Lennox MERIT 51M32 Operation Manual page 13

Service Reminder
The SERVICE indicator is displayed only under the follow-
ing conditions:
S
if the thermostat Y1 terminal has been activated
with 24VAC for at least 5 minutes, AND the L
terminal is shorted to the R terminal;
OR
S
if the thermostat Y1 terminal has been activated
with 24VAC for at least 5 minutes, AND the L
terminal is shorted to the C terminal.
Power Loss/Recovery
Thermostat memory is retained for a minimum of 24 hours
during a power loss (includes retention of programmed
temperature setpoint, heat/cool and fan mode settings, fil-
ter reminder status, and equipment protection timers). Af-
ter 24 hours of power loss, programmed settings will be lost
and replaced with default settings.
IMPORTANT
Power must be applied for at least six consecutive
hours prior to a power loss in order for memory to be
retained for the specified time.
LCD Backlight
Activated for 8 seconds when any key is pressed.
NOTE − During an electrical storm or similar disturbance,
the backlight may activate for a few seconds. This is normal
and will no longer occur after the electrical disturbance has
passed.
Thermostat Operating Conditions
35°F to 105°F, 5% to 90% RH
Thermostat Storage Conditions
−40°F to 185°F, 5% to 95% RH
Thermostat Output Table
Table 3 (see page 8) provides details of the 51M33 ther-
mostat output states for various input conditions.
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