I have a Maple Chase home electronic programmable thermostat. No model # on unit. Even after I take front cover off. Probably 10 years old. I set night temp to 65 and the other 3 settings to 70 I winter. The unit however will suddenly drop the day temp to 65. I have pressed the reset button and reprogrammed the thermostat. It still continues to drop the temp during the day at unpredictable times. Batteries are fine. The reverse doesn't happen at night.