Installing Your Thermostat - Honeywell RTH8580ZW User Manual

Installing your thermostat

You might need the following tools to install this thermostat:
• No. 2 Phillips screwdriver
• Small pocket screwdriver
• Pencil
• Level (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.
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, call 1-800-468-1502
for wiring assistance.
Important!
C wire is required and
is the primary power source for
your thermostat. Without a C wire,
your thermostat will not power up.
• Drill and bits (3/16" for drywall,
7/32" for plaster) (optional)
• Hammer (optional)
• Electrical tape (optional)
If you have an older thermostat with a
sealed mercury tube, turn to page ii
for proper disposal instructions.
C
Terminal
designation
3
or
Circuit Heating/cooling
breaker system power
box
M31535
switch
MCR33823
33-00131ES—01