Operation; Setting Fan And System Switches - Honeywell T8400C Installation Instructions Manual

OPERATION

Setting FAN and SYSTEM Switches

Fan and system settings are controlled manually by using
the switches located at the bottom of the thermostat case.
See Fig. 10.
TEMPERATURE DISPLAY
S e t
R o o m
FAN SWITCH
Fig. 10. Digital display and
Fan and System switches.
FAN Switch
Fan switch settings are:
Auto: Normal setting for most homes. In cooling, the
fan starts and stops with the cooling equipment. In
heating, the fan is controlled directly by the heating
equipment and may start a few minutes after the
heating equipment turns on (for most systems).
When using an electric heat thermostat, the fan
starts and stops with the heating equipment.
On: The fan runs continuously. Use for improved air
circulation and air quality.
Slide the FAN switch in the bottom left corner of the
thermostat to select the desired fan setting.
SYSTEM Switch
System switch settings control thermostat operation as
follows:
Cool: The thermostat controls the cooling system.
Off: Both heating and cooling are off.
Heat: The thermostat controls the heating system.
Slide the SYSTEM switch in the bottom right corner of the
thermostat to select the desired system setting.
INCREASE SETTING
DECREASE SETTING
SYSTEM SWITCH
Set Temperature Setpoint
NOTE: Temperature setpoint range is 40° to 99°F (5° to
37°C).
The temperature setpoint and the room temperature are
shown separately on the digital display. The
points to Set when the temperature setpoint is displayed
and to Room when the room temperature is displayed.
Set
To set temperature setpoint:
1. Select Heat or Cool by sliding the SYSTEM switch in
the lower right corner of the thermostat to the
desired mode. See Fig. 10.
2. To display the temperature setpoints on the digital
display, press either the
temperature setpoint is displayed for approximately
five seconds as the indicator points to Set and
flashes.
M14678A
3. To increase the temperature setpoint, press the
key. Each press changes the setpoint one degree;
press and hold to change the setpoint several
degrees.
4. To decrease the temperature setpoint, press the
key. Each press changes the setpoint one degree;
press and hold to change the setpoint several
degrees.
°
Setting F/
NOTE: To save changes to the °F/°C indication and
the heat cycle rate, all seven steps must be
completed.
To set the °F/°C indication and heat cycle rate:
1. If the temperature is displayed in °F, set the
temperature setpoint to 52°F. If the room tempera-
ture is displayed in °C, set the temperature setpoint
to 11°C.
5
T8400C ELECTRONIC THERMOSTAT
INDICATOR
ROOM TEMPERATURE
Room
SETPOINT TEMPERATURE
or
M14680
M14681
M14682
°
C Indication and Heat Cycle Rate
M14683
indicator
M14679
key once. The
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