Lennox Merit 51M37 Operation Manual page 29

HEAT − Using the Heat Mode
Enabling and Disabling Heat Mode
The thermostat must be in the heat mode to control the
heating equipment. Press the HEAT button to enable or
disable HEAT mode. If the thermostat is in cool or off
mode, pressing the HEAT button enables the heat mode
(indicated by HEAT in the lower right corner − see figure 4).
Turn Heat ON/OFF
5:30
82
70
66
Figure 4
If the thermostat is in heat mode, heat mode is disabled
when the HEAT button is pressed. This is indicated by OFF
near the right side of the display as shown in figure 5.
Heat/Cool Mode Disabled
75
ROOM
Figure 5
Heating Demand
Set the thermostat to heat mode to control the heating
equipment. Then, if the room temperature is lower than the
temperature setpoint, as shown in figure 6, the thermostat
detects a heating demand and will activate the heating
equipment to satisfy the demand.
Heating Demand
72
ROOM
Figure 6
Heating operation is indicated by a flame icon in the lower
right corner. 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.
If your system supports 2−stage heating (as does the
51M39 thermostat), you may notice various heating levels
being delivered during a demand.
NOTE − Heating equipment is activated for at least 3 min-
utes if no buttons are pressed during the demand interval.
Heat Cool
Prog Auto
Copy Day/Time
Fan Hold
(DOOR
OPEN)
Settings Enter
(Outside)
OFF
°
75
HEAT SETPOINT
°
°
75
HEAT SETPOINT
°
HEAT
COOL − Using the Cool Mode
Enabling and Disabling Cool Mode
Use the COOL button to enable or disable cool mode as
desired. If the thermostat is in heat or off mode, cool mode
is enabled when the COOL button is pressed. This is indi-
cated by COOL on the right side of the display (see figure
8).
Turn Cool ON/OFF
i0:30
70
75
66
If the thermostat is in cool mode, pressing the COOL but-
ton disables cool mode (indicated by OFF in the SYSTEM
box − see figure 5).
Cooling Demand
Set the thermostat to cool mode to control the cooling
equipment. Then, if the room temperature is higher than
the temperature setpoint, as shown in figure 7, the thermo-
stat detects a cooling demand and will activate the cooling
equipment to satisfy the demand.
Cooling operation is indicated by flashing snowflake"
icons on the right side of the display. When the actual tem-
perature drops below the temperature setpoint, the snow-
flake icons will disappear. This indicates that the cooling
demand has been satisfied and that the cooling equipment
has been turned off.
If your system supports 2−stage cooling (as does the
51M39 thermostat), you may notice various cooling levels
being delivered during a demand. Also, if a small cooling
demand is present, "Lo" will be displayed in the SYSTEM
box. However, if a large cooling demand is present, "Hi" will
be displayed in the lower right corner (shown in figure 8).
Cooling Demand
FAN
AUTO
ROOM
80
Page 3
Heat Cool
Prog Auto
Copy Day/Time
Fan Hold
Settings Enter
(Outside)
Figure 7
76
COOL SETPOINT
°
COOL
68
HEAT SETPOINT
°
°
Figure 8
51M39 SERIES 5/2
(DOOR
OPEN)
Hi
Lo