Honeywell TH3110B Owner's Manual - Page 11

PRO TH3110B Digital Thermostat Battery replacement Grasp and pull to remove thermostat Turn thermostat over, insert fresh AA alkaline batteries, then reinstall thermostat Install fresh batteries immediately when the REPLACE BATT warning begins flashing.The warning flashes about two months before the batteries are depleted. Even if the warning does not appear, you should replace batteries once a year, or before leaving home for more than a month. Always replace both batteries with fresh,AA alkaline batteries. 9