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T8424D ELECTRONIC MULTISTAGE THERMOSTAT
TEMPERATURE DISPLAY
FAN SWITCH
Fig. 7. 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
.
Room
Set
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. 7.
2. To display the temperature setpoint on the digital
display, press either the
temperature setpoint is displayed for approxi-
mately five seconds as the indicator points to Set
and flashes.
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.
69-1386-1
INCREASE SETTING
DECREASE SETTING
SYSTEM SWITCH
indicator
INDICATOR
ROOM TEMPERATURE
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or
key once. The
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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 and the
heat cycle rate, all seven steps must be com-
pleted.
To set the °F/°C indication and heat cycle rate:
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
11°C.
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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.
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
NOTE: In Optional System Checkout for multistage
models, pressing the
stage output. (The second press of the
turns on the second stage output.)
NOTE: In installer setup mode only, each press of the
the
keys are released, these two-digit codes are no
longer displayed.
4
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keys simultaneously for more than
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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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key turns on the first
key momentarily displays 01. Each press of
key momentarily displays 02. When the
key can be used to
turns it on.
key
turns it on.
key
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