Honeywell RTH9580 User Manual page 7

Installing your thermostat
Important!
The Wi-Fi 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.
Check the video section at wifithermostat.com
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 at getconnected.honeywell.com/me
Wiring
conventional
For
conditioner), see page 5. See "Glossary" on page 33 for further definition.
For a heat pump
definition.
Wiring (Conventional System)
6A Wire the Wi-Fi 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 Straighten wire and gently slide into
terminal hole until it clicks into place.
(If you need to remove a wire, use a
pen tip to press the terminal release
and then pull wire out.)
Note: Refer to the wiring picture you took
in Step 2.
Tip:
To make it easier to slide the wire
into place, use a pen tip to hold down the
terminal release.
heating/cooling systems (natural gas, oil or electric furnace, air
system, see page 6. See "Glossary" on page 33 for further
Note:
The wiring for your
application might be different than
the wiring shown below.
Terminal release
Remove jumper loop ONLY if
you have both R and Rc wires.
Labels don't match?
See alternate wiring keys
on pages 7-8.
5
EXAMPLE WIRING
Yours may look different
MCR34540
69-2715EF—07