Thermostat−Specific Information - Lennox SignatureS
tat 81M26 Programming And Application Manual

Thermostat−Specific Information
81M26 1 Stage Heat / 1 Stage Cool, Heat Pump without
Auxiliary Heat, or Non−Heat Pump
Table 2. 81M26 LED Indicators
COOL Cooling mode (Y is active)
CHECK 24V signal is present on the L" terminal
HEAT Heating mode (W is active)
Fan Auto
When COOLING, the indoor blower will cycle with calls for
cooling. When HEATING, and with the thermostat set for gas/oil, the indoor
blower (G) does not cycle with a call for Heat. The independent fan control
in the flue will cycle the indoor blower as necessary.
GO TO: MENU > INSTALLER SETTINGS > SYSTEM SETUP > FURNACE > GAS/OIL
When in electric heat, the indoor blower (G) cycles with the call for heat.
GO TO: MENU > INSTALLER SETTINGS > SYSTEM SETUP > FURNACE > ELECTRIC
When the single stage heat pump is activated, the indoor blower cycles
with every call of heating and cooling.
GO TO: MENU > INSTALLER SETTINGS > SYSTEM SETUP > HEAT PUMP
Fan ON
The indoor blower is ON continuously regardless of whether
the heating or cooling equipment is running.
505232 06/07
Table 3. 81M26 Terminal Designations
R 24 Vac power input
C 24 Vac common
Y1 Energized on call for COOL
E/W1 Energized on call for HEAT
G Energized on call for FAN
H Energized on a call for humidification
D De−energized on a call for dehumidification (reverse logic)
O COOL active (always energized when the stat is in COOL mode,
default value is OFF)
B HEAT active (always energized when the stat is in HEAT mode,
default value is ON)
L Illuminates CHECK LED when energized with 24VAC
NOTE − High−temperature PEPI disables W1 when ambient temperature
exceeds 95°F.
Thermostat Off" Mode
H/D terminals are inactive. The O or B terminal is active. This is determined
by the last state of O/B. For example, if the mode goes from heat (B active)
to off, then B will be active in the off mode. Default on power−up is B active.
The G terminal may be active if FAN ON is selected from the menu.
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In this mode, the heating and cooling and