Sorry to hear you're having a problem. I am on my second one in two weeks. While checking the first one in a Boveda test kit, the temp kept jumping around. I checked the min and max readings in the morning and it showed a low of 14 degrees F and a max of 103. I dont have that big of a temperature swing in my house so I exchanged it for another. Im testing the new one now. I didn't see the temp jumping around but I did get a max temp reading of 90 when I checked it early on, so I reset the min/max using the buttons to make sure this wasnt just an anomaly when first turned on. I called Western Humidor and they said to take the battery out for a minute and then put it back. This will reset the unit. If you can, test the battery to make sure its OK or put a new one in just to rule it out. If you still have the problem, return it. I have another one that I purchased over a year ago and have had no problems with that one. They are supposed to be good hygrometers for the price range. Sometimes you just get a bad one (or two). Hope this helps.
