Teltru Verses Condar Thermometers

[Todd]

Just received my new Teltru thermometers and thought I'd share some observations. I bought the Teltru GT225 2.5" stem, 2" dial probe thermometer and wow, does it ever react fast! 1st picture is with the stove in bypass with lots of flame in the box, the temps shot up quickly to 600 then I backed down the air to #2 and the thermometer instantly backed off down to 300. I played with the air setting for awhile and brought it up as high as 800 then backed it down to 600 and engaged the cat. Also observed the Condar probe and surface thermometers which lagged way behind the Teltru.

 

[pen]

get a chance to put the condar probe next to the tel-tru probe or swap them out one at a time on a steady cruise to compare?

pen

 

[Todd]

30 minutes after engaging the cat she's settled in for about a 7 hour burn with the air setting at about .8. Looks like the Teltru reads just about double the surface temp of single wall pipe. The Condar probe is way high as we have found out in other testing here. I did pull out the Condar probe about an inch and it did drop about 100 degrees but it just doesn't react like the Teltru.

 

[Todd]

Also bought the Teltru surface therm. It reads about 10-20 degrees higher than the Condar/Woodstock therm.

 

[Todd]

1 hour into the burn, Teltru probe 510, Codar probe 660, Condar surface 270. Stove top, Teltru 580, Codar 570. Looks like the Teltru internal probe is pretty much keeping up with double the surface temps.

I'm going to have to be careful in the bypass mode with the Teltru probe, she shoots up very quickly compared to the Condar's but it also comes down just as fast when you reduce the air. I don't know how these thermometers would work with some non cat stoves, the temp ranges aren't very high and non cats seem to burn a little hotter stack and stove top temps but I think the temp range for my soapstone cat stove should be just about right.

 

[jeff_t]

But the Condar is purtier, more colorful.

Is the Teltru pricy? I might upgrade with the new stove.

 

[Backwoods Savage]

That is interesting Todd. I may consider buying one or two of them but will probably wait until ours start to lose there abilities.

 

[Todd]

1.5 hours in. I also have an SBI probe I stuck in the same hole as the Condar and it reads a little lower.

 

[Todd]

But the Condar is purtier, more colorful.

Is the Teltru pricy? I might upgrade with the new stove.

The probe is about twice the cost of the Condar's but they seem much quicker to respond since the coil is inside the probe tip and they are not influenced by the radiant heat from the pipe. I like it, but I wish the dial was a little larger.

 

[pen]

But the Condar is purtier, more colorful.

Is the Teltru pricy? I might upgrade with the new stove.

The probe is about twice the cost of the Condar's but they seem much quicker to respond since the coil is inside the probe tip and they are not influenced by the radiant heat from the pipe. I like it, but I wish the dial was a little larger.

Did you contact tel-tru about using it in a flue?

Just curious what their thoughts are on the longevity of the unit in this application. Condar has claimed that there external units should be good for life but that the probes are only rated for 4000 hours (even though we have users w/ more hours than that on old units which are still holding their own and external units which have gone to pot).

pen

 

[Todd]

But the Condar is purtier, more colorful.

Is the Tel pricy? I might upgrade with the new stove.

The probe is about twice the cost of the Condar's but they seem much quicker to respond since the coil is inside the probe tip and they are not influenced by the radiant heat from the pipe. I like it, but I wish the dial was a little larger.

Did you contact tel-tru about using it in a flue?

Just curious what their thoughts are on the longevity of the unit in this application. Condar has claimed that there external units should be good for life but that the probes are only rated for 4000 hours (even though we have users w/ more hours than that on old units which are still holding their own and external units which have gone to pot).

pen

No, I didn't talk to them and I didn't read anything on longevity, guess I'll find out. I think Begreen had a discussion with them a while back, maybe he has some info?

 

[rdust]

I think you have a problem other than the one that makes you replace stoves frequently! ;-)

 

[Stump_Branch]

I think you have a problem other than the one that makes you replace stoves frequently! ;-)

Agreed you must let up how the wife lets you do this. I had to tread lightly to get the condar surface and probe...

 

[Todd]

I think you have a problem other than the one that makes you replace stoves frequently! ;-)

Agreed you must let up how the wife lets you do this. I had to tread lightly to get the condar surface and probe...

Ha ha, the wife doesn't even notice, she's at work when UPS shows up. I know I have too many thermometers but I like to tinker with this kind of stuff. I would of bought a thermocouple but don't like the look of the hard wire running from the probe to the readout. I'm down to 2 thermometers now, one for the stack and one for the stove top, took the cat probe out so I could set a kettle on top for a little extra humidity and found that I really don't need it when burning 24/7, it's better for cold starts during the shoulder season.

 

[Todd]

That is interesting Todd. I may consider buying one or two of them but will probably wait until ours start to lose there abilities.

I think you would be amazed at how quickly these probes react to an adjustment from the air control. When I was at 800 the air was full, when I backed it down to #2 it instantly dropped down to 600 and stayed there til I engaged the cat, then it dropped again down to 500. You can also see the difference almost immediately when you make very slight air adjustments. The Condar probes take much longer to react and don't work well on single wall due to the pipes radiant heat. The magnetic surface therms are even slower.

 

[3fordasho]

I'm running the same tel-tru and really like it. Like you've reported they react very quickly and if you're not watching things on a start up or reload you can peg the needle at 1000f. Once you do this it will not read the same, but you can re-calibrate it. Best not to do it in the first place. One time I pegged it and the extra heat/ flames in the flue touched off a bit of creosote in the connector piping. Needless to say, I now keep it under 600-700F and have never had a repeat.

That is interesting Todd. I may consider buying one or two of them but will probably wait until ours start to lose there abilities.

I think you would be amazed at how quickly these probes react to an adjustment from the air control. When I was at 800 the air was full, when I backed it down to #2 it instantly dropped down to 600 and stayed there til I engaged the cat, then it dropped again down to 500. You can also see the difference almost immediately when you make very slight air adjustments. The Condar probes take much longer to react and don't work well on single wall due to the pipes radiant heat. The magnetic surface therms are even slower.

 

[Todd]

I'm running the same tel-tru and really like it. Like you've reported they react very quickly and if you're not watching things on a start up or reload you can peg the needle at 1000f. Once you do this it will not read the same, but you can re-calibrate it. Best not to do it in the first place. One time I pegged it and the extra heat/ flames in the flue touched off a bit of creosote in the connector piping. Needless to say, I now keep it under 600-700F and have never had a repeat.

Your posts about the teltru therms is what convinced me to buy them. I definitely noticed how easy it is to peg these probes. Once the fire catches watch out, she shoots up quick but as soon as this happens you should back her down and keep the heat in the stove.

 

[3fordasho]

FWIW you can get the tel-tru's in much larger dial sizes if you want. I scored (Ebay) a lot of 5" dia 200-1000F units with the probe 90 deg from the face and they work great on my 2nd fireview install with the connector pipe straight out the back to class A tee /wall thimble.

I'm running the same tel-tru and really like it. Like you've reported they react very quickly and if you're not watching things on a start up or reload you can peg the needle at 1000f. Once you do this it will not read the same, but you can re-calibrate it. Best not to do it in the first place. One time I pegged it and the extra heat/ flames in the flue touched off a bit of creosote in the connector piping. Needless to say, I now keep it under 600-700F and have never had a repeat.

Your posts about the teltru therms is what convinced me to buy them. I definitely noticed how easy it is to peg these probes. Once the fire catches watch out, she shoots up quick but as soon as this happens you should back her down and keep the heat in the stove.

 

[Todd]

How did you install your probes. At first I drilled a small hole the size of the probe but it didn't fit tight enough so I drilled a 3/8" hole and screwed it into the pipe.The 3/8 threads seemed to be just the right size to screw right into the pipe. I might take the pipe apart and put a nut on the inside to make sure it's snug but it seems pretty tight the way it is.

 

[3fordasho]

I used a small brass hose barb (1/8"or 3/16" id hose x 1/8"male pipe thread). Drilled through the brass fitting so the Tel-tru probe would be slip fit though it. The connector pipe was drilled a larger diameter to enable the pipe thread portion of the brass barb to thread into it. After some use there will be build up on the probe so it will no longer slide through the drilled out barb fitting but one can still unthread the entire unit as an assembly.

How did you install your probes. At first I drilled a small hole the size of the probe but it didn't fit tight enough so I drilled a 3/8" hole and screwed it into the pipe.The 3/8 threads seemed to be just the right size to screw right into the pipe. I might take the pipe apart and put a nut on the inside to make sure it's snug but it seems pretty tight the way it is.

 

[Todd]

You must have a different back without the threads?

 

[3fordasho]

You must have a different back without the threads?

Yes. This one:
http://www.teltru.com/p-272-big-gre...ter-lt225r-5-inch-stem-2001000-degrees-f.aspx


Good for my Big Green Egg too ;-)

 

[Stump_Branch]

I find myself wondering who came up with the 18in rule. I like the plain face. More scientific looking. I bought condars medallion stove top thermo for the equally plain face. No wood burning markings. Ill imagine that these marking were put on by various brands and 18in was just where it worked best.

Id think that to keep from pegging the thermo on the tel-tru, you could place it higher in the stack. Youll still see the quick reaction just at a lower reading. If its really about half the surface you could learn to adjust to this new range of numbers. Rather than 800 to 600 its 600 to 400 etc.

 

[Todd]

I find myself wondering who came up with the 18in rule. I like the plain face. More scientific looking. I bought condars medallion stove top thermo for the equally plain face. No wood burning markings. Ill imagine that these marking were put on by various brands and 18in was just where it worked best.

Id think that to keep from pegging the thermo on the tel-tru, you could place it higher in the stack. Youll still see the quick reaction just at a lower reading. If its really about half the surface you could learn to adjust to this new range of numbers. Rather than 800 to 600 its 600 to 400 etc.

I think the 18" rule came from Condar. They probably calibrate their thermometers with thermocouples and found they needed to get them up the stack a bit away from the fire more into the flue gas stream.

My Teltru is 20" up right below my 90 elbow. There really is no recommendation from Teltru where the probe should be located, I think I'll ask them. So far it's been reading slightly below half the external temps. 400-500 probe is about 250-300 surface. It's much more noticeable with the probe when you make air adjustments than waiting on the surface therm to wait for the pipe to cool down.

 

[Todd]

Here's an email response I received from Teltru when I asked them about the longevity of their probe in a wood stove flue.

Dear Todd,


Thank you for contacting us.

We really appreciate you choosing our product and providing feedback. Unfortunately, a bimetal probe thermometer may not be suitable for monitoring temperature within a wood stove flue because of the temperatures. I caution you not to expose the thermometer to temperatures above 800F regularly because the sensor is made of 2 dissimilar metals that need to be able to expand and contract to work correctly. Exposure to temperatures above 800F and cooled will harden metals over a period of time so the accuracy will be degraded and the pointer will likely stop indicating. Because your thermometer is seeing extreme varied temperatures you should check your thermometer accuracy as often as you feel is necessary