# Is this Flue Temp Probe Full of "It"?



## pen (Jan 21, 2010)

Just opened the box on a new flue temp probe and installed.  







Is this sort of results what you guys get?  As you can see, my old rutland is very accurate with my infrared thermometer (the low was recorded in the pic as 288, MAX of 315, rutland is reading 300, not bad IMO)  But the new probe thermometer is at the top of the safe zone at 900!?!

The stove has been cruising for about an hour w/ the air turned down.  Stove top is about 650.  

Is this normal?  I figured since the rutland and the new probe are both 18 inches up, that reading low on the rutland would also read on the low side for the flue probe.  

What sort of readings do you guys get?  

I think the next step is to put the new probe thermometer in the oven to check it's accuracy.  I hope that the paint on the face can withstand being IN 500 degrees.

Thoughts?

pen


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## cmonSTART (Jan 21, 2010)

Your probe thermometer measures the temperature of the gasses inside the flue.  Your rutland surface thermometer measures surface temp of the pipe.  The surface temperature is just shy of half of the flue temp usually.


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## pen (Jan 21, 2010)

cmonSTART said:
			
		

> Your probe thermometer measures the temperature of the gasses inside the flue.  Your rutland surface thermometer measures surface temp of the pipe.  The surface temperature is just shy of half of the flue temp usually.



I am well aware of that.

Point is, they are BOTH flue thermometers.  I would have thought that if the external one was reading towards the cool side of the operating temp so shouldn't the probe. 

If I were to get up to 500 on the rutland (which would be safe according to that) I'd be absolutely well above the safe operating specs on the probe thermometer. 

I was expecting more along the lines of the rutland reading 300 and the flue probe 600.  

pen


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## cmonSTART (Jan 21, 2010)

Ok, I see what you're saying.  That does seem a bit fishy, but remember the "safe zones" can be pretty subjective.


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## ckdeuce (Jan 22, 2010)

Pen,

For what it's worth I have the same probe T and I get in the 800-1000 range when my stove is crusing.  I would not worry.

Chris


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## Battenkiller (Jan 22, 2010)

ckdeuce said:
			
		

> Pen,
> 
> For what it's worth I have the same probe T and I get in the 800-1000 range when my stove is crusing.  I would not worry.
> 
> Chris



That may be good advice to not worry since his old Rutland says he's good to go, but I guess I'm thinking what's the point of the probe if it's not accurate.  The more accurate external and IR thermos tell you all you need to know.


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## Todd (Jan 22, 2010)

Single wall pipe right? I brought this up in another thread before, but those Condar probes in my opinion are better for double walled pipe. There is too much heat coming off single wall pipe that boosts the reading compared to double wall pipe. These Condar Probe thermometers are calibrated to read the internal temps and they still have the spring loaded dial on the outside which is effected by the radiant temp of the pipe. DW pipe has a lower outside temp so you will get a lower temp. If you hold a match under the dial or blow on it you will see what I mean. Mine reads similar to yours a 300 external temp is a 700-800 internal on my Condar probe. I now just go with an external pipe temp.


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## Highbeam (Jan 22, 2010)

Is that pipe double wall? If so then you can just ignore whatever the rutland or the IR reads. I really cant tell from the photo.

If it is single wall then I would expect the rutland to read half of what the condar says. I would also believe that the condar is more accurate than the rutland.

My condar routinely reads 600-800 when the stove is down around 400. I daily bounce to 1000 for clean outs.


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## ckdeuce (Jan 22, 2010)

Todd said:
			
		

> Single wall pipe right? I brought this up in another thread before, but those Condar probes in my opinion are better for double walled pipe. There is too much heat coming off single wall pipe that boosts the reading compared to double wall pipe. These Condar Probe thermometers are calibrated to read the internal temps and they still have the spring loaded dial on the outside which is effected by the radiant temp of the pipe. DW pipe has a lower outside temp so you will get a lower temp. If you hold a match under the dial or blow on it you will see what I mean. Mine reads similar to yours a 300 external temp is a 700-800 internal on my Condar probe.



Yep...  And if you question this, pop that probe in the oven and you will see MAJOR temp difference.  Like Todd states above, the dial section does not like the heat and will throw it off.


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## n6crv (Jan 22, 2010)

Don't try the oven as it will read WAY high. If you put it in the oven the whole thermometer will heat up and it will be off. Mine read about the same as yours at first. What I did was use a infrared thermometer and a mag mount that read real close. Then loosened up the nut on the Condar probe and turned it back to where it reads 2x the outside temp. Seems to be close to reading correct. It does get off the higher the probe temp goes up. Surface temp of 500 will read about 1200 probe.


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## pen (Jan 22, 2010)

it is single wall pipe.


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## pen (Jan 22, 2010)

N6CRV said:
			
		

> Don't try the oven as it will read WAY high. If you put it in the oven the whole thermometer will heat up and it will be off. Mine read about the same as yours at first. What I did was use a infrared thermometer and a mag mount that read real close. Then loosened up the nut on the Condar probe and turned it back to where it reads 2x the outside temp. Seems to be close to reading correct. It does get off the higher the probe temp goes up. Surface temp of 500 will read about 1200 probe.



Just hate having to manually adjust it that far out of range since it seems like it had a reasonable reading at room temp

Seems that they should have corrected for the extra radiant heat for this w/ a shield for single wall pipe.  Perhaps I'll have to make one out of some flashing and mount it between the magnet and the face to see what happens.  

pen


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## pen (Jan 22, 2010)

Cut a "shield" and placed it between the magnet and probe face to see if it made a difference.  Loaded the stove up for bed about an hour ago and ran it just a touch harder (about 675 on stove top) to see the difference.

In all, I can't see where the shield helped.  Perhaps condor is just too conservative (low) with their recommended flue temps?  The rutland has tested accurate to what it is reading time and time again.

view of shield





new readings a little hotter, same result






thoughts?

pen


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## Todd (Jan 22, 2010)

That little shield won't help with all that other exposed pipe around. I tried the same thing but used an oversized washer and it didn't help. I wouldn't worry because your external temps are fine.


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## Battenkiller (Jan 22, 2010)

350º on the external and 1000º on the probe T?  What can that possibly that tell you?  I was gonna buy one, but that photo made my mind up.  I'm gonna order a thermocouple probe for my IR thermo instead.


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## pen (Jan 22, 2010)

Battenkiller said:
			
		

> 350º on the external and 1000º on the probe T?  What can that possibly that tell you?  I was gonna buy one, but that photo made my mind up.  I'm gonna order a thermocouple probe for my IR thermo instead.



I am tending to agree with you.  Basically, I know it's safe so I'll just burn the stove as always and just see what that probe has to say about it.

What a disappointment that it is so terribly off on this single wall pipe.  I haven't noticed others post about this before.

I may also consider plugging this hole and moving it to the other side of the elbow.

pen


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## jebatty (Jan 22, 2010)

I had the Condor probe on single wall pipe and then replaced it with a K-type digital probe. Readings dropped about 125F with the digital probe. I also have a Rutland surface thermometer. On the same flue, simultaneously, the Rutland read about 1/2 of the Condor. I regard both thermometers as giving relative readings and not accurate readings. Another point, the Condor responds quite slowly to temp changes. In other words, on a high burn start, once the Condor probe gets up to the maximum temp, it will drop very slowly even though actual interior flue temp may have dropped a lot. 

On my wood stove, I use the Rutland surface thermometer, about 18" above the top of the stove. My stove purrs at temps of 325-400F surface temp. On my Tarm gasification boiler, I now use the digital probe. The gasifer purrs at 400-475F probe temp, which would be about 200-250F surface temp. The gasifer is rated 4x the btu rating of the stove, and it obviously is much, much more efficient than the wood stove at turning wood into usable heat energy.


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## pen (Jan 22, 2010)

I am consistently reading 3x higher on the condor than on the rutland .  Ran things good at warm at start-up this morning.  400 on the rutland was 1200 on the condor.

I think I am going to move the probe up higher in the flue, to the other side of the elbow.

pen


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## Highbeam (Jan 22, 2010)

I'm thinking it's time for someone to talk to the condar folks. It is a small american company that prides itself in making accurate instruments. I'm thinking that the above pictures would trouble them and perhaps they can offer advice for adjustment. 

We all know that the single wall pipe's outer shell temp should be "about" half of the internal temp. I would expect that the probe meter be accurate over the normal range and if this means that it's wrong at room temp then so be it. 

Do NOT put any of these in the oven and expect to verify their accuracy. These are not oven thermometers.


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## pen (Jan 22, 2010)

email sent including the pictures.

I look forward to their response.  

pen


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## begreen (Jan 22, 2010)

The reading seems wonky. I would expect normal flue gas temp with a probe to be in the 400-600 range. This appears to be confirmed by the Rutland surface thermometer. Flue pipes are not made to be regularly running at above 1000, especially over an extended period of time.


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## pen (Jan 22, 2010)

Highbeam said:
			
		

> We all know that the single wall pipe's outer shell temp should be "about" half of the internal temp. I would expect that the probe meter be accurate over the normal range and if this means that it's wrong at room temp then so be it.



Agreed, however if that is the case, then they need to change the dimensions of their scale that is printed on the face so that it does provide an accurate reading across its full scale.

pen


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## begreen (Jan 22, 2010)

Not agreed. The surface temp is not half the inside temp, at least according to Condar. Condar states that interior temps should be about 50% higher than surface temps. That would mean a 400 °F  surface reading would equal about a 600 °F interior temp.


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## Diabel (Jan 22, 2010)

I do not mean to high jack this thread but my situation is related & as intriguing... (sorry for the fuzzy pic) both read pretty much 600* 

btw I just installed the probe to find this out.....For the past five years I used the surface thermo. placed right on the flue & believed that internal temp is double  :bug:  Many times I almost s..t my pants when temp on that thermo would spike to 750* (I thought I was running at 1500* internal)


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## pen (Jan 22, 2010)

BeGreen said:
			
		

> Not agreed. The surface temp is not half the inside temp, at least according to Condar. Condar states that interior temps should be about 50% higher than surface temps. That would mean a 400 °F  surface reading would equal about a 600 °F interior temp.



My mistake in reading.  That make much more sense.  I have always "heard" the other to be true and make the mistake of assuming it to be correct.

However, reading it that way makes the problem is even worse!  Since a 300 degree exterior stove pipe should only be registering 450 then, and I am getting 1000!

It's reading looked reasonable when it was at room temp BTW

pen


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## Highbeam (Jan 22, 2010)

BeGreen said:
			
		

> Not agreed. The surface temp is not half the inside temp, at least according to Condar. Condar states that interior temps should be about 50% higher than surface temps. That would mean a 400 °F  surface reading would equal about a 600 °F interior temp.



How do we know that they aren't talking about surface temps of the stove? Or worse yet, that they just aren't very good at math and got caught in the somewhat easy to fall into trap of assuming since the outside of the pipe is 50% of the inside that the inside should be 50% of the outside. 

Who even knows anymore since condar makes pretty much all of the probe meters and their accuracy is now suspect? I would no sooner believe their instructions than would I believe their meters reading.

I still expect the outside of the single wall to be half of the internal temp. This would be verified by noting that the overfire temp on the rutland is 550 which should correspond with 1000 internal temps which is the overfire temp for metal pipe.


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## Peter B. (Jan 22, 2010)

As of last year about this time, I'd used the same Condar probe for about 20 years and 'trusted' it to the extent that it provided reliable (if not highly accurate) readings.  

With my setup, I have one flue probe hole at 12" above the stove top and one drilling into the stove itself to read catalyst output temperatures directly.  I used to switch the Condar back and forth to get relative readings.

After twenty years' service, I thought it might be time to replace it.

I splurged and bought <several> new Condar thermometers - both flue and catalyst probes, and a stovepipe surface thermometer.

To my surprise, the new flue probe read about 200*-300* higher than the old one - switching them back and forth from the same location and letting each stabilize - during multiple 'test runs' on a fairly constant stove temperature.

Needless to say, with such a disparity, I had no idea which thermometer to trust.

I then bought a pair of identical long stem catalyst probes, figuring they were just 'ruggedized' flue models... hoping to find (at least) two thermometers that might (more or less) agree.

Indeed, the catalyst probes 'agreed' - within 100* of each other... and within 200* of the new flue probe.

The 'agreement' was determined by an (otherwise meaningless) oven test when I used three stabilized temps to compare the readings of seven (7) different thermometers of different types... including a rather old hardware store oven thermometer.

Here are the results:

Relative Thermometer Readings - Oven Test

2/25/09

Nominal Oven Temp - 250
Oven thermometer - 270
Stovepipe (surface) - 300
Old flue probe - 640
Small catalyst - 580
New flue probe - 810
Large cat 1 - 860
Large cat 2 - 900

Nominal Oven Temp - 300
Oven thermometer - 330
Stovepipe (surface) - 350
Old flue probe - 820
Small catalyst - 720
New flue probe - 1060
Large cat 1 - 1140
Large cat 2 - 1140

Nominal Oven Temp - 500
Oven thermometer - 510
Stovepipe (surface) - 500
Old flue probe - 1300
Small catalyst - 1200
New flue probe - 1700
Large cat 1 - 1880
Large cat 2 - 1780

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From the above, it's easy to see that the oven trial *IS* (in fact) meaningless when it comes to 'testing' *probe* accuracy... though the *surface* thermometer was in pretty close agreement with the actual oven temp... but that's when it's completely 'immersed' in a constant temp within the oven... not sitting on the stovetop, exposed to ambient air.

When all was said and done, I felt confused and defeated... unable to determine which (if any) of the thermometers could be described as 'accurate'.  For most of the rest of the season last year, I just used the old flue probe in the same location... because I knew what to expect in terms of the live fire and catalyst operation.

This year, I swallowed hard and gave the nod to the paired cat probes... but know they aren't particularly accurate either as catalyst light off isn't reliable until the stove internal probe reads better than 1000*.

So... much as I'd like to have a fairly inexpensive ACCURATE thermometer, I guess I'll have to go on dreaming.

Peter B.

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## karri0n (Jan 22, 2010)

Up until now, this thread, the probe thermometer has been the end-all in terms of accuracy; if someone was getting funky thermometer readings, the answer was "try a probe type". It now seems a very specific set of curcumstances needs to be met in order for these to be accurate. What's worse is that there seems to be no simple way we can test the accuracy of these models:

It's assumed that, for double wall pipe, a probe type is the only viable option for accuracy. If the device is designed for double wall, and the bimetallic element is located directly behind the face, it makes sense as to why using it on single wall pipe will get a much higher reading. However, given what we have learned in this thread, how can we possibly test the accuracy of these units in a double wall setup?

The standing belief that internal temps on single wall will be double the external temps has now been challeneged, and there has never been an accurate ratio for external to internal pipe temp on double wall. This means, in a double wall setup, we cannot use an external thermometer to compare the results to the probe thermometer. Comparing probe temp to stovetop temp might be a viable option, except that the ratio of stove top temp to pipe internal temp will vary wildly from stove to stove, and will be very dependent on how efficiently the stove is radiating the heat into the living space, whther the stove is using a blower, and where exactly on the stove top we are reading.

Even Peter B's test has shown that the accuracy of these things has a decent amount of swing even between two units of seemingly the same model.


Consider the waters very troubled at this point. This thread has shattered quite a few assumptions for two pages.


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## begreen (Jan 22, 2010)

I'm not sure that is a valid test for a flue probe. They are not a simple coil thermometer are they? Could be wrong but I would think that heating up body would give erroneous results. Holding them, probe only in a known high temp environment would seem a more valid test for this kind of thermometer. Maybe boiling water - 212 °F, a barbecue lid vent in a hot barbecue? or perhaps a low propane flame??


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## pen (Jan 22, 2010)

Just straightened out the face/dial on the "broken" one that was initially sent to me and put it in place of the replacement.  Same exact readings.  

The best results testing it would come from me firing up my deep fryer.  But instead I think,,,,,,, wait a minute.......... russet potatoes in the pantry.....

  

brb

pen


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## Diabel (Jan 22, 2010)

That 900* looks high, I don't think it reads correctly. My stove top is cooking at 650* & with a probe thermo.  18" up (DW) it reads 600*


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## Battenkiller (Jan 22, 2010)

OK, my curiosity has gotten the best of me.  I think I've decided what I'm going to do.  

My IR thermo takes K-type thermocouple probes.  On Monday I'll try to remember to get the one that my supplier recommends for the task. It should only set me back about $30 (donations will be accepted via Paypal, lol).  I will drill a 1/8" hole and insert the probe, then take a simultaneous surface reading with the IR.  Should be accurate to +/- a few degrees.  At least that will give me a benchmark score at 18" above the collar for both internal and external temps.  I'll share the results here.  Then I'll put a sheet metal screw in the hole and use the external after that.  

And yes, I have a single wall pipe.


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## pen (Jan 22, 2010)

Battenkiller said:
			
		

> OK, my curiosity has gotten the best of me.  I think I've decided what I'm going to do.
> 
> My IR thermo takes K-type thermocouple probes.  On Monday I'll try to remember to get the one that my supplier recommends for the task. It should only set me back about $30 (donations will be accepted via Paypal, lol).  I will drill a 1/8" hole and insert the probe, then take a simultaneous surface reading with the IR.  Should be accurate to +/- a few degrees.  At least that will give me a benchmark score at 18" above the collar for both internal and external temps.  I'll share the results here.  Then I'll put a sheet metal screw in the hole and use the external after that.
> 
> And yes, I have a single wall pipe.



That will be a great comparison.  I can't wait

pen


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## pen (Jan 23, 2010)

Well, all I can say is these are my results.  They are of course open to interpretation.  I certainly hope nobody is using dial up  :coolsmirk: 

Moved the probe higher up on the flue pipe 






Got everyone jumping at the party






Would you like me to supersize that for you?  BTW, the oil thermometer is reading 358 f






Close up in hot oil






And the every famous shot in the hot tub.  BTW, when fully submerged and left in the boiling water, the probe cruised at 600 flat.


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## Diabel (Jan 23, 2010)

I love that last pic!

btw. How do you insert such large & high quality photos?


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## pen (Jan 23, 2010)

Diabel said:
			
		

> I love that last pic!
> 
> btw. How do you insert such large & high quality photos?



I use the MultiFocus feature on my camera for close-up shots (it's the button w/ the flower on it) and I upload my photos to photobucket.com and then link them to here using img tags around their url 
	

	
	
		
		

		
		
	


	




pen


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## begreen (Jan 23, 2010)

That pretty much says it. Based on what I'm seeing, I don't trust these new probes.Wonder if they got a bad batch?


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## pen (Jan 23, 2010)

BeGreen said:
			
		

> That pretty much says it. Based on what I'm seeing, I don't trust these new probes.Wonder if they got a bad batch?



That's why I say it's open to interpretation.  Is it possible that the probes can't be accurate in the circumstances I just placed them in?  Do they work some other way that I cannot consider?  They do have a bimetalic strip coil behind the dial.  I'll post a pic here in a minute.

pen


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## begreen (Jan 23, 2010)

Yep, they do, I just checked that out. Seems like very bad calibration or the wrong coil on them.


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## pen (Jan 23, 2010)




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## Diabel (Jan 23, 2010)

pen said:
			
		

> Diabel said:
> 
> 
> 
> ...



Thanks!

I use my phone & then upload through the forum. Next time I will use my camera & upload through the pb. It sounds like a lot of work though....


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## pen (Jan 23, 2010)

Any else out there willing to hard boil their probe thermometer so we can compare the results? 

Your wife will only think you are nuts for a little bit.  Well, unless of course you really are nuts then she'll continue to think so.  But if that's the case,,,, meanwhile, back at the ranch.  

Mine read nearly 500 when it was submerged in boiling water up to about an inch from the face.

It read 600 when fully submerged.

pen


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## WES999 (Jan 23, 2010)

I just checked my Fisher that's burning as I type. Single wall pipe. The Condar magnetic thermometer is reading about 340 °F , the thermocouple probe is reading about 550 °F ,
I checked the Cnondar with a digital surface probe and it read about 310 °F .
(BTW the pic is an older one taken when the stove is not running.)
It sure looks like your Condar probe is reading high.
I think a digital probe is the way to go.


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## Battenkiller (Jan 23, 2010)

Wes, that's about the same 50% difference BeGreen said it should be.  Looks like his info from Condar is correct, but the maker's probes themselves are wrong... or at least this one is.


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## pen (Jan 23, 2010)

Battenkiller said:
			
		

> Wes, that's about the same 50% difference BeGreen said it should be.  Looks like his info from Condar is correct, but the maker's probes themselves are wrong... or at least this one is.



Remember I've got 2 probes.  The first one ordered came damaged (face was smashed) and the other is the replacement.  For testing purposes I have fixed the face on the damaged one and both are reading similarly.

Bad batch?

pen


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## Highbeam (Jan 23, 2010)

I love the hot tub test and the fat test. I only wonder if since the coil is above the water/oil that the heat rising from the liquid is heating the coil. I would expect condar to design this probe so that the coil is in ambient air and not in the steam which is of course hotter. I am quite certain that the air temp around that coil will have huge effects on the coil as shown by simply blowing on the coil with lung power. 

I'm holding on to hope but am slowly starting to believe that these meters are crap. 

How can we adjust them? Any word from Condar yet?


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## begreen (Jan 23, 2010)

I have tried to discount the testing methods, especially the oven method for testing a probe thermometer assuming the same thing. One would think that they may be adjusting calibration for ambient air cooling. However, that doesn't explain the large discrepancy when it is properly mounted on a flue pipe. It seems something is seriously wrong with this batch. My Condar probe is the old style with a solid black face. It's readings seem to consistently correlate with the stove top temps, but I may test it externally if we have a fire again this winter.


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## Diabel (Jan 23, 2010)

I was boiling eggs this morning...& stuck the probe in the water expecting to read around 215* -------it read 410* The steam must be affecting the temp!


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## pen (Jan 23, 2010)

too much steam aye?  BRB  :coolsmirk:


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## pen (Jan 23, 2010)

How about this.... Temperature inside of the cup was 160 when this picture was taken.  No steam here.






I just can't come up w/ any way to give credence to anything this thing is reading........ with one exception!  It looks (in my estimation) to read correctly at room temperature at the bottom of it's scale!

pen


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## pen (Jan 23, 2010)

Highbeam said:
			
		

> I love the hot tub test and the fat test. I only wonder if since the coil is above the water/oil that the heat rising from the liquid is heating the coil. I would expect condar to design this probe so that the coil is in ambient air and not in the steam which is of course hotter. I am quite certain that the air temp around that coil will have huge effects on the coil as shown by simply blowing on the coil with lung power.
> 
> I'm holding on to hope but am slowly starting to believe that these meters are crap.
> 
> How can we adjust them? Any word from Condar yet?



I emailed Condar at about 1:30 in the Afternoon Friday.  By the close of business I had 2 different emails from them and confirmation that I'd here from their chief tech guy on Monday (he took off early Friday). 

The communication has been top notch.  I explained what I was experiencing and sent pictures as well.  here is what they have replied with so far

This first communication is what the Marketing Director Mike Whitt CC'd to me as he passed it on to the Plant Supervisor, Carolyn 



> Carolyn –
> 
> I know that Rutland thermometer readings represent a compromise between stovetop and surface temps but I can’t explain the 900 degrees on the Fluegard.  Any ideas?



Here is his 2nd email



> The Condar Company has extensively tested our competitor Rutland’s thermometer and learned that it’s indicated "optimal operating zone" is a one-size-fits all compromise between what's recommended by manufacturers for stovetop use (400 to 600 F) and what's recommended for stovepipe use (230 to 475 F).
> 
> Regarding the FlueGard reading 900 F, our tech guy left early today so I can’t give you an answer about that until Monday.  Our plant manager (Carolyn) would prefer we seek his input before replying.
> 
> ...


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## begreen (Jan 23, 2010)

Ok, I just tried our Condar on the gas cooktop with the probe directly over a low flame. The probe was placed so that a full 2" of it was heated. After 5 minutes the thermometer was reading 775 °F, the IR reading on the probe itself was 803 °F.


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## Peter B. (Jan 23, 2010)

BeGreen said:
			
		

> However, that doesn't explain the large discrepancy when it is properly mounted on a flue pipe. It seems something is seriously wrong with this batch. My Condar probe is the old style with a solid black face. It's readings seem to consistently correlate with the stove top temps



If it's a bad batch, it's been 'bad' since this time last year when I bought the thermometers I posted about previously in this thread.

I was reluctant to bash Condar then (and never used their name in a post I made here at the time), but there weren't any other posters correlating what I'd found.

Now, however...



			
				pen said:
			
		

> I just can't come up w/ any way to give credence to anything this thing is reading.



Condar does not guarantee accuracy... or even accuracy within +/- degrees, so I guess they're 'covered'.

But I consider I have about $75. invested in thermometers I can't trust to be accurate within 250* or so... which is a pretty wide margin.

I honestly think Condar needs to either work on quality control or make some <explicit> statements on how their thermometers are to be used (e.g. single/double wall flue) and what realistic expectations for accuracy they offer.

Again, I used one of their flue probes for all of twenty years, and came to rely on it.  But I don't feel like I can rely on their current offerings.

Peter B.

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## pen (Jan 23, 2010)

BeGreen said:
			
		

> Ok, I just tried our Condar on the gas cooktop with the probe directly over a low flame. The probe was placed so that a full 2" of it was heated. After 5 minutes the thermometer was reading 775 °F, the IR reading on the probe itself was 803 °F.



Just tried to do the same myself but my IR thermometer wouldn't read the probe tip.  I think it's too small an area for mine.

Sounds like I'd trust yours though.  And since that's the case...........

You in the mood to make some tea   ?  

If so, you then you can stick the end in the boiling water and see what you get.  From what I did, the steam doesn't matter.  So an open pot or kettle would be fine.

Since my IR won't keep up, that seems like the only way we can do this apples to apples or probe to probe.  (hmm. probe to probe just doesn't sound appropriate  :ahhh: )

pen


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## Peter B. (Jan 23, 2010)

BeGreen's probe and my old (trusted) one may be - if not the same vintage - then the same model (# 3-19)... black dial.

I still trust my old one for a greater accuracy than _any_ of the new thermometers I bought.

Wish I could find another identical pair of the old model... and use them for another twenty years.

Peter B.

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## pen (Jan 23, 2010)

Funny thing is the box only says that they are good for about 4000 hours of use 

pen


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## Peter B. (Jan 23, 2010)

pen said:
			
		

> Funny thing is the box only says that they are good for about 4000 hours of use



Which - at 8,760 hours per year - might get you through a single Wisconsin heating season.

--

'Brewing some tea' now... report in a bit.

Peter B.

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## begreen (Jan 23, 2010)

Peter B. said:
			
		

> BeGreen's probe and my old (trusted) one may be - if not the same vintage - then the same model (# 3-19)... black dial.
> 
> I still trust my old one for a greater accuracy than _any_ of the new thermometers I bought.
> 
> ...



Yep, our SandHill stove top thermometer is now 30 years old and still accurate within 5 degrees.


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## Peter B. (Jan 23, 2010)

My 'tea test' was inconclusive, I'd say... with about an inch and a half probe length immersed in boiling water, my old (3-19) flue probe and the new (3-39) flue probe (which replaced the 3-19) read <about> 400*... within 50*-100* of one another.

In the kitchen gas stove burner flame test, the new probe read about 750*; the old about 600*.

Anyways...

I'll be curious what Condar has to say.

Peter B.

-----


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## Todd (Jan 23, 2010)

WES999 said:
			
		

> I just checked my Fisher that's burning as I type. Single wall pipe. The Condar magnetic thermometer is reading about 340 °F , the thermocouple probe is reading about 550 °F ,
> I checked the Cnondar with a digital surface probe and it read about 310 °F .
> (BTW the pic is an older one taken when the stove is not running.)
> It sure looks like your Condar probe is reading high.
> I think a digital probe is the way to go.



I think if we all want accurate measurements we all need something like Wess has set up. Thermocouple probes are much more accurate than the spring dial types which are more suited to be used as a rough guide.


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## DanCorcoran (Jan 23, 2010)

If I remember correctly from my Navy electronics training, analog measuring devices are truly accurate only near the middle of their range.  I don't know (but doubt) if this applies to digital devices.


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## pen (Jan 23, 2010)

Peter B. said:
			
		

> My 'tea test' was inconclusive, I'd say... with about an inch and a half probe length immersed in boiling water, my old (3-19) flue probe and the new (3-39) flue probe (which replaced the 3-19) read <about> 400*... within 50*-100* of one another.
> 
> In the kitchen gas stove burner flame test, the new probe read about 750*; the old about 600*.
> 
> ...



Well, it is at least good to know that mine isn't the only one to read high in boiling water.

pen


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## mikepinto65 (Jan 24, 2010)

All this is making me and my two Condar thermos feel dirty!
Looking forward to hearing the techs response.....this would definitely explain my higher than most flue readings.


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## Troutchaser (Jan 24, 2010)

I just installed the Condar probe into my double wall about two weeks ago.  It will go from 0-1200deg. in ten minutes if I leave everything wide open.  I thought that was normal, now I'm wondering if it's actually that hot.  

If I did what the manual stated and filled up with kindling and then small splits and ran wide open to establish a coal bed, the Condar would indicate a melt down-I suspect-maybe even send out a 911 to the fire department.  I do have to trust it somewhat though.  No other choice.


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## Peter B. (Jan 24, 2010)

Peter B. said:
			
		

> Condar does not guarantee accuracy... or even accuracy within +/- degrees, so I guess they're 'covered'.



Actually, I was wrong... at this page on Condar's site:

http://www.condar.com/probe_meters_dir4use_woodstoves.html

... which outlines directions for use of the FlueGard (3-39), is the flat statement:

"When properly installed, the FlueGard accurately reads flue-gas temperatures, with an error margin less than 5%."

So... one might reasonably (like to) expect that to be true.

--

Incidentally, here:

http://www.condar.com/stovepipe_meters.html

... it's stated that:

"Long-stemmed probes give you the most precise and immediate temperature readings, *for either single or double-wall stovepipe.*

(The bold type is Condar's.)

Peter B.

-----


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## Troutchaser (Jan 24, 2010)

Their site says the end of probe should be centered inside of the flue.  I do not do that.  I'll try it and see what the difference is.  I just thought you stuck the sucker in flush to the pipe.  Don't think that tidbit was on their packaging.


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## Todd (Jan 24, 2010)

Troutchaser said:
			
		

> Their site says the end of probe should be centered inside of the flue.  I do not do that.  I'll try it and see what the difference is.  I just thought you stuck the sucker in flush to the pipe.  Don't think that tidbit was on their packaging.



I wonder if you can cut them down? It's a 4" probe which would make it center on an 8" pipe. Cut an inch off and it should be center in a 6" pipe.


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## Troutchaser (Jan 24, 2010)

Todd said:
			
		

> Troutchaser said:
> 
> 
> 
> ...



Who goes first?


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## Todd (Jan 24, 2010)

Troutchaser said:
			
		

> Todd said:
> 
> 
> 
> ...



I know someone that already did it with a Condar cat probe for his WS Keystone, (rmcfall) and he said it works fine. https://www.hearth.com/econtent/index.php/forums/viewthread/47694/P0/


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## WES999 (Jan 24, 2010)

I think what needs to be done is to install a Condar probe and thermocouple side by side in a actual stove pipe,  and run the stove from 0 °F to say 1000 °F and record the the temps from both and compare them.

If anything the Condar should read a little lower than the thermocouple as the response time is slower than for a thermocouple.

Anyone have an extra Condar they would like to see tested?
I could test them both and post the results.


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## Todd (Jan 24, 2010)

I cut mine down to a 3" probe so it's smack dab in the middle of the pipe. I still get the same high readings, doesn't make any difference. This is on sigle wall pipe. 1st pic is in the bypass mode, the internal really takes off and is more than double the external temps. 2nd pic is about 1 hour after engaging the cat the internal settles down to just about half the external.


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## Peter B. (Jan 24, 2010)

Todd said:
			
		

> 1st pic is in the bypass mode, the internal really takes off and is more than double the external temps. 2nd pic is about 1 hour after engaging the cat the internal settles down to just about half the external.



My experience has been that higher temps (above 500*) are more likely to produce greater inaccuracies...

Peter B.

-----


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## Todd (Jan 24, 2010)

Another thing to point out in my 2nd picture is with the magnetic external thermometer I'm barely in the good burn color coded zone which starts at 250, in fact after a couple hours it usually drops below. The internal probe I'm right in the middle of the good burn zone.


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## begreen (Jan 24, 2010)

WES999 said:
			
		

> Anyone have an extra Condar they would like to see tested?
> I could test them both and post the results.



Looks like pen has a flock of them. Maybe he can send one to you for verification?


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## pen (Jan 24, 2010)

WES999 said:
			
		

> I think what needs to be done is to install a Condar probe and thermocouple side by side in a actual stove pipe,  and run the stove from 0 °F to say 1000 °F and record the the temps from both and compare them.
> 
> If anything the Condar should read a little lower than the thermocouple as the response time is slower than for a thermocouple.
> 
> ...



PM me your address and I'll mail the one I have w/ a damaged face to you.  If it gets crushed in shipping (again) no harm no foul.

pen


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## pen (Jan 25, 2010)

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

pen


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## Troutchaser (Jan 25, 2010)

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


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## Todd (Jan 25, 2010)

Troutchaser said:
			
		

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



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


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## 3fordasho (Jan 25, 2010)

I didn't have much luck with the Condor probe flue thermometer, replaced it with:
http://www.teltru.com/p-272-big-gre...ent-thermometer-lt225r-2001000-degrees-f.aspx
Been happy with it so far, only down side I can see is it doesn't like being zinged past 1000F.   This one is also able to be re-calibrated, hold the hex nut on the back and turn the dial until it reads correctly.


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## Todd (Jan 25, 2010)

Any word from Condar yet?


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## pen (Jan 25, 2010)

Todd said:
			
		

> Any word from Condar yet?



no word today

pen


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## pen (Jan 25, 2010)

Todd said:
			
		

> Troutchaser said:
> 
> 
> 
> ...



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

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

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

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

pen


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## begreen (Jan 25, 2010)

3fordasho said:
			
		

> I didn't have much luck with the Condor probe flue thermometer, replaced it with:
> http://www.teltru.com/p-272-big-gre...ent-thermometer-lt225r-2001000-degrees-f.aspx
> Been happy with it so far, only down side I can see is it doesn't like being zinged past 1000F.   This one is also able to be re-calibrated, hold the hex nut on the back and turn the dial until it reads correctly.



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


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## 3fordasho (Jan 26, 2010)

BeGreen said:
			
		

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




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


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## Todd (Jan 26, 2010)

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


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## 3fordasho (Jan 26, 2010)

Todd said:
			
		

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




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


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


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## Highbeam (Jan 26, 2010)

Todd said:
			
		

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



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

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


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## Todd (Jan 26, 2010)

Highbeam said:
			
		

> Todd said:
> 
> 
> 
> ...



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


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## 3fordasho (Jan 26, 2010)

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


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## pen (Jan 29, 2010)

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

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

Good Morning, 

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

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






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

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

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






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

Thank you,


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## redhotz (Jan 29, 2010)

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


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## pen (Jan 29, 2010)

Just received 2 speedy responses.

Here they are

            Hi Matt – 



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



Regards,



Mike


*AND*

Matt,



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



Eddie Taylor


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## Peter B. (Jan 29, 2010)

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

--

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



> (Note that flue gas readings are approximately 50% higher than surface temperature readings.)
> 
> Less than 230°F (110°C): Temperature too low.  Incomplete combustion, causing smoke, soot and hazardous creosote.  Open draft and/or add dry fuel.
> 
> ...



--

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



> 100°F to 400°F: Temperature too low.  Incomplete combustion, causing smoke, soot and hazardous creosote. Open draft and/or add dry fuel.
> 
> 400°F to 900°F: Safe operating temperature.  Complete combustion and best efficiency.
> 
> 900°F to 1200°F: Wasting energy, possibly overheating.  While high temperatures are often reached on initial firing, should not be maintained for normal operation.  Reduce draft.



--

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

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

--

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

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

Peter B. 

-----


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## ckdeuce (Jan 29, 2010)

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


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## Battenkiller (Jan 30, 2010)

ckdeuce said:
			
		

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



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


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## begreen (Jan 30, 2010)

Peter B. said:
			
		

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



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


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## Todd (Jan 30, 2010)

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


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## pen (Jan 30, 2010)

Todd said:
			
		

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



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

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

pen


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## Todd (Jan 30, 2010)

pen said:
			
		

> Todd said:
> 
> 
> 
> ...



 :lol:  :lol:  :lol:


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## pen (Feb 1, 2010)

For those reading this thread down the road......

The results of testing the condar versus an actual thermocouple, and condar's response can be found at here in a new thread.

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

pen


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## Tulip (Jan 14, 2011)

cmonSTART said:
			
		

> Your probe thermometer measures the temperature of the gasses inside the flue.  Your rutland surface thermometer measures surface temp of the pipe.  The surface temperature is just shy of half of the flue temp usually.



This is very interesting. I hope this is the right place to ask my question, since it relates to thermometer accuracy and placement. 

My questions first, then the backstory:
Where should my thermometer(s) be? I have a Rutland and I just got a Condar ChimGard Stovepipe thermometer
Should I have my stovepipe cleaned out and/or inspected before firing up again?

The backstory:
Earlier this week I was happily reading in my favorite chair next to my Petit Godin when I happened to glance over at it and the stovepipe going from the back of the stove to the chimney pipe was glowing red hot. I freaked! Well, I jumped up and shut down the air and things cooled off pretty quickly. Install was all up to code by a pro in November 2009. It uses an existing fireplace. 

I have a Rutland thermometer that I keep on the front of the stove near the door. It was reading about 450-500F at the time. So does that mean that the stove pipe was actually half again as much? Yikes! I was burning well-seasoned wood (may have been cedar) with some bituminous coal mixed in. The Godin is made for coal. The air was all the way open since that's what it takes to get a good burn in the 500F range, or so I thought, but I think I've been mistaken because of my thermometer placement. It's been on the front near the door. 

I'm wondering if I had the thermometer in the wrong place on the stove. I've read through the posts here and other threads about this, and alot of folks keep their thermometer on the top. Does that mean on the top where one would put a steamer? The Godin is cylindrical and there's not much room on the top if I put the steamer on there. Plus, you have to open the top to refuel, requiring removal of the steamer (and the thermometer if it's there). 

I haven't dared light another fire since this happened. I did buy a second thermometer--a ChimGard stovepipe thermometer. I figured I should probably have one on the stovepipe itself, as well as on the stove. 

What do you all think--should I have the stovepipe cleaned out before using it again? There's a T-connection with cleanout. I haven't done it myself but the installer said it was easy and that I could do it, although he didn't mention how often. This is my second season, and I have not cleaned the chimney since the install last November (2009). I don't burn every day, and the season here in Central Virginia is not as long as up north. December-February, I'd say. The install was by a pro, and the chimney pipe (the one going up the chimney) is ceramic lined. The stove pipe (horizontal from back of stove) was silver at first, but now it's been discolored from use. It is not black. I don't know if it's double or single walled, but I will find my work order and find out. 

It's really cold here, and I miss running my stove (and hate running my heatpump so much!) But safety first...

Apologies for the non-technical lingo. I'm still learning. I look forward to your thoughts and advice. 
-Julie


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