Lid thermometer way off


 

Ron Fisher

TVWBB Member
Picked up an 18.5 that is in great shape on Craiglist last week. Stupidly didn't test the lid thermometer against my electronic guages. Set 3 racks of St Louiees on the top grate for 3 hours with the lid thermo showing a rock steady 250ish.... opened the lid and those suckers were done! Tested the temp at the top vent and it was 40 degrees higher than the built in.. I won't be trusting that sucka again!
 
I find its really off when you add cold meat. It eventually gets closer. The bottom without water cooks even hotter. I had chicken on both grates. The bottom was 13 degrees more done
 
I find its really off when you add cold meat. It eventually gets closer. The bottom without water cooks even hotter. I had chicken on both grates. The bottom was 13 degrees more done

I'm alright with it cooking hotter, I just didn't know that it was much hotter than the thermometer indicated. Still managed some great BBQ. I did do this batch without water minion mode, I think the next one I'll try water
 
the lid thermometers are known to be wildly inaccurate. only thing i trust are my maverick food/grate probes.
 
the lid thermometers are known to be wildly inaccurate. only thing i trust are my maverick food/grate probes.

My WSM gage runs on the cool side compared to my ET 732 and DigiQ DXII. Same with my Kettle.

I like the maverick too. Just don't get them wet where the cable connects to the probe; otherwise, they will fail in short order. I have not found a good replacement probe set that's a little more resistant to moisture, having gone through several over the years, despite handling the probes and cables with kid gloves. It is interesting that I have never had an issue with my temp control probes.

CraigW
 
Wanted to bring this old thread up because I'm experiencing the same thing.

My lid temp is at least 50 degrees lower than what my ET 733 says..

On my first few cooks, the lid temp was much higher. It's almost as if the carbon buildup is causing the temps to read differently.
 
Alfred... Do you run water in the pan ? In those past cooks, did you run water in the pan ? Where is your ET 733 probe located, relative to the meat ?
 
I've heard this for years, but when I got my WSM this year was pleasantly surprised. My dome therm is usually close to my maverick which is boiling water tested as accurate.

Either I'm lucky or weber has improved the therms.

I still use the Maverick but it's nice to have the peace of mind that the dial can be used in a pinch.
 
It's in a different location than the grates, stands to reason it may be "off".
If you really want to know if it's actually measuring the wrong temperature you have to measure at the same location.

More important than it being "off" is whether or not it is a consistent difference from cook to cook once the cooker is running stable and to document the delta with thermometers on the grates.
The WSM thermometer on my cooker is ~25 degrees cooler than the top grate once it is stabilized every time I cook.
 
Just remove it from the lid and test it by inserting the "pointy end" in boiling water. What does it read? 212o--all A-O.K. Off by 10o (reading 202o?? just remember to add 10o when your're cooking--->you want to cook at 250? When it gets to 240, you're at your target temps :) .

Easy peasy.
 

 

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