Honeywell CT87A User Manual 2
1
CT87A,B,J Round® Thermostat
LOW VOLTAGE (15 TO 30 VAC),
THERMOSTAT AND MOUNTING HARDWARE
Installation Instructions
Verify that you have the correct thermostat
Using the compatibility chart
below, verify that you purchased
the correct CT87Thermostat for
your heating/cooling system. If
you are unsure which model is
right for your system, visit
www.honeywell.com/
yourhome or call Honeywell
Customer Care at
1-800-468-1502.
Compatible with:
Heating/Cooling system
Heating only: Gas or oil fueled warm air, steam, or hot
water heat
Cooling only: Electric air conditioning Yes* Yes Yes
Heating and cooling: Gas or oil fueled warm air,
steam, or hot water heat with electric air conditioning
Single stage heat pump: Outdoor heating/cooling unit
(compressor) with no auxiliary or backup heat.
Electric heat furnace with or without cooling: No No
Electric baseboard: Electric heating strips located just
above the floor, usually 120-240 volts
Multistage: A conventional system with more than one
stage, or an outdoor heating/cooling unit (compressor)
with auxiliary or backup heat.
CT87A CT87B CT87J
Yes Yes No
No
No No Yes
No No No
No No No
Yes No
Yes
* CT87A is compatible with 2-wire cooling-only systems.
® U.S. Registered Trademark
Copyright © 2002 Honeywell
All Rights Reserved
69-0274-6
CT87A,B,J ROUND® THERMOSTAT
2
3
Prepare for installation
1. Carefully unpack your new thermostat; rough handling may affect its
accuracy. Save your receipt and identify the following parts:
• CT87 Thermostat
• Screws: two 1-in. sheet metal screws, two 1/2-in. binding head
screws, and two 1/4-in. round head screws
• Wallplate (CT87A) or subbase (CT87B, CT87J)
• Cover ring (select models only). Necessary if installing on an
outlet box. Optional if installing directly on the wall; can be used to
hide wall marks.
• These Installation Instructions and the Installation Quick Guide.
• Wiring labels
2. Gather these tools:
Required Tools Optional Tools
• Flat blade
screwdriver
• Spirit level
• Hand or power drill with 1/16-in. drill bit
• Wire cutter/stripper or sharp knife
• Pencil
Remove the old thermostat
1. Turn off power to the heating/cooling system at the main fuse/circuit
breaker panel.
2. Remove the cover of your old thermostat. You may need to unscrew
the cover if it is locked on.
3. Locate the heat anticipator adjustment scale and lever on the old
thermostat (Fig. 1).
Fig. 1. Mercury switch location.
MERCURY
SWITCH
OLD THERMOSTAT
ANTICIPATOR
SCALE
LEVER
TYPICAL LOCATION OF A
MERCURY SWITCH IN
A THERMOSTAT
In the box below, record the
number that the adjustment lever
points to. This is the current (amp)
rating of your heating system.
Current setting:
If you cannot find the heat
anticipator setting on the old
thermostat, you can use a
standard setting for your type of
system when you reach Step 8 of
M20206
this installation.
4. Unscrew and remove the old thermostat wallplate from the wall, but
do not disconnect the wires.
69-0274-6 2
CT87A,B,J ROUND® THERMOSTAT
H
4
5. Label the wires using the wiring
labels that came with the CT87.
Fig. 2. Labeling wires.
Identify each wire using the letter
of the terminal on the old thermo-
stat (Fig. 2). Do not label the wires
by color.
6. Disconnect the wires from the old
thermostat and wrap them around
a pencil to keep them from
falling
back into the wall (Fig. 3).
Fig. 3. Wrapping wires.
WIRES THROUG
MERCURY NOTICE
WALL OPENING
If this thermostat is replacing a
control that contains mercury in a
sealed tube, do not place your old
control in the trash. Contact your
local waste management authority
for instructions regarding recycling and the proper disposal of this
control, or of an old control containing mercury in a sealed tube.
Install the cover ring and wallplate or subbase
If installing on the wall
Refer to Fig. 4 as you work.
M19086
M20133
Fig. 4. Installing wallplate/subbase on the wall (wallplate shown).
COVER RING
WALLPLATE
THERMOSTAT
NO. 4 X 1 INCH
SHEET METAL SCREWS (2)
3 69-0274-6
WIRING OPENING
M20188
CT87A,B,J ROUND® THERMOSTAT
7
1
R
H
S
1. If using the cover ring: Position the cover ring against the wall so
that the arrow in the middle of the cover ring is pointing up.
2. Position the wallplate or subbase.
• If using cover ring: Place the wallplate/subbase over the cover
ring. Rotate the wallplate/subbase until the wiring openings are
aligned and the two screw holes on the left and right side of the
wallplate/subbase align with the screw holes on the cover ring.
You will be inserting screws through these holes into the wall.
• If attaching wallplate directly to the wall: Position so that the
UP indicator on the wallplate is on top.
• If attaching subbase directly to the wall: Position so that the
fan and heating/cooling switches are on the top.
3. Use a pencil to mark the center of the screw holes on the left and
right sides of the wallplate or subbase.
4. Remove the wallplate/subbase and cover ring, and drill two 1/16-in.
holes at the locations you marked.
5. Reposition the cover ring (if used) and wallplate/subbase over the
holes, pull the wires through the wiring opening, and loosely insert
the two 1-in. screws into the drilled holes.
If installing on an outlet box
Refer to Fig. 5 as you work.
Fig. 5. Installing wallplate/subbase on an outlet box (subbase shown).
69-0274-6 4
1/2 IN. BINDING
HEAD SCREW (2)
1
2
COVER RING
SUBBASE
/4 IN.
OUND
EAD
CREW (2)
1
THE TWO INNER HOLES ARE USED WITH WALLPLATE.
2
IF OUTLET BOX IS HORIZONTAL, MOUNT COVER RING IN
POSITION SHOWN, BUT FASTEN WITH SCREWS THROUGH "A".
OUTLET BOX
THERMOSTAT
WIRING HOLE
A
M2018
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