Lennox International Inc. MERIT 51M32 - Manual (Page 9)

Page 3
Figure 6
Heat Mode Disabled
ROOM
SETPOINT
69
64
FAN
AUTO
SYSTEM
OFF
Heating Demand
The thermostat must be in either normal or emergency
heat mode in order to properly control the heating equip-
ment. When in either heat mode, if the actual temperature is
lower than the temperature setpoint, a heating demand is de-
tected by the thermostat. The thermostat will then activate the
heating equipment to satisfy the demand. Heating operation
is indicated by a flame icon in the SYSTEM box as shown in
figure 7.
Figure 7
Heating Demand
ROOM
72
88
FAN
AUTO
SYSTEM
HEAT
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.
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.
Heat pump operation is locked out for 5 minutes after a de-
mand has been satisfied. If another heat pump demand oc-
curs during this 5−minute interval, the flame icon will flash;
however, the heat pump will not run until the 5−minute delay
has elapsed.
Cooling Control
The COOL button is located behind the small door on the
right-hand side of the thermostat. See figure 3.
Enabling and Disabling Cool Mode
Use the COOL button to enable or disable cool mode as
necessary. If the thermostat is in off mode, cool mode is en-
abled when the COOL button is pressed. This is indicated
by COOL in the SYSTEM box.
If the thermostat is in cool mode, cool mode is disabled
when the COOL button is pressed. This is indicated by OFF
in the SYSTEM box.
Cooling Demand
The thermostat must be in cool mode in order to properly
control the cooling equipment. When in cool mode, if the
room temperature is higher than the temperature setpoint,
a cooling demand is detected by the thermostat.
The thermostat will then activate the cooling equipment to
satisfy the demand. Cooling operation is indicated by a
snowflake icon in the SYSTEM box as shown in figure 8.
When the actual temperature drops below the temperature
setpoint, the snowflake icon will disappear. This indicates
that the cooling demand has been satisfied and that the
cooling equipment has been turned off.
Figure 8
ROOM
79
FAN
AUTO
SYSTEM
COOL
Cooling Demand
NOTE − The cooling equipment is activated for at least 4
minutes if no buttons are pressed during the demand inter-
val. Cooling equipment operation is locked out for 5 min-
utes after a demand has been satisfied. If another cooling
demand occurs during this 5−minute interval, the snowflake
icon will flash; however, the cooling equipment will not run
until the 5−minute delay has elapsed.
Adjusting Temperature Setpoint
The temperature setpoint represents the desired tempera-
ture of the space around the thermostat. The default tem-
perature setpoint is 70°F. To adjust the setpoint, press the
UP or DOWN arrow keys to the right of the display screen.
The existing setpoint will be displayed just below the actual
room temperature as shown in figure 9. Use the UP or
DOWN arrow keys to adjust the setpoint up or down. The
setpoint will increase by 1°F each time the UP key is
pressed. The setpoint will decrease by 1°F each time the
DOWN key is pressed.