Heat - Using The Heat Mode - Lennox ComfortSense 3000 Series Operation Manual

HEAT - Using the Heat Mode

Normal Heat Mode
In normal heat mode, both the heat pump and the backup
heat source are used to provide heat. If the thermostat
detects 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.
Enabling Normal Heat Mode
Use the HEAT button to select normal heat mode,
emergency heat mode, or to disable heat modes as desired.
If the thermostat is in OFF or COOL mode, pressing the
Heat button enables Heat mode. This is indicated by HEAT
in the SYSTEM box as shown in figure 4.
Figure 4. Turn Heat ON/OFF
Enabling Emergency Heat Mode
If the thermostat is in heat mode, pressing the Heat button
enables EMG. HEAT mode (see figure 5). If the thermostat
is in normal heat mode when the HEAT button is pressed,
then emergency heat mode is enabled.
Figure 5. Emergency Heat Mode Enabled
Disabling Heat Mode
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.
Figure 6. Heating Mode Disabled
Heating Demand
The thermostat must be in either normal or emergency heat
mode in order to properly control the heating equipment.
In either heat mode, when the actual temperature is lower
than the temperature setpoint (as shown in figure 7), the
thermostat detects a heating demand and activates the
heating equipment to satisfy the demand. Heating operation
is indicated by a flame icon in the SYSTEM box.
Figure 7. Heating Demand
When the actual temperature rises above the temperature
setpoint, the flame icon will disappear. This indicates that
the heating demand has been satisfied and that the heating
equipment has been turned off.
Heat pump operation is locked out for 5 minutes after a
demand has been satisfied. If another heat pump demand
occurs during this 5-minute interval, the flame icon will
flash; however, the heat pump will not run until the 5-minute
delay has elapsed.
NOTE: The heat pump is activated for at least 4 minutes if
no buttons are pressed during the demand interval.
The backup heat source is activated for at least
3 minutes if no buttons are pressed during the
demand interval.
If your system supports 3-stage heating (as does the
L3532H thermostat), you may notice various heating levels
being delivered during a demand.
If a small heat pump heating demand is present, "Lo" is
displayed in the SYSTEM box; if a large heat pump heating
demand is present, "Hi" is displayed (see figure 8).
Figure 8. Large Heat Demand
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