Honeywell PRO TH4000 - Manual (Page 18)

Operating Manual
16 69-1760EFS—01
ENGLISH
MCR29478
Batteries are optional (for backup
power) if your thermostat was wired
to run on AC power when installed.
Install fresh batteries when the
REPLACE BATT warning begins flash-
ing. The warning flashes about two
months before the batteries are
depleted.
Replace batteries once a year, or
before leaving home for more than a
month. If batteries are inserted within
one minute, the time and day will not
have to be reset. All other settings are
permanently stored in memory, and
do not require battery power. Pull at bottom to
remove thermostat
from wallplate.
Turn thermostat over,
insert fresh AA alkaline
batteries, then reinstall
thermostat.
Battery replacement