Remove Old Thermostat - Honeywell CT41A Instructions D'installation

3

REMOVE OLD THERMOSTAT

Begin by turning off power to the heating/air
conditioning system at the main fuse panel. Most
residential systems have a separate switch box or circuit
breaker for disconnecting power to the furnace.
Remove cover of old thermostat—cover normally
snaps off when pulled firmly from the bottom. If it
resists, check for a screw that locks on the cover.
Before removing the old thermostat from the wall,
look at it carefully to locate the heat anticipator
adjustment mechanism. (See illustration in step 2 to help
you recognize the heat anticipator.) Make a note
here of that anticipator setting for future
reference. The heat anticipator pointer, if adjustable, will
be set at one of a series of numbers representing the
(electrical) current rating of the primary control of your
system in amperes. The number will range from 0.18 to
1.0. If no heat anticipator/indication is showing, do not be
concerned; move on to the next step.
4
WIRE AND MOUNT NEW THERMOSTAT
Connect wires from the wall to matching terminals
on the back of the thermostat. Tighten the screws.
NOTE: If terminal designations on old thermostat do not
match those on new thermostat, refer to chart below.
Old Thermostat
Terminal Marked
G or F
Y or C
W or H
RC, V, VC or B
RH, M, VR, 4, A or R
Push excess wire back into the wall and plug the
hole with nonflammable insulation to prevent drafts
from affecting thermostat operation.
Grasp the thermostat cover at the top and bottom
with one hand. Pull outward on the bottom edge of
the thermostat cover until it snaps free of the thermostat
base.
Fasten thermostat to wall or vertical outlet box with a
screw through the top mounting hole. See step 2
illustration for hole location.
Place a bubble level or plumb line against the
thermostat to find the level position. Start a screw
in the center of the bottom mounting hole. Move the
temperature setting lever, if necessary, to uncover the
mounting hole.
Recheck for level positioning, and firmly tighten both
mounting screws.
69-0848B
New Thermostat
Function Terminal Marked
Fan G
Cooling Y
Heating W
Power You have a 5-wire
system, and
cannot use this
thermostat; we
recommend a
CT87B.
Power R
Loosen screws holding thermostat base to subbase
or wall, and lift away.
Disconnect wires from old thermostat or subbase. If
your thermostat has more than two wires, as you
disconnect each wire, tape the end and label it with the
letter of the terminal designation to make reconnection to
the new thermostat easier. Take care that these wires do
not fall back into the wall opening.
Keep the old thermostat for reference until your new
thermostat is functioning smoothly.
W
TERMINAL SCREWS
2
M3775
R
G
Y
M8067A
BUBBLE LEVEL
PLUMB
LINE
PLUMB
BOB OR
WEIGHT
M3774