Step 2. Remove Old Thermostat; Step 3. Special Installations - Honeywell THE DIGITAL ROUND CT8775A Owner's Manual

STEP 2. REMOVE OLD THERMOSTAT

Test your heating and cooling systems to make sure they work properly. If either system does not work, contact
your local heating/air-conditioning dealer. To avoid compressor damage, do not operate the cooling system when
outdoor temperature is below 50°F (10°C).
Turn off power to the system at the furnace or the fuse/circuit breaker panel.
Carefully unpack your new thermostat and decorator cover plate. Save package of screws, instructions, and
receipt.
Remove the cover from the old thermostat. If the cover does not snap off when pulled firmly from the top or bottom,
check for a screw or screws that may be used to lock on the cover.
Loosen the screw or screws (if present) holding the thermostat to the wallplate and lift the thermostat away. Do not
disconnect wires.

STEP 3. SPECIAL INSTALLATIONS

Read this section if you are replacing:
• A thermostat that has wires connected to C or C1 terminals.
• A thermostat that is connected to six or more wires.
• A thermostat that is connected to three wires on a warm air heating only system.
• A thermostat that is connected to three wires on a zoned hot water heating system.
NOTE: If none of the special installations apply to your particular application, please skip to Step 4.
Replacing a thermostat that has wires connected to C or C1 terminals
If you are replacing a thermostat that has one or two wires connected to C or C1 terminals, do not allow them to touch,
or you can damage the transformer. Wrap the wires separately using electrical tape. Place the wires where they will
not interfere with the operation of the new thermostat. Continue with the installation at Step 4.
Replacing a thermostat that is connected to six or more wires
If you are replacing a thermostat that is connected to six or more wires (excluding wires connected to C or C1
terminals), you may have a multistage heat pump or other multistage system. If you have either one of these systems,
return the product to the place of purchase. This thermostat is not compatible with these systems. For information
about which thermostats will work with your system, call Honeywell Customer Care, at 1-800-468-1502.
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