Honeywell Home Wi-Fi Series User Manual page 11

Installing your thermostat
2 Remove old thermostat faceplate
and leave wires connected.
2a Take a picture of the wire
connections for later reference.
2b If no wire is connected to a
terminal labeled C or no C terminal
exists on the old thermostat,
view the Alternate Wiring videos
at honeywellhome.com/wifi-
thermostat
Important! C wire is required
and is the primary power source
for your thermostat. Without a
C wire, your thermostat will not
power up.
If you have an older thermostat with
a sealed mercury tube, turn to page
2 for proper disposal instructions.
C
Terminal
designation
9
MCR33823
69-2803ES—05