This is the same thermometer and same reason I'm here now. Mine was purchased towards the end of December 2017 from Lowes. The receipt was misplaced, Lowes is 45 miles away. By the time I got back over to Lowes, no receipt, no exchange, no refund...Yes, frustrated so here I am. I thought I would check online, before pitching it in the garbage and going to the local hardware store to purchase a Taylor or Springfield thermometer.
We are very sorry for any inconvenience you have experienced. Please try the following troubleshooting steps. Please let us know if you have any questions. Thank you.
HOW TO CALIBRATE AN ANALOG THERMOMETER
Analog thermometers may need to be calibrated from time to time or even just after purchasing the product. The pointer may move during shipping, causing the thermometer to read inaccurately. If the thermometer is reading incorrectly, compare the reading to a known accurate thermometer. Let both units adjust for at least three hours. Depending on the product, there may be a knob or screw on the back of the thermometer to calibrate the temperature. If the new thermometer continues to read inaccurately, adjust the pointer by turning knob or screw on the back of the unit in the appropriate direction.
If there is no knob or screw for calibration, you will need to adjust the pointer by hand. If the temperature reading is too low, slowly push the needle up to the highest temperature and then slowly let it follow your finger back down until the needle stops on its own. Never let the needle swing back wildly on its own as this can permanently damage the thermometer. When the needle stops, it will stop a degree or two higher than where it was originally set. Repeat this process until the needle stops at an accurate temperature reading. If the thermometer is too high, follow this same process only pushing the needle down to the lowest temperature. NOTE: Some thermometers may not allow easy access to the pointer. Disassembling may damage the thermometer or void the warranty, and is not recommended.
Note: The instructions are to calibrate temperature, but can also be used to calibrate humidity