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3 69-2040EFS—01

Wiring CT50/CT53/CT54

• 2-wire heat-only system: Connect one
wire to R terminal, one wire to W terminal.
M23791

Wiring CT51/CT55

[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.
M23792
1. Drillholesatpencil-marked
locations(3/16”holesfor
drywall,7/32”holesfor
plaster).
2. Use hammer to tap anchors
intoholesuntilushwithwall.
3. Pullwiresthroughthermostat
base and insert screws.
Check level if desired, then
tighten screws.
Mount thermostat base
1. Matcheachlabeledwirewithsame
letter on terminal.
2. Use a screwdriver to loosen screw
terminals, insert bare wires beneath
screws, 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 Terminal “R” [1]
Rc Terminal “Rc” [1]
O Terminal “O” [2]
B Terminal “B” [2]
G•F Terminal “G”
W•W1•H Terminal “W”
Y •Y1•M Terminal “Y”
C•X •B Do not use [3]
CT51/CT55
CT50/CT53/CT54
Connect wires