Honeywell TH4210D Thermostat User Manual


 
Installation Guide
6
AC Power
The thermostat can be powered by 24
VAC power, or by batteries.
To wire the thermostat for AC power,
connect the common side of the
transformer to the “C”terminal as
shown at left.
Connect common
side of transformer
to “C” terminal
Install batteries in back of thermostat
(optional if AC powered).
Battery Power
The thermostat can be powered by
batteries alone or, if used with AC
power, can provide backup power.
During power interruptions the
batteries will save time/day settings
and power the display.
To Mount Thermostat
Align the 4 tabs on the wallplate with
corresponding slots on the back of the
thermostat, then push gently until the
thermostat snaps in place.
Power options & mounting