Must be Low something. I found these which say they need cleaning internally where the battery is.
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2.0 out of 5 stars
ByG. Gutierrezon March 29, 2017
This thermometer worked well for the first 5 or 6 times we used it, then the readings started to go wacky on subsequent attempts, showing 20°F (-7°C) while switching it on in a room-temperature (72°F) kitchen, and a different value every time it was placed into the same roast. Now it just shows LL.L. Reading through these reviews, I can see that this device requires frequent cleaning. Sure enough, after a disassemble and wipe down, it seems to be reading correct ambient temperatures. But, is it and will it? I don't know. This thing is seriously cheap.
4.0 out of 5 starsGood thermometer with a little maintenance
on December 23, 2014
I purchased the Weber 6492 in the middle of August 2014 and it has worked well up to this week when, as others have reported, the temperature reading starting jumping around and occasionally settled on a non-reading of "LL". I am not ******* my things because I want them to last. I treated this thermometer, in particular, as if it was as fragile as an egg. But four days before Christmas, with baking still to be done, it stopped functioning properly.
I didn't have the time or inclination to go out and buy another thermometer so I figured it was worth trying to change the battery, The battery is accessible by twisting the front part of the housing (the part with the buttons and LCD) counterclockwise in relation to the back.
As it turned out, the battery was fine but the contacts must have had a little oxidation that prevented the front part from communicating with the sensor. After gently cleaning the contacts with a soft piece of fabric, It works fine now.
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