Lennox International Inc. Ellite Series - Manual (Page 19)

Page 19
Battery Replacement
If your thermostat has batteries, a low battery warning flashes
on the home screen for approximately 30 days.
IMPORTANT − Batteries should be replaced once per year to
prevent leakage and to prevent loss of battery back−up in a
power outtage. You may also wish to replace the batteries prior
to leaving your home for more than a month.
1 − When the low battery indicator is flashing, replace the
batteries promptly with three fresh AAA alkaline batteries.
2 − Remove the thermostat from the wallplate by pulling
straight out.
WALL