Owner`s manual

Operating the Thermostat
35
Changing the batteries
Your thermostat is probably powered by the HVAC equipment, but
if it isn't, it's battery powered. You can tell if it’s battery powered by
checking in Advanced Programming Options. (See page 38.) If there’s
no lighting until you touch a button, it’s battery powered. When the
thermostat uses electricity, the batteries (if installed) take over if the
electricity goes out. This allows you to monitor the indoor temperature
when there’s no electricity.
When powered by batteries, your thermostat’s two AA batteries should
last about one year. When your batteries have lost about one-third of
their power, a battery icon shows up on the display in the upper right
corner. Two-thirds of it will be black. As the batteries get weaker, the
icon goes down to one bar and then none. When the battery icon is
less than full, you will first see the loss of backlight function. When
the batteries are completely dead, you won’t be able to use the
thermostat.