HHH or LLL is appearing on the display
The error codes typically indicate that the temperature reading is out of operating range. The optimal temperature range is -4°F to 392°F (-20°C to 200°C).

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The backlight is not turning on
Try changing out the old battery with a new CR2032 to see if it will help. If the issue persists, please contact our customer support: https://kitchensupply.com/pages/support