Honeywell TH1110D1000 Owner's Manual - Page 12

ENGLISH Operating Manual Battery replacement NOTE: Batteries are optional (and serve as backup power) only if your thermostat is connected to 24 VAC. Set the System switch to Off before removing the batteries. Otherwise, the heating/cooling system could remain activated even when batteries are removed. Install two fresh AAA batteries when Lo Batt (low batteries) flashes on the screen. The message appears for 60 days before the batteries are depleted. Replace batteries once a year, or when you will be away for more than a month. The settings are stored in non-volatile (permanent) memory and are thus preserved when the thermostat is without AC power or batteries. NOTE: The low-battery icon will not appear when the batteries are depleted if the thermostat is connected to 24 VAC. 8