Heating Control - Lennox MERIT 51M32 Operation Manual

Display − Home Screen
70
ROOM
Figure 2
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 will turn on each time a key is
pressed. The backlight will turn 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.
Additional Thermostat Buttons
Figure 3
Enabling and Disabling Heat Mode
Use the HEAT button to enable or disable heat mode as de-
sired. If the thermostat is in off mode, heat mode is enabled
when the HEAT button is pressed. This is indicated by
HEAT in the SYSTEM box as shown in figure 4.
FAN
AUTO
SYSTEM
HEAT
Page 2
Heat Mode Enabled
69
ROOM
64
SETPOINT
Figure 4
If the thermostat is in heat mode, heat mode is disabled
when the HEAT button is pressed. This is indicated by OFF
in the SYSTEM box as shown in figure 5.
Heat Mode Disabled
69
ROOM
64
SETPOINT
Figure 5
Heating Demand
The thermostat must be in heat mode in order to properly
control the heating equipment. When in heat mode, if the
actual temperature is lower than the temperature setpoint, a
heating demand is detected by the thermostat. The thermo-
stat will then activate the heating equipment to satisfy the de-
mand. Heating operation is indicated by a flame icon in the
SYSTEM box as shown in figure 6.
FAN
AUTO
SYSTEM
HEAT
FAN
AUTO
SYSTEM
OFF