.)

Needless to say, I haven't got much faith in any of the new probes.  I should have returned them all, but I guess I just got lazy.

I'll sell them cheap, if anyone's interested.

Peter B.

-----


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## Peter B. (Feb 27, 2010)

Incidentally, I thought I might explain how/why I ended up with so many thermometers...

Originally, I ordered a new FlueGard and the 2" cat probe - the former to replace the 20 year old probe, the latter to monitor catalyst temp continuously... which I'd never done before.

I discovered the wide temperature discrepancy between the new FlueGard and the old probe right away, wrote Condar and asked for an exchange, which they agreed to, and I requested two of the 4" cat probes so I might AT LEAST have two identical thermometers that actually agreed.

The two cat probes more or less agreed with one another... and the new FlueGard.  But the 2" cat probe came close to agreeing with the old probe, so I really didn't know what to think.  The range of difference (in actual use) between the two groups of probes was on the order of 100*-300* at differing stove temperatures.

In any event, I never got around to returning any of them... so I'm a bit 'overstocked' with thermometers of questionable accuracy.

Peter B.

-----


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## pen (Feb 27, 2010)

Peter B. said:
			
		

> so I'm a bit 'overstocked' with thermometers of questionable accuracy.
> 
> Peter B.
> 
> -----



That questionable accuracy is what discourages me.  From everything I have done (and you and wes as well) we seem to be finding that these are very consistent.  However, I am afraid that they only accurate in a special set of circumstances.

I trust that the probe I sent Tim truly did respond as he stated in his furnace.  I have no doubts that under certain conditions that his probe would read accurately.  

My point is this:  

1.  Installed as the directions on the package state, this thermometer does not perform as stated and will not read accurately for single wall pipe. 
2.  I think more testing by condar needs to be done using real wood stoves, and not a furnace.  
3.  I think that the package information / directions need to be changed to reflect the differences we have all noted here so that the product can be used as a true gauge of a user's burn quality.


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## Peter B. (Feb 27, 2010)

A few more comparative observations...

As mentioned, I've used the 'same old' Condar probe now for twenty years.  I learned early on that the flue probe - located about 18 linear inches above the internal catalyst - must read a _solid_ 400* or more before the catalyst will light off.  I've used the same guideline successfully for all those years.

Most literature suggests that catalyst light off occurs at about 600* (stove internal temp, measured at the catalyst 'intake' point).

My cat slides forward and back to achieve bypass.  Using 400* flue temp on the old probe as my most reliable guide, the new 4" cat probe placed in the exhaust flow (at the point where the catalyst sits in the 'on' position), must read 1000* or better before the catalyst will light off.  This corresponds to 400* or better on the flue probe.

If the cat actually lights at 600*, that means the new cat probe is off by a full 400*.

And if I trusted the cat probe only, I might be trying to engage the cat at a nominal 600* thermometer temp... some 300*-400* below that actually required for light off.

The new FlueGard (in place of the old probe) would have to read 550*-600* at 18" ABOVE the catalyst to achieve reliable cat light off.

I don't know what Condar has changed in their probe manufacturing 'recipe' in twenty years, but as near as I can tell they made a rock solid reliable thermometer 'back when'... and they're not doing so now.

Peter B.

-----


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## pen (Feb 27, 2010)

Peter B. said:
			
		

> I don't know what Condar has changed in their probe manufacturing 'recipe' in twenty years, but as near as I can tell they made a rock solid reliable thermometer 'back when'... and they're not doing so now.
> 
> Peter B.
> 
> -----



If your old one is the 3-19, here is what I was told by Tim:



> The 3-19 bill of materials was identical to the 3-39, except for the graphics and enameled dial face, that does not affect the reading.



seems odd doesn't it?

pen


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## Peter B. (Feb 27, 2010)

pen said:
			
		

> Peter B. said:
> 
> 
> 
> ...



I'm pretty sure my old one is a 3-19... but something else MUST have changed.

It's very easy to document the difference between the two directly.

Leaving out ALL other considerations, the two thermometers read between 150*-250* apart switched back and forth between the same locations and left for several (15) minutes to stabilize... this on a fairly constant fire.

I specifically requested another 3-19 when I wrote to Condar for an exchange.  They said the 3-39 had replaced it.

I wonder if BeGreen would sell me his old 3-19?  Maybe then I could make some useful relative comparisons of stove internal and flue temps.

Peter B.

-----


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## begreen (Feb 27, 2010)

Right. Out of my cold dead hands...  :coolgrin: 

I would consider sending it to Wes999 for a thermocouple test. The older 3-19 seems to read a lot lower. It would be nice to see where it falls in a side by side test next to the 3-39.


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## Peter B. (Feb 27, 2010)

BeGreen said:
			
		

> Right. Out of my cold dead hands...  :coolgrin:



Have it your way... I'm hopping the next freight to come and pick it up.

And I'll bring a pry bar.

Peter B.

-----


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## imacheezhead (Feb 27, 2010)

I’d send it back and get a new one. It shouldn’t read 350 at room temp and you don’t know if your adjustment is accurate. 
I do believe my adjustment is accurate.  The meat thermometer is accurate to within 2 deg. according to my highly scientific boiling water test.  What is the highest cat temperature I can expect?   Right now I seem to be topping out at 1200 deg. burning oak. My cat seems to be in good shape yet and it's only in its 2nd heating season.

Jim


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## woodjack (Dec 12, 2010)

This has been a fascinating thread (Parts I and II). Pen, and everyone else that contributed, thanks much.

However, the final analysis left me a baffled.
Pen, considering all the erroneous temperature readings, I'm surprised that you believe the Condor probe thermometer would work properly for a double-walled flue ("In the end, my opinion is that this probe will work fine for double wall as per instructions."). It almost seems to have your endorsement. Am I misinterpreting your conclusion?


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## pen (Dec 12, 2010)

woodjack said:
			
		

> This has been a fascinating thread (Parts I and II). Pen, and everyone else that contributed, thanks much.
> 
> However, the final analysis left me a baffled.
> Pen, considering all the erroneous temperature readings, I'm surprised that you believe the Condor probe thermometer would work properly for a double-walled flue ("In the end, my opinion is that this probe will work fine for double wall as per instructions."). It almost seems to have your endorsement. Am I misinterpreting your conclusion?



Good question.  After running this again this season, and after all the testing last season I'll say this:  For the right or for the wrong, it's a consistent thermometer.

That means, it may read consistently high, but I do trust that it's always giving me the same "value" for a equivalent burn.  What I think is junk is the numbers and indicator recommendations.  I really wish they just sold a blank one and i'd mark it myself w/ high burn / low burn.  

For me, I couldn't get these burn sections (too cool, normal, too hot) to be even close to being correct until I moved the thermometer almost 30 inches above the stove.  

I think that part of the problem is that the thermometer is taking on a ton of radiant heat from the single walled pipe.  It still reads consistently, just not accurately.

I think that w/ the protection of a double wall stove pipe, It has a better chance at being accurate and precise (consistent) at the recommended 18 inches above the stove.

However, on single wall pipe, I simply believe them recommending it to be only 18 inches up the pipe is giving readings that are still consistent, but not accurate, and I worry that people are burning their stove too cool as a result.  

Tim tested my thermometer and WES did.  I believe that Wes's test was most accurate to a "real world" or "field" setting.  I firmly believe that Tim wouldn't lie to me and when he retested my thermometer in his special furnace, that it did test to within spec.  My argument is that his thermocycler doesn't duplicate "in the home" conditions and that they should change their testing back to something more like what Wes did.

pen


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## LAndrim (Jan 31, 2011)

Condar confusion!

Thanks to everyone for doing all this extensive testing! As a newbie, this is why I love this forum, it is always a learning experience based on good solid field-tested results from generous people who care about the "art of the stove."

That said, I am so thoroughly confused, now,  and a bit concerned.  As someone new to wood burning, I thought that buying a probe thermometer for my one month old Lennox Canyon ST310 would be a fairly accurate way to see if I am safely burning. I now see that this is not the case.

When anyone purchases a product, we expect to get what we pay for; what I'm finding from this extensive thread is, this is not always so.

In my DW pipe, at 18" up ( as Condair recommends) I get  a  read from 400 to 600 when I'm in a fairly heavy-duty burn cycle.  I've posted in this forum about my chimney cap being totally grunged up at only 4 weeks of burning seasoned hardwoods, and now I'm thinking that I've been burning too low because the thermometer is way off.  I have a 6" DW pipe ,and I don't think the thermometer is in the center, even though I folowed Condar's drilling guidelines.

I don't want to burn too low since what I've read is,  this is a potentially dangerous  creosote situation. So what is the resolution on the Condar?  Should I scrape it and get a Rutland for stove top only? I'm now gun shy and rather concerned. Thanks much!


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## pen (Jan 31, 2011)

Most are finding that they read too high which is the opposite of what you are seeing.  

The biggest problem is with the probe thermometers on single wall pipe.  Double wall pipe has much lower surface temperatures and therefore I believe it will have a more accurate reading.  As such, on a fresh load you should be seeing 800 on that probe no problem.

More results will come in this week as BeGreen is sending me a vintage condar probe to use as comparison to my new probe since I already have 2 holes in my flue for probe placement.

pen


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## LAndrim (Jan 31, 2011)

Getting 800 on fresh load of splits is something I have not seen yet.  Do I have a defective Condar or is the probe not "centered" in a 6" pipe...should I pull it out a bit?


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## pen (Jan 31, 2011)

Jamison said:
			
		

> Getting 800 on fresh load of splits is something I have not seen yet.  Do I have a defective Condar or is the probe not "centered" in a 6" pipe...should I pull it out a bit?



if it were defective when at room temp the needle would be reading some value that wouldn't look right.

pen


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## begreen (Jan 31, 2011)

Jamison said:
			
		

> Condar confusion!
> 
> Thanks to everyone for doing all this extensive testing! As a newbie, this is why I love this forum, it is always a learning experience based on good solid field-tested results from generous people who care about the "art of the stove."
> 
> ...



There could be other reasons for creosote build up. Can you describe the complete flue setup from stove to cap including elbows and tees? A stove top thermometer can be helpful. I like both, but would opt for the stove top first if there was only one option.


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## Todd (Jan 31, 2011)

Well since this thread popped up again I might as well tell anyone that may be interested, I went out and purchased an SBI probe that is similar to the Condar. I almost drilled another hole in my pipe to get a side by side comparison for you all but decided against it. The SBI is cruising at 600-700 internal with an external of 250-300. My Condar is reading about 50-100 higher in that same external range. The Condar also seems quicker to run away on a fresh reload once temps get up over 800. Not a huge difference and I'm sure these flue temps would be less in a double wall pipe than my single wall. SBI instructions state this thermometer is for double wall pipe unlike Condar who says it's good for both.


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## LAndrim (Jan 31, 2011)

Hi BeGreen,

My set up is pretty simple:

1. Lennox Country ST310 
2. Six inch  4 ft double wall pipe/ top vented into
3. cathedral ceiling support box, then piping thru my roof and
4. eight feet Temp Guard chimney piping with cap 

It's a straight shot, no elbows.

I'm using seasoned hardwoods, start with a small hot fire, then load maybe 6 splits or so, giving them full air flow for about 15 minutes, then will slowly cut back on air.

What am I doing that I can't get higher temps on the Condar probe?  I've got 6" double pipe, and it does not seem to be sitting flush to the pipe...should I cut it? And why the creosote? Thanks much!


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## woodjack (Jan 31, 2011)

Todd, I'm confused. Do you think the thermometers are accurate or not? I was going to get a probe thermometer for my double wall pipe, but this thread put a damper on things.

What's the bottom line on probe thermometers and which brand is best?


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## 3fordasho (Jan 31, 2011)

Just to add to the Condor confusion-  my experience was the opposite, instead of reading too high, my condor probe thermometer seldom got above 200-300F.  I concluded it was due to my installation in a telescoping section of double wall connector pipe.  Mine was installed in the "overlap" section of telescoping connector pipe there is actually 4 layers of sheet metal... leading to a extremely low reading.   I've since moved to Tel-tru probe thermometers that have a reading range of 200-1000F.  The coiled element is in the flow of flue gasses (inside the stainless probe tip).  I've found these to be accurate and reliable as long as I don't exceed the 1000F limit.  These have a quick reaction time, at least compared to what I saw with the condor probe.  I use one of their replacements for the thermometer in a "big green egg", can be had for ~$20.
http://www.teltru.com/s-136-big-green-egg-grill-dome-kamado-replacement-thermometer.aspx


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## Todd (Jan 31, 2011)

woodjack said:
			
		

> Todd, I'm confused. Do you think the thermometers are accurate or not? I was going to get a probe thermometer for my double wall pipe, but this thread put a damper on things.
> 
> What's the bottom line on probe thermometers and which brand is best?



I don't think probe thermometers are accurate "number" wise according to Wes999's tests with his thermocouple, but in my opinion they are close enough and consistant enough to be used as a valuable tool. I also think they are better designed for double wall because the radiant heat off single wall effects the temps.

Personally I like this SBI probe better. The color of the face plate makes it easier to see from a distance and it seems to read a bit lower than the Condar and not run away at higher temps in the beginning of the burn cycle.


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## woodjack (Jan 31, 2011)

Todd, thanks for your reply. And again, thanks for all the info, testing, and analysis. This has been one of the most interesting threads in the entire forum.


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## begreen (Jan 31, 2011)

Looks like I am one of the lucky ones that gets pretty consistent and usable readings from the flue probe thermometer on double-wall pipe. It might just be the flue design. Straight-up piping may be a stronger influence on readings here than realized. FWIW, I like the smaller, more discrete style thermometer. I only look at them when close to the stove. From a distance I let the fire and ecofan be my guide. 

Todd is there any indication of country of origin for the Condar or SBI products? They look remarkably similar except for the dial paint.


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## Todd (Jan 31, 2011)

BeGreen said:
			
		

> Looks like I am one of the lucky ones that gets pretty consistent and usable readings from the flue probe thermometer on double-wall pipe. It might just be the flue design. Straight-up piping may be a stronger influence on readings here than realized. FWIW, I like the smaller, more discrete style thermometer. I only look at them when close to the stove. From a distance I let the fire and ecofan be my guide.
> 
> Todd is there any indication of country of origin for the Condar or SBI products? They look remarkably similar except for the dial paint.



SBI probe is Made in China, but SBI is out of Quebec. I think they build Osburn and Drolet stoves?

Condar says built in the USA.


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## begreen (Jan 31, 2011)

I just had a nice chat with Tel-Tru. They are looking at the stove market. I asked if they were considering making thermometers with a higher temperature range, more appropriate for flues. The response was that they don't make any bi-metal thermometers for high temp ranges because the spring gets too brittle, affecting its accuracy. "All thermometers with a bi-metal sensor including the surface type thermometer need to be limited to temperatures under 800F because the high heat will harden the coil and it will become less accurate and eventually stop working." 

Perhaps this relates to the inaccuracy seen at the high end with these units?


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## pen (Jan 31, 2011)

Hmm, that is interesting.  With these tel-tru units, is the bimetallic coil visible on the back?

pen


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## pen (Jan 31, 2011)

Now that I think of it....

The probe reading 800 be experiencing much cooler temps (for the body of the unit itself) than the surface thermometer would.

A surface thermometer is actually living in the 800 degree environment if that's what it is reading.  A probe thermometer is just interpreting 800 degrees.  

I'd ask the guy about that and see what he says.

pen


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## begreen (Jan 31, 2011)

I don't know for sure because we still have our trusty, 30 yr old glass dial, Sandhill. From the drawings, I would guess it is open on the surface magnetic units. But it appears to be enclosed in their probe units. Not sure about the BGE units either.

http://www.teltru.com/s-54-dual-magnet-thermometers.aspx
http://www.teltru.com/s-14-back-connected-small.aspx

BGE: http://www.teltru.com/p-272-big-gre...ent-thermometer-lt225r-2001000-degrees-f.aspx


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## Todd (Feb 1, 2011)

3fordasho said:
			
		

> Just to add to the Condor confusion- my experience was the opposite, instead of reading too high, my condor probe thermometer seldom got above 200-300F. I concluded it was due to my installation in a telescoping section of double wall connector pipe. Mine was installed in the "overlap" section of telescoping connector pipe there is actually 4 layers of sheet metal... leading to a extremely low reading. I've since moved to Tel-tru probe thermometers that have a reading range of 200-1000F. The coiled element is in the flow of flue gasses (inside the stainless probe tip). I've found these to be accurate and reliable as long as I don't exceed the 1000F limit. These have a quick reaction time, at least compared to what I saw with the condor probe. I use one of their replacements for the thermometer in a "big green egg", can be had for ~$20.
> http://www.teltru.com/s-136-big-green-egg-grill-dome-kamado-replacement-thermometer.aspx



I wish that thermometer had a little higher range. I can see pegging it pretty easily if your not careful. What kind of temps do you generally see with it?


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## 3fordasho (Feb 1, 2011)

Todd said:
			
		

> 3fordasho said:
> 
> 
> 
> ...




Two fireviews with different flue set-ups and different temp probe locations due to the flue differences.  On start up or reload (bypass open) I try to keep flue temps 500-600F.  In cruise mode (load of wood/cat engaged) one stove will run 300-400F, the other runs 400-500F (flue temp, not stove top).  I've only pegged the tel-tru once or twice when I forgot to shut down/watch the temps for a few/5 minutes and yes it can happen pretty easy but this is the time you can't let yourself get distracted or really even leave the stove room as I seen reloads go from 400 to 1000F+ in minutes.  I have not pegged either one this season or last so I must be keeping a closer watch on things.  One tel-tru did read low after the over temp incident.  Most models can be recalibrated.


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## begreen (Feb 1, 2011)

Dasho, what is the flue setup? Straight up or with elbows?


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## Todd (Feb 1, 2011)

3fordasho said:
			
		

> Todd said:
> 
> 
> 
> ...



Wow, those temps seem low but if you figure flue temps are 50% higher than external single wall temps like Condar states it would be right in line with mine. I guess I might have to try another thermometer.


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## 3fordasho (Feb 1, 2011)

BeGreen said:
			
		

> Dasho, what is the flue setup? Straight up or with elbows?



Both stoves use Supervent products as sold at Menards.  All connector sections are double wall, the class A stuff is the double wall stainless with the insulation between.

Stove A (first installed) has a 90 elbow right on the back of the stove, an ~3' vertical run of double wall connector pipe(tel-tru is installed in this section, about 24-30" above the stove) to a 45 elbow, 1' straight to another 45 elbow that ceiling connects to 15' of class A.
Aproximately 4-5' of the class A is in attic space, the rest exposed. This is the stove that runs 300-400F flue temps at cruise.

Stove B has a horizontal run of adjustable length double wall connector pipe (~18") that goes straight out the back of the stove to a section of class A that comes thru a wall thimble.  Next is a class A tee, then a vertical class A run of ~ 21' encased in an insulated chase with the top 3' exposed.   In this set up my tel-tru flue themometer is in the horizontal adjustable length section of connector pipe, about 16" from the back of the stove.  This one runs 400-500F flue temps at cruise.


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## begreen (Feb 1, 2011)

Thanks. You are seeing higher temps in the flue with the same stove when the flue gases are slowed down by a 90deg turn. That seems logical and may help explain why my temps are so consistently reasonable with a straight-up pipe.


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