CT3451 PROGRAMMABLE THERMOSTAT
69-1620—1 6
Fig. 13. Installing batteries.
❑Restore power to the heating/cooling system.
8 CUSTOMIZE YOUR THERMOSTAT
Your Honeywell thermostat comes preset to the most
commonly used settings:
—Temperature (°F).
—Gas or oil forced air furnace.
—Aggressive algorithm control.
You can change these settings using the instructions that
follow. To exit at any time, press the ▲ key until End
displays.

Setting °F/°C Indication, Heat Cycle Rate,

Heating/Cooling Temperature Control

The following instructions provide information to change
the heating cycle rate to match the heating equipment
and to choose either the Fahrenheit (°F) or Celsius (°C)
display.
NOTE: All four ste ps must be completed to save
changes to the °F/°C indication and the heat
cycle rate.
❑Enter Installer Setup.
— Use ▼ or ▲ keys to set the temperature setpoint
to 52°F (11°C).
— Press ▼ and ▲ keys simultaneously for more
than two seconds to enter Installer Setup.
— Release the keys to display the three-digit soft-
ware revision code. (Information displayed varies
by model).
— Press the ▲ key. FC (factory configuration) dis-
plays. (A typical example is shown, but informa-
tion displayed varies by model. This information
is for factory use only.)
❑Setting °C or °F.
— Press the ▲ key again to display the current
setting.
— Press the ▼ key to change the °C or °F indication.
❑Setting Heat Cycle Rate (see Table 2 for the cycle rate
options and equipment).
— Press the ▲ key to display the current heat cycle
rate setting of 1, 3, 4, 5, 9, or 12 cph.
— If the desired cycle rate is displayed, press the ▲
key to display heating and cooling algorithm
default.
— To change the heat cycle rate, press the ▼ key
until your choice of 1, 3, 4, 5, 6, 9, or 12 is dis-
played.
— Press the ▲ key to display the heating and
cooling temperature control algorithm configura-
tion default.
— Press the ▼ key to change the heating and cool-
ing control algorithm to C1 or C3.
C1 = Standard control algorithm.
C3 = Aggressive control algorithm (Default. Can
cause overshooting.)
M20514
SYSTEM
Cool Off Heat
Auto On
FAN
Hold
Select
TUE
PM
AA BATTERIES (3)
M12582
A
SET
HT.
M1258
3
M12584
A
M12589
A
M12588
A
M1469
1