Fan − Controlling Fan Operation; Settings − Filter /Maintenance Reminder - Lennox Merit 51M37 Operation Manual

NOTE − This thermostat will NOT automatically switch
from heating to cooling, or vice versa; operator involve-
ment is required. At the change of seasons, or to accomo-
date abnormal seasonal temperature swings, you must
manually select to the opposite conditioning (Heat or Cool)
program.
FAN − Controlling the Fan Operation
Use the FAN button to select either continuous fan mode or
auto fan mode.
To change from continuous to auto fan mode (or vice ver-
sa), press the FAN button. Note whether a fan icon in the
FAN box is present (indicating that the fan is running) or not
(fan not running).
If continuous fan mode is enabled (ON displayed in FAN
box − see figure 13), the fan will run continuously regard-
less of whether the heating or cooling equipment is run-
ning.
Using Fan ON
MO
I0:I0
AM
PM
PROG B
SYSTEM
ROOM
67
°
HEAT
Figure 13
If auto fan mode is selected (AUTO displayed in FAN box −
see figure 14), the fan will only run when the heating or
cooling equipment is running.
Using Fan Auto
MO
I0:36
AM
FAN
PM
PROG B
AUTO
SYSTEM
ROOM
72
COOL
°
Figure 14
SETTINGS − Filter/Maintenance Reminders
The 51M35 thermostat is designed to remind you when the
filter needs changing or when routine maintenance is re-
quired, as (and if) defined, by you. These optional remind-
ers are not enabled until you activate them. To do so, press
the Settings button (shown below the Fan button in figure
14) once or twice for the desired reminder as shown in fig-
ure 15 and as described in table 1.
Heat Cool
FAN
ON
Prog Day/Time
Fan Hold
Settings Enter
Heat Cool
Day/Time
Prog
Fan Hold
Settings Enter
Reminder Settings Display
OFF
The default setting for the reminders is OFF (disabled).
Press Up/Down arrow buttons to select the desired re-
minder intervals.
Filter and Maintenance Reminders
Buttons to
Use Reminder
Settings FILTER
(1st press) (1st press)
then Arrows
to scroll to scroll
selections
Settings MAINT
(2nd press) (2nd press)
then Arrows
to scroll to scroll
selections
Enter
NOTE − The HOME screen will reappear about 15 seconds
after the final arrow button press. OR, press ENTER at any
time to store any changes and exit to the HOME screen.
After either programmed interval has elapsed, the remind-
er will be displayed as shown in figure 16.
MO TU WE TH FR SA SU
I0:i2
AM
PM
PROG A B C D
ROOM
78
°
After the filter has been changed or maintenance per-
formed, reset the reminder by pressing the SETTINGS
button for 4 seconds. The screen will blink for a few mo-
ments to indicate that the timer has been reset.
Page 5
For MAINT,
MAINT
press Settings
FILTER button 2 times
For FILTER,
press Settings
button 1 time
Figure 15
Table 1
Available Settings and
How to Use
Total fan run time expressed in
months (Off, 1, 3, 6, 12); for months (Off 1 3 6 12); for
example, if fan runs 12 hours a
day, 1 month reminder displays day 1 month reminder displays
in 2 calendar months.
Elapsed chronological time in
months (Off, 6, 12). Use this, months (Off 6 12) Use this
for example, to remind yourself
when to perform routine checks when to perform routine checks
or when to call a technician for
perodic preventive perodic preventive
maintenance.
Stores settings.
Reminders
MAINT
FILTER
SERVICE
FAN
ON
AUTO
HOLD
SYSTEM
COOL
OFF
HEAT
Figure 16
51M35 SERIES 5/2