What should I do when the BATT warning appears on my thermostat?

Install fresh alkaline AA batteries immediately when the BATT icon, alert icon, and battery icon are displayed on the Home screen. Gently press the thermostat to loosen it from the wall mount, then carefully pull it free to access the battery compartment. If batteries are replaced within two minutes, the time and day will not need to be reset, as all other settings are permanently stored in memory. (Page 6)