Step 2 Remove Old Thermostat - Honeywell CT3400 Programming And Installation Instructions

STEP 2 Remove Old Thermostat
■
Test to make certain that your heating and
cooling systems are working properly. If either
does not work, contact your local heating/air
conditioning dealer. To avoid compressor dam-
age, do not operate the cooling system when
outdoor temperature is below 50° F [10° C].
■
Turn off power to system at the furnace, or
at the fuse/circuit breaker panel.
■
Carefully unpack your new thermostat and
wallplate; save package of screws, instructions
and receipt.
■
Remove the cover from the old thermostat. If
it does not snap off when pulled firmly from the
bottom, check for a screw used to lock on the
cover.
■
Loosen screws holding thermostat to sub-
base, wallplate or wall, and lift away.
■
Disconnect wires from old thermostat or
subbase. As you disconnect each wire, use
masking tape to label it with the old terminal
designation. If there are only two wires, they do
not need to be labeled. Wrap wires around
pencil to keep them
from falling back into
the wall, as shown.
One or two extra
wires?
If you are replacing a
Honeywell Chronotherm
find one or two wires that go to the clock termi-
nals on the Chronotherm thermostat wiring
wallplate. Do not allow them to touch, or you can
damage your transformer. Disconnect the wires
4
WIRES THROUGH
WALL OPENING
M5136
®
Thermostat, you may
69-0733B—1