Heating Control - Lennox ComfortSense L3021H Operation Manual

70
ROOM
Figure 2. Display − Home Screen
Figure 2 illustrates the HOME screen. Note that an indoor
room temperature of 70°F is initially displayed. After about
1 minute of warm−up time, the actual room temperature will
be displayed. HEAT mode is the system default (as indi-
cated in the SYSTEM box at lower right).
A pale blue display backlight turns on each time a key is
pressed; then off 8 seconds after the last key is pressed.

Heating Control

The HEAT button is located behind the small door on the
right−hand side of the thermostat. See figure 3.
Figure 3. Additional Thermostat Buttons
Normal Heat Mode
In normal heat mode, both the heat pump and the backup
heat source are used to provide heat. If the thermostat de-
tects that the heat pump is not able to provide enough heat
(as may be the case in very cold weather), then the backup
heat source is activated.
Emergency Heat Mode
In emergency heat mode, only the backup heat source
provides heat the heat pump is disabled. The backup
heat source is activated only when there is a heat demand.
506078−01 02/08
Enabling and Disabling Heat Mode
Use the HEAT button to select normal heat mode, emer-
gency heat mode, or to disable heat modes as desired. If
the thermostat is in off mode, normal heat mode is enabled
FAN
when the HEAT button is pressed. This is indicated by
HEAT in the SYSTEM box as shown in figure 4.
AUTO
SYSTEM
HEAT
If the thermostat is in normal heat mode when the HEAT
button is pressed, then emergency heat mode is enabled.
This is indicated by EMG. HEAT in the SYSTEM box as
shown in figure 5.
If the thermostat is in emergency heat mode when the
HEAT button is pressed, then heat modes are disabled.
This is indicated by OFF in the SYSTEM box as shown in
figure 6.
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SETPOINT
Figure 4. Normal Heat Mode Enabled
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64
SETPOINT
Figure 5. Emergency Heat Mode Enabled
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SETPOINT
Figure 6. Heat Mode Disabled
FAN
AUTO
SYSTEM
HEAT
FAN
AUTO
SYSTEM
EMG.
HEAT
FAN
AUTO
SYSTEM
OFF