System Switch - Honeywell T8400C1099 Installation Instructions Manual

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.
TEMPERATURE DISPLAY
FAN SWITCH
Fig. 12. Digital display and system
switches (FAN and SYSTEM).
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 Room
SETPOINT TEMPERATURE
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. 12.
2. To display the temperature setpoint on the digital
display, press either the
perature setpoint is displayed for approximately
five seconds as the indicator points to Set and
flashes.
INCREASE SETTING
DECREASE SETTING
SYSTEM SWITCH
indicator
INDICATOR
ROOM TEMPERATURE
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or key once. The tem-
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T8400C1099, T8401C1031 ELECTRONIC THERMOSTATS
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/°C Indication and Heat Cycle Rate
NOTE: To save changes to the °F/°C indication, the
heat cycle rate and the C3/C1 temperature
control, tap the
setup.
To set the °F/°C indication, the heat cycle rate and the
C3/C1 temperature control:
1. If the temperature is displayed in °F, set the tem-
perature setpoint to 52°F. If the room temperature
is displayed in °C, set the temperature setpoint to
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11°C.
OPTIONAL SYSTEM CHECKOUT
When in steps 2 and 3 only, the
turn heat or cool outputs on and off. Change the
SYSTEM switch setting to test heat or cool outputs. No
action takes place If the system switch is in the Off
position.
Examples: System setting at HEAT: If heat is on, the
2. Press the
one second to light all segments on display and to
enter installer setup mode. When the keys are
released, a two-digit software revision code is dis-
played.
5
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key until exiting the installer
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key turns it off; if heat is off,
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System setting at COOL: If cool is on,
turns it off; if cool is off,
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keys simultaneously for more than
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key can be used to
turns it on.
key
turns it on.
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