Honeywell TH5110D1006 Owner's Manual - Page 12

Operating Manual Battery replacement ENGLISH Press and pull to remove Auto Replace Batttery MCR29409 Insert fresh alkaline batteries, then reinstall battery holder. TH5110D - AAA alkaline batteries. TH5320U/TH5220D - AA alkaline batteries. 69-1923EFS-01 MCR29411 Batteries are optional (to provide backup power) if your thermostat was wired to run on AC power when installed. Install fresh batteries immediately when the REPLACE BATTERY 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. Batteries provide backup power to the display during power interruptions. All settings are permanently stored in memory, and do not require battery power. 10