Lennox SignatureS
tat 81M26 User Manual

SignatureStat t Thermostat
Page 21
Installing Remote Outdoor Sensor
Install the remote outdoor sensor on a northern wall of the home, away from
direct sunlight or other heat sources that may affect its sensitivity.
IMPORTANT
The outdoor sensor must be connected with twisted pair wire
(84X49 [1000’ roll] or X3790 [500’ roll]). For operating a system with
a Humiditrol
®
accessory, the remote sensor MUST be installed.
Display Lights
The display lights indicate HVAC system operation.
S HEAT or COOL light will be illuminated with a call for heating or cooling
(81M26 and 81M27 models).
S AUX light indicates the second stage of heating − W2 is active (81M28
model only).
S EMER light indicates that the emergency heat is enabled in HEAT/
COOL menu, regardless of heat demand (81M28 model only). Emer-
gency heat is activated via the E/W1 terminal.
S CHECK light comes on when a 24V signal is present on the L" termi-
nal. This indicates that the equipment requires service by a qualified
technician (all models).
Memory Protection
The thermostat stores all the information concerning its programming
(state, mode, program information, last temperature measured) in a non-
volatile memory.
This function avoids the loss of the state of the thermostat when a power−
down occurs. The only thing that might be lost is the time. A super−cap pro-
vides 2 hours of power reserve (for power outages). When a power down
occurs (due to a power outage) the thermostat is able to switch off all relays.
The O and B relay will maintain their last state.
EPA ENERGYSTAR
®
Recommended Setpoints
EPA ENERGYSTAR
®
recommended setpoints for heating and cooling can
help the household save energy.
The following time and temperatures are preprogrammed into the control to
conform to Energy Star requirements.
Table 1. ENERGYSTAR
®
Setpoints
Time Winter Heating Summer Cooling
Morning 70°F (21°C) 78°F (25°C)
Day 62°F (17°C) 85°F (29°C)
Evening 70°F (21C) 78°F (25°C)
Night 62°F (17°C) 82°F (28°C)
NOTE − Humidification and dehumidification are not part of the ENERGYS-
TAR
®
program. A higher utility bill may occur when not using the setpoints
in table 1.
Resetting Program to Factory Conditions
To reset the SignatureStatt thermostat to factory conditions, press the UP
button and the LEFT button at the same time. Hold for 8 seconds. The time
of day will display 12:00 indicating a reset has occurred or until LENNOX 
or the software version is shown on LCD.
NOTE − This will erase all programming and return the thermostat to the fac-
tory conditions, including the installer settings. Use this only as a last resort.

Lennox SignatureS
tat 81M26 Specifications

General

Brand	Lennox
Model	SignatureS tat 81M26
Category	Thermostat
Language	English