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Old 11-03-2008, 01:28 PM   #1
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Thermometer Questions...

I'm cooking on a WSM, so let's get that out there right away so all the stick burners can get the "why don't you buy a real pit" stuff out of there systems

Anyway I have a Tel-Tru thermometer 2 1/2" stem mounted in the lid opposite the lid vent. I have checked the accuracy of this thermometer several times and in boiling water and ice water it is within 2º, so it's basically right on. If I insert a digital probe thermometer (which I have also tested and is accurate) in the lid vent I get readings that are anywhere from 20-35º different then the reading coming from the Tel-Tru.

For example, I cooked a brisket Friday night and the temps on my digital probe in the lid were pinned at 257-266 the entire cook while the Tel-Tru was registering between 225 -235.

Why? Any ideas, is it that the exhaust air is hotter than the air circulating near the Tel-Tru therm? That's the only thing I can figure out? Inquiring minds want to know.
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Old 11-03-2008, 01:43 PM   #2
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You said you tested them in boiling water correct? 212 degrees correct? You have no idea if they are acurate higher than that , correct? Could be the mechanical parts in the tel-tru.. I would trust the digital at all temps.. That is all I can think is wrong..
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Old 11-03-2008, 01:52 PM   #3
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Bruce I have noticed the same thing on my WSMs as well as my Primos with no rationale as to why. I do not have a Tel Tru (LT225R)mounted on the WSM, but have stuck it through the exhaust on both grills with the same results. Had the same difference with the Tel Tru and Digi Q thermometer as well...........the Tel Trus ALWAYS run lower than the Digital therms.
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Old 11-03-2008, 02:10 PM   #4
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Bruce, about a week ago I mounted a 2 1/2" Tel-Tru in my WSM, same way as you did, and with the same results. I've been checking it with a Weber ("WARNING HOT") thermometer through the vent, a 4" Reotemp through the vent, and a Maverick at the grate. I can pick whichever temp I like, no two the same. The Tel-Tru looks keen, though.

--John
(Yeah, they all give slightly different readings at 212º, but much closer together than higher up the scale.)
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Old 11-03-2008, 03:39 PM   #5
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I think you are right Bruce the exhaust air is probably hotter then the other air in smoker….it’s that heat wall you get on the outside of the smoker….another thing I’ve noticed is the digital thermo are sensitive to changes in temp…if one of those pieces of wood in the charcoal catches the digital will read higher and the Tel Tru stays the same…you’ll get more spikes with the digital…
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Old 11-03-2008, 04:28 PM   #6
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Why don't you buy a real Pit!


anyway... I have had the same thing with the Tel True in my Lang. I put the Maverick probe on the upper grate not 10" away from where the tel true probe was and it was running 20-30 degrees difference. So am I actually cooking at 250 when my Tel-true says 225... Probably.
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Old 11-03-2008, 04:48 PM   #7
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Quote:
Originally Posted by Gary in VA
I have had the same thing with the Tel True in my Lang. I put the Maverick probe on the upper grate not 10" away from where the tel true probe was and it was running 20-30 degrees difference. So am I actually cooking at 250 when my Tel-true says 225... Probably.
Yeah, I concluded a year or so ago that my "230-250º" is probably more like 250-270º, but that's okay -- I'm used to it and I get the results I want.

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(Maybe just a trifle sooner than some people. )
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Old 11-03-2008, 06:03 PM   #8
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Yea, get a stick burner. Had to say it.
Tel-tru are not accurate. They are junk.
I clipped an electronic probe right to the end of a Tel-Tru and still got 35 to 50 * different in readings. A ten dollar turkey frying therm is much closer.
Go digital.
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Old 11-03-2008, 06:20 PM   #9
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Mechanical thermos are the most accurate at the middle of the scale.
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Old 11-03-2008, 07:34 PM   #10
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Ok I have a stick burner with two manual thermos in it. My Maverick reads 20-25 degrees higher than the manual gauges do. By the way have a WSM also with a Tur-Tel in the lid but never used the Maverick with it.
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