Mount thermostat base
1. Drill holes at pencil-marked
locations (3/16" for drywall,
7/32" for plaster).
2. Use hammer to tap anchors
into holes until flush with
wall.
3. [Optional] Pull wires through
cover plate (if needed to cover
marks left by the old thermostat).
4. Pull wires through thermostat
base, position over anchors,
then insert mounting screws.
Check level if desired, then
tighten screws.
Connect wires
1. Match each labeled wire with same
letter on the terminal block(s).
2. Use a screwdriver to loosen screw
terminals, insert bare wire into
slots, then tighten screws.
3. Push any excess wire back into the
wall opening.
Labels don't match?
If labels do not match letters on
thermostat, see table below.
Existing wires Connect to:
R • RH • 4 • V
Rc
O
B
G • F
W • W1 • H
Y • Y1 • M
C • X • B
English:
Terminal "R"
[1]
Terminal "Rc"
[1]
Terminal "O"
[2]
Terminal "B"
[2]
Terminal "G"
Terminal "W"
Terminal "Y"
Do not use
[3]
Page 1 •
Français :
Cover plate
(optional)
Wiring CT87N
[1]
If wires will be connected to both R and Rc
terminals, remove the metal jumper.
[2] Do not connect both O and B if you have a
heat pump. Connect only the O wire. Wrap B
wire with electrical tape and do not use.
[3] Do not use C, X or B. Wrap bare end of wire
with electrical tape.
Wiring CT87K
• 2-wire heat-only system: Connect one
wire to R terminal, one wire to W terminal.
• 3-wire hot water heat-only system: Connect
wires R to R, W to W, and Y to Y terminals.
3
Page 6 •
Español:
Thermostat
base
CT87N
CT87K
R
W
Y
69-1959EFS—02
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