Installing your thermostat
6 Mount wallplate for thermostat.
Mount your new wallplate using screws and
anchors included with the thermostat.
If necessary:
Drill 3/16-in holes for drywall.
Drill 7/32-in holes for plaster.
Note:
You may be able to use your existing
wall anchors. Hold the wallplate up to the
existing anchors to check for alignment.
Wallplate
Important!
The thermostat requires a C wire to operate. The C, or common, wire
brings 24 VAC power to the thermostat. Many older mechanical or battery operated
thermostats do not require a C wire. If you don’t have a C wire, try:
• Looking for an unused wire that is pushed into the wall. Connect that wire to C and
check that it is connected to the 24 VAC common at your heating/cooling system.
Note:
Not all heating/cooling systems label the 24 VAC common C. Check your system
manual or contact the manufacturer to find out which terminal is the 24 VAC common.
View the Alternate Wiring videos
Wiring
For
conventional
heating/cooling systems (natural gas, oil or electric furnace, air
conditioner), see page 5. See “Glossary” on page 23 for further definition.
For a
heat pump
system, see page 7. See “Glossary” on page 23 for further
definition.
MCR33857
Wiring (conventional system)
7A Wire the thermostat to your conventional system.
a Starting with the C Wire, match the sticky tag on
the wire to the terminal labels.
You must have a C wire.
b Loosen screw, insert wire on inside edge
of terminal, then tighten screw.
c Verify wire is firmly secured by gently
pulling on wire.
d Repeat steps a–c for all other wires.
e Push any excess wire back into the wall
opening after all wires are installed.
f Continue to page 8.
Labels don’t match?
See alternate
wiring key on pages 6.
W2 G
W
Y R RC
K Y2
C
MCR33878
Y
HEAT PUMP
CONVENTIONAL
AUX/E
G
O/B
Y R RC
K L
C
C
G W
R
Remove metal jumper
only
if you have both
R
and
RC
wires
Note:
The wiring for your
application might be different
from the wiring shown above.
