Honeywell RTH9585 - Installing your thermostat; Switch OFF power to your heating;cooling system; Remove old thermostat faceplate and leave wires connected

3 69-2715EF—07
Installing your thermostat
You might need the following tools to install this thermostat:
• No. 2 Phillips screwdriver
• Pen
• Pencil
• Level (optional)
• Drill and bits (3/16” for drywall,
7/32” for plaster) (optional)
• Hammer (optional)
• Electrical tape (optional)
1 Switch OFF power to your
heating/cooling system.
Important! To protect your
equipment, switch OFF the power
to your heating/cooling system
at the breaker box or the system
switch.
or
M31535
Circuit
breaker
box
Heating/cooling
system power
switch
C
M33823A
If you have an older thermostat
with a sealed mercury tube, turn
to page ii for proper disposal
instructions.
Terminal
designation
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
wifithermostat.com/videos
or reference the C-wire
addendum in the box.
Important! C wire is required
and is the power source for your
thermostat. Without a C wire, your
thermostat will not power up.
Note: You will need a
picture of your wire
connections to wire the
new thermostat.