Lennox S40 User manual

508223-01 10/2022
Copyright 2022© Lennox Industries Inc.
Dallas, Texas, USA
Dallas Home
Temp Status My Home
Heat to Cool to
68 75
72
Feels Like
60%
Away Weather
TM
TM
Lennox®S40 Smart Thermostat
User Guide

2
Table of Contents
Features............................................... 4
Display Features......................................... 4
External Component Locations ................ 4
Reboot Button, Micro USB Connection
and Built-in Sensors................................... 4
Comfort Features........................................ 4
Optional Accessories ................................. 5
Downloading Lennox Smart
Applications........................................ 5
Lennox Smart Technician App .................. 5
Lennox Smart Thermostat App ................. 5
Connecting the Thermostat to the
Home Wi-Fi.......................................... 6
Multiple S40 Thermostats in the Home .... 6
Wi-Fi Considerations.................................. 6
Supported Wi-Fi Network Types................ 6
Connecting to a Visible Home Wi-Fi
Access Point ............................................... 6
Connecting to a Hidden Wi-Fi Access
Point............................................................. 6
Electromagnetic Interference Causing
Poor Connectivity....................................... 7
Wi-Fi Terminology....................................... 7
Received Signal Strength Indicator
(RSSI)........................................................... 7
Creating an Account ......................... 8
Using the Thermostat................................. 8
Using the Lennox Smart Thermostat
App............................................................... 8
Home Screen Details.........................11
Temperature Settings............................... 12
Current Outdoor Temperature and
Weather Forecast...................................... 12
Time and Date Display ............................. 12
Humidity Display ...................................... 12
Away .......................................................... 12
Temp .......................................................... 12
Status......................................................... 12
My Home.................................................... 12
Thermostats and Zones...................................13
Lennox Smart Room Sensor ........................... 13
Lennox Smart Air Quality Monitor....................13
Lennox Wireless Extender (BLE) ....................13
PureAir S .........................................................13
Home and Status Screens Icon
Descriptions...................................... 14
Menu .................................................. 18
General ...................................................... 18
Notications.....................................................18
User Account ...................................................18
Display Settings...............................................18
Lennox Dealer Support Access .......................19
System....................................................... 19
Mode................................................................19
Schedule (Single Zone)...................................19
Schedules (Zoning) .........................................21
Fan (On, Auto and Circulate)...........................21
Settings ............................................. 22
System Info ............................................... 22
Settings .................................................... 22
Wi-Fi ................................................................22
Away................................................................22
Manual Away .........................................................22
Smart Away ...........................................................23
Current Temperature .......................................24
Feels Like.............................................................24
Using Smart Room Sensors..................................24
Fan ..................................................................25
Allergen Defender .................................................25
Circulation Timer Adjustment.................................25
Heat / Cool.......................................................25
Perfect Temperature..............................................25
Wider Set-Point Range..........................................25
Auxiliary Heat ........................................................25
Safety Protection...................................................25
Humidity...........................................................25
Humidity Control....................................................26
Humidication Control Center..........................26
Dehumidication Control Center ...........................26
No Dehumidication Accessory Installed ..............26
Humidify + Dehumidify Settings ............................26
Dehumidication Accessory Installed....................28
Smart Zoning System......................................28
Heating / Cooling Changeover ..............................28
Cooling Operation ................................................28
Heating Operation ................................................28
Notications.....................................................29
Peak Monitoring...............................................29
Enable Peak Monitoring ........................................29
Enroll in Peak Monitoring ......................................29
Peak Monitoring Settings ......................................29
Canceling Peak Monitoring Event .........................30
Cancel Enrollment .................................................30
Equipment .......................................................30
PureAir™ S...........................................................30

3
Ventilation..............................................................30
Advanced Settings...........................................31
View Support Service Control Center....................31
Restart ..................................................................31
Unregister System...........................................31
Lennox Smart Devices..................... 32
Lennox Smart Room Sensor .................. 32
Adding and Removing Smart Room Sensor....32
View and Understanding the Smart
Room Sensor Detail Screen............................32
Room Averaging using Occupancy Detection .32
Occupancy Sensor Setting..............................32
Lennox Wireless Extender....................... 33
Adding and Removing the Lennox
Wireless Extender ...........................................33
View and Understanding the Wireless
Extender Detail Screen....................................33
Lennox Smart Air Quality Monitor .......... 33
Status Indicator Light Color Descriptions ........ 33
Adding and Removing the Smart Air
Quality Monitor (SAQM) .................................. 33
How the Smart Air Quality Monitor Works .......34
Side Switch......................................................34
Denition of Contaminants .............................. 34
Smart Air Quality Details Screen .....................35
Indoor Level of Air Cleanliness Setting............ 35
View Details and Postpone Cleaning Air .........36
Third-Party Integration..................... 36
Amazon Alexa ........................................... 36
Changing to Celsius ........................................ 36
Heat and Cool (Auto-Changeover)..................36
Additional Help ................................................36
Google Home and Assistant.................... 36
Perfect Temp and Schedule Mode Functions.. 37
Heat / Cool Mode (Auto-Changeover).............37
Additional Help ................................................37
Control4®Smart Home | Operating
System....................................................... 37
Building36®................................................ 37
Alert Code Priority Types and
Notication Options ......................... 38
FCC Statements................................ 39
FCC Compliance Statement —
PART 15.19 ................................................ 39
FCC Interference Statement —
PART 15.105 (B) ........................................ 39
RF Exposure Information......................... 39
Canada License-Exempt RSS
Standard(s) Operation...................... 39
Index .................................................. 40

4
Features
The Lennox®S40 Smart thermostat recognizes and connects to all Lennox
communicating products to automatically congure and control the heating/
cooling system (based on user-specied settings) for the highest level of
comfort, performance and efciency
Display Features
Specications for the display are as followings:
• 7” Display Capacitive touchscreen display
• Screen resolution: 1280 x 800
• Screen ratio: 16:9
• Dots per inch: 72dpi
External Component Locations
Ambient Sensor
Reboot
(Pin Hole)
Micro USB with
Cap Cover
BOTTOM VIEW
FRONT VIEW BACK VIEW
Humidity
Sensor
BA
CK
V
IE
W
Sub-Base
Figure 1. Thermostat External Components
Reboot Button, Micro USB Connection and Built-in Sensors
The following diagrams in this section illustrates the basic Lennox control
wiring for all compatible components.
NOTE: The screen can also be activated by touching it.
• Ambient sensor - This sensor determines ambient light levels around
the thermostat. If screen brightness is set to AUTO, the thermostat will
automatically adjust screen brightness based on surrounding room light. To
set to AUTO, go to Menu > Settings > Display and enable Auto Brightness.
• Humidity sensor - This is the intake location for the built-in humidity sensor.
Do not block the intake location. The indoor humidity percentage is displayed
(enabled by default) on the home screen. The humidity percentage display
on the home screen can be disabled by going to Menu > Setting > Display.
• Temperature sensor - This determines the room temperature.
• Reboot button - Using a paper clip, press and hold this button for
approximately six (6) seconds to reboot the Thermostat. No settings are lost
using this procedure.
• Micro USB connector with cover - For future use.
Comfort Features
• Smart Away®mode brings Lennox innovation to energy savings by doing
what regular programmable thermostats cannot. Rather than simply following
a set schedule, Smart Away lets the Lennox S40 Smart Thermostat adapt
to your life, perfectly. Smart Away works with the GPS in your family’s
smartphones to detect when the house is empty. When it’s sure that nobody
is home, it sets the temperature back to save energy. Then, when the
Lennox S40 Smart Thermostat detects that someone is on the way home,
it returns the system to normal operation so everyone always comes home
to comfortable air.
• FEELS LIKE®brings Lennox innovation to comfort by optimizing and
automating all the factors that affect how air feels. With the Lennox S40
Smart Thermostat, you simply set a single temperature that you want.
The thermostat will then take into account all the factors that affect comfort,
including heating, cooling and humidity, and create your ideal environment.
It’s very similar to the way the “feels like” temperature on a weather report
works.
• Allergen Defender brings Lennox innovation to cleaner air by monitoring the
air quality and pollen levels in your zip code. When high levels of pollutants
or allergens are reported, the Lennox S40 Smart Thermostat automatically
increases fan speed to create more clean air per hour in your home.
• Climate IQ®- Monitors current climate conditions and automatically removes
excess humidity when necessary (requires Lennox communicating outdoor
unit).
• Schedule IQ - With this feature you only need to program the thermostat
once. Whenever there’s a change in your routine, the thermostat adapts
heating and cooling to match.
• Perfect Temperature (Single Set Point) - In non-zoning applications this
allows a single temperature setting to be used to cool or heat the home.
• Supports air conditioning or heat pump units with up to four stages of heat /
two stages of compressor operation (two stages of heat pump heating, two
stages of auxiliary back-up heating and two stages of emergency heating).

5
• Variable - capacity / multiple - stage Heat • Cool, universal compatibility (gas/
electric/heat pump/air conditioner). When the S40 is used with the variable
speed equipment homeowners can save up to 30% on their energy costs
over single stage equipment and 15% over two stage equipment.
• Dual-fuel capable when using Lennox communicating heat pump unit with
two balance points.
• Humidication measurement and dew point adjustment controls.
• Heat • Cool mode -- Permits control of heating, cooling, humidication, and
dehumidication without user involvement.
• Lennox®Smart Room Sensors for better temperature averaging throughout
your home
Optional Accessories
• Lennox®Wireless Extenders can be used increase the range for your
Lennox®Smart Room Sensors and Lennox®Smart Air Quality Monitor.
• Lennox®Smart Room Sensor. This sensor can be used for temperature
averaging with up to a maximum of six (6) device.
• Lennox®Smart Air Quality Monitor. This device is an air quality monitor that
provides alerts, recommendations, and triggers air purication on demand.
It detects and tracks particulates, carbon dioxide and volatile organic
compounds (TVOCs) inside the home. When poor quality air is detected, it
triggers your system to cycle and clean the air, providing peace of mind that
your family is breathing the most healthy, perfect air.
• PureAir™ and PureAir™S Air Purication Systems - Indoor air quality with
time based notication of consumables including media lters, UVC bulbs,
humidier pads, and PureAir system catalyst service / replacement.
• Lennox®Smart Zoning with supports up to four zones.
• Humiditrol® Enhanced Dehumidication Accessory (EDA).
• ERV/HRV and fresh air dampers are supported when using an Lennox®
Equipment Interface Module.
IMPORTANT
Due to Lennox’ ongoing commitment to quality, features and options are
subject to change without notice and without incurring liability.
Improper installation, adjustment, alteration, service or maintenance can
cause property damage or personal injury. Installation and service must be
performed by a qualied installer or servicing agency.
Downloading Lennox Smart Applications
Scan the QR codes listed as follows to download the specic application that
is compatible with your mobile device.
Lennox Smart Technician App
Google Play
(AndroidTM)App Store
(iOS)
Lennox Smart Thermostat App
Google Play
(AndroidTM)App Store
(iOS)

6
Connecting the Thermostat to the Home Wi-Fi
Multiple S40 Thermostats in the Home
If your home will have multiple S40 thermostats then they all MUST be on the
same 2.4GHz Home Wi-Fi network in order to communicate with each other.
Wi-Fi Considerations
• This thermostat cannot connect to a home wireless router that uses more
than 32 characters in the wireless access point name (visible or hidden).
• This thermostat will support up to a 63 character Wi-Fi password. Passwords
cannot contain blank spaces or % symbol.
• If the home Wi-Fi connection is unsecured, then Wi-Fi security MUST be
enabled. Consult your router documentation on how to enable Wi-Fi security
• This thermostat supports the following Wi-Fi security protocols: WEP, WPA,
WPA2 and WPA3.
• Never use a home guest account.
• Always use a secure connection physically located in the home where the
thermostat is located.
• Lennox S40 and S30 Smart Thermostats are not designed to communicate
with each other even when on the same network.
Supported Wi-Fi Network Types
Supported wireless network types are listed as follows:
Table 1. Supported Wi-Fi Standards
Standard Description
802.11b Compatible.
802.11g Compatible.
802.11n (Wi-Fi 4) Compatible.
802.11ac (Wi-Fi 5) Compatible.
NOTE: MIMO is not supported.
802.11ax (Wi-Fi 6)
Not directly supported. Wi-Fi 6 routers are 100%
backwards compatible with Wi-Fi 5 and older Wi-Fi
devices.
NOTE: MIMO is not supported.
Connecting to a Visible Home Wi-Fi Access Point
1. From the thermostat’s home screen, go to Menu > Settings > Wi-Fi.
2. Slide the option to the ON position to enable Wi-Fi.
3. Select Not Connected to display a list of available access points.
4. Select your home Wi-Fi network.
5. Enter the home Wi-Fi network password and select join to continue.
NOTE: If you wish to see the characters you are typing, check show password.
6. Verify the Thermostat Connectivity Status indicator appears as illustrated
in “Figure 2. Thermostat Connectivity Status”. All connect icons will need to
display green check marks across all connections.
Lennox S40
Smart Thermostat Router Internet Service Provider Server
Figure 2. Thermostat Connectivity Status
Connecting to a Hidden Wi-Fi Access Point
1. From the thermostat’s home screen, go to Menu > Settings > Wi-Fi.
2. Slide the option to the ON position to enable Wi-Fi.
3. Wi-Fi network indicator will show not connected. Select “not connected”.
4. Scroll down and select other.
5. The “enter new network information” screen will appear. Enter the name
of the hidden network.
6. Select your Wi-Fi access point Security. Options are: none, WEP, WPA,
WPA2 and WPA3.
7. Once a security type is selected, a password eld will appear. Enter your
Wi-Fi password to connect to your home Wi-Fi network.
NOTE: If you wish to see the characters you are typing, check show password.
8. Select join.
9. Verify the Thermostat Connectivity Status indicator appears as illustrated
in “Figure 2. Thermostat Connectivity Status”. All connect icons will need to
display green check marks across all connection

7
Electromagnetic Interference Causing Poor Connectivity
Locate the thermostat and router away from other devices that could possibility
interfere with wireless communications. Some examples of other devices that
could interfere are:
• Microwave ovens
• Wireless cameras
• Portable phones and bases
• Baby monitors
• Wireless speakers
• Bluetooth devices
• Garage door openers
• Neighbor’s wireless devices
To eliminate a possible source of interference, temporally disable any devices
and see if Wi-Fi performance has improved.
Wi-Fi Terminology
The following terminology is used in this troubleshooting section:
• Received Signal Strength Indication (RSSI). This indicates the signal
strength of the Wi-Fi router being received by the scanning device (i.e., smart
phone). So the higher the RSSI number (or less negative in some devices),
the stronger the signal.
• Internet Protocol Address (IP address). This is an address assigned by your
home router for each network device (e.g., computer, printer, thermostat).
Received Signal Strength Indicator (RSSI)
The RSSI can be viewed from the thermostat.
1. From the home screen, select Menu > Settings > Wi-Fi > and select right
arrow next to the Wi-Fi network name and then select it again.
2. When selecting the right arrow (>) the second time, a screen will appear
which will display an option to forget the network. In addition IP address,
subnet mask, router IP, DNS, MAC Address, Speed, wireless type, BSSID
and RSSI.
Figure 3. Ideal RSSI
NOTE: If the RSSI signal strength is anywhere between -9 to -69, then the
signal strength is sufcient. If outside this range, then either relocate
the router closer to the thermostat, add a repeater, or move the
thermostat. Adjusting antenna on router or extender/repeater may
resolve the issue.

8
Creating an Account
IMPORTANT
The preferred method to creating a new Lennox thermostat account and
adding the thermostat is by using the Lennox Smart Thermostat App .
You have two methods in creating your account. You can use either the
thermostat or the Lennox Smart Thermostat App.
Using the Thermostat
1. Verify that the thermostat is connected to the home Wi-FI and that
all indicators are green and check marked as illustrated in “Figure 2.
Thermostat Connectivity Status” on page 6. From the home screen, go
to Menu > Settings > Wi-Fi.
2. From your thermostat’s home screen, go to Menu > User Account.
3. Select Create New Account.
4. Enter account details such as your rst and last name, phone, email
address, and password.
5. Select whether you want to receive e-mail updates and reminders.
6. Select allow your dealer to receive notications (highly recommended).
IMPORTANT
Please verify that your dealer has already added their account and contact
information when they installed your thermostat. That information can be
found at Menu > Lennox Dealer Support Access > Local Lennox Dealer
Info. If this information is missing, please contact your local Lennox dealer
and get the information you need to complete your dealer contact information.
7. Select agree to EULA.
8. Enter your information and select Next. Enter your country/region, address,
city, state, and zip code.
9. Select Create Account.
10. It is important that you provide your Lennox Home Comfort System
Dealership remote sharing and Advanced Diagnostics and
Troubleshooting (On / Always) options.
Using the Lennox Smart Thermostat App
NOTE: The following example was using and Android 11 mobile device.
Starting with Android 12 there are new screens addressing precise
location. Always enable precise location when using the Smart Away
feature. All iOS mobile devices as well will require precise location be
enabled for the Smart Away feature to function correctly.
1. Download the Lennox Smart Thermostat App from either the Apple App
Store or on Google Play to your mobile device.
2. Verify that the thermostat is connected to the home Wi-Fi and that
all indicators are green and check marked as illustrated in “Figure 2.
Thermostat Connectivity Status” on page 6.
3. Launch the Lennox Smart Thermostat app.
4. Select Allow. This is required if you intend to upload a photo as a
screensaver on the thermostat.
5. On this screen select the Sign up option to create an account.

9
6. The next pop-up is asking to Allow Thermostat to access this device’s
location. This is required if you intend to use the Smart Away feature to
control your thermostat. Select While using the app.
7. If you plan to use the Smart Away feature, this select Settings > Location
permissions. Select Allow all the time. Select the left arrow next to
Location Permission to return to the previous screen.
8. Complete all elds on the Sign Up screen. Also enable Email Updates
and select the box that you agree to the Lennox EULA.
9. Select the Sign Up button at the bottom of the screen. A pop-up screen
will indicate that your account was successfully created. Select OK to
continue.

10
10. Now you will need to add your thermostat to your user account. First go
your thermostat and from the home screen go to menu > user account and
then near the bottom of the screen, select Generate pin. A ve digit pin
number will appear.
11. Return to your mobile device and select the Plus sign on the screen. Then
enter the 5 digit number displayed on the thermostat here. Then select
Add.
12. The next screen will provide the option to Add New Home. Select that
option.
13. Enter the home information required on this screen.
14. It is highly recommend by Lennox to check the option to allow dealers
to receive service alerts and if possible remotely x any issue that may
occur with your thermostat. See “Home Screen Details” on page 11
for understanding why it is important to allow your Local Lennox Dealer
access.
15. Select Done.
16. A screen will appear asking that you verify your home address. If everything
is correct, select Done.

11
Home Screen Details
Menu
Time and
Date
Manual setting
to put system in
pre-define set points
Manual adjustment
for Heating
Manual adjustment
for Cooling Accuweather
(based on user’s
account zip code)
Indoor
Humidity
Actual Room
Temperature
Marker
Heating Adjustment
Tool
Cooling Adjustment
Tool
System Name or
Zone Name
Current Room
Temperature
Animated icons will appear here
for active call for cooling, heating,
ventilation and various fan functions
This location could display Feels Like,
Inside or Average when
temperature averaging only is
active. What is displayed depends on
the system setup.
Selecting this
will return you to
the thermostat
or last viewed
zone homescreen
Selecting Status will display humdity level, various fan operations, schedules
being used, ventilation and other various system operations.
Selecting this will show detail information and operational status of the
thermostat, all zones (if applicable), Lennox Smart Room Sensor, Lennox
Wireless Extender, Lennox Smart Air Quality Monitor and PureAir Sdevices.
Indicates termperature
averaging is active Cleaning Air Various system operation status icons
will appear here and simultaneously under
the Status selection at the top center of
the screen.
Figure 4. Thermostat Home Screen

12
Temperature Settings
Large display of current
inside temperature (°F or °C) Selecting the heat or cool set point
indicators on the round temperature band,
or selecting the Heat-To or Cool-To buttons
displays the heat or cool menu screens
Both heating and cooling set point
indicators on the round temperature band
and the Heat-To and Cool-To buttons are
displayed if the system is set to Heat/Cool
mode or if an active schedule is set to Heat/
Cool mode.
Heating and Cooling Set
point Indicators on the round
temperature band
Current cooling set point
temperature Button (Cool-To)
Current heating set point
temperature Button (Heat-To)
Current Outdoor Temperature and Weather Forecast
Displays current outdoor
temperature in °F or °C
and the current weather
forecast
The default outdoor temperature is supplied
by the outdoor air temperature sensor or
the Wi-Fi data connection (homeowner
selectable on the thermostat). The outdoor
sensor is furnished as standard with Lennox®
Communicating outdoor units, optional for
conventional units.
Time and Date Display
Displays current date and time
NOTE: Date and time are automatically set based on the address zip code if the
thermostat is connected to the Internet and user account completed.
Manual adjustment can be made if the thermostat is not connected.
Humidity Display
Displays the current inside relative humidity below current indoor temperature.
Away
The user can manually put the system into away mode by pressing the Away
icon located on the bottom left-hand side of the home screen. When the system
is in Away a status notication (Away is Active) is displayed on the right-hand
side of the home screen.
In order to exit Away, select Cancel located on the bottom left-hand side of the
home screen. Selecting the Away is Active status notication will display the
current set point range for high and low temperature settings. There is also the
option to select Cancel here as well by selecting Yes.
While in Away, the Away Set points are used to control the high and low
temperature setting for the thermostat and all zones simultaneously if Smart
Zoning is installed. The Away Set points can be changed from the default
values by going to Menu > Settings > Away.
Temp
Returns to the thermostat home screen or the home screen for a specic zone
if Smart Zoning is installed. Displays current temperature screen for the current
system where the thermostat and sensors are located.
Select the Temp button from the Status or My Home screen to return to the
thermostat home screen or last zone viewed.
Status
Displays current system operating status for the current system/area where
the thermostat and sensors are located. Details such as humidity levels, Feels
Like being active, any of the various fan modes and various other system
background activities.
My Home
Lennox Smart Home devices and equipment such as multiple S40 Thermostats
on the same home network, Smart Room Sensors, Wireless Extenders, Air
Quality Monitor, PureAir Sand Zoning Control are all optionally purchased
items and will appear on this screen if installed.
Figure 5. My Home Screen

13
This screen will display multiple thermostats in the home. It will also display
others devices such as Lennox Smart Zoning (up to four zones per thermostat),
Lennox Smart Sensor, Lennox Smart Air Quality Monitor and PureAir S.
• Selecting any item on this screen will display the detail screen for that device.
• A yellow or red dot with an explanation point indicates there is an alert
condition for that specic device.
Thermostats and Zones
Selecting the icon will bring up either the thermostat home screen or in a zoning
system the home screen for the specic zone selected if zoning is installed.
For further details concerning zoning control, see “Smart Zoning System” on
page 28.
Lennox Smart Room Sensor
IMPORTANT
The Lennox Smart Room Sensor is currently not compatible with systems
using the Lennox Smart Zoning System (iHarmony) installed.
NOTE: The Lennox Smart Room Sensor is an optional accessory sold
separately.
Selecting this options will display the details for the sensor selected. What is
displayed is the current temperature for the room that the sensor is located in.
Additional details include:
• If sensor is participating in temperature averaging.
• Humidity level in the room
• If the room is occupied or unoccupied.
• Battery percentage
• Wi-Fi connection strength.
See “Lennox Smart Devices” on page 32 for further details.
Lennox Smart Air Quality Monitor
NOTE: The Lennox Smart Air Quality Monitor is an optional product sold
separately.
Selecting this option will display the Current Air Quality. Color indicators are
Green indicates good, Yellow indicates fair and Red indicates poor.
In addition a bluetooth signal strength indicator is provided to show the signal
status.
There are also three options that can be selected. Those options are Monitor
Settings, Air Pollutants and More Information.
When selecting Monitor Settings the following options are available:
• Air Quality Monitor Name allows the user to rename the sensor using the
virtual key board.
• Device Type will always show Monitor.
• About Air Quality Monitor will list model and serial numbers along with
rmware version.
• Level of Indoor Air Cleanliness. Options are High, Medium and Basic
(Most Economical)
Information concerning Air Pollutants and More Information can be found
further in this guide (see “Lennox Smart Air Quality Monitor” on page 33).
Lennox Wireless Extender (BLE)
NOTE: The Lennox Wireless Extender is an optional product sold separately.
Selecting this icon will bring up the wireless strength indicator. There is an
additional selection called Extender Settings. This screen includes:
• Extender Name: This will show the current name of the extender and can
also be renamed from this screen.
• Device Type: Extender
• About Extender: This will list the model, serial number and rmware version.
For further details, see “Lennox Wireless Extender” on page 33.
PureAir S
NOTE: The Lennox PureAir S is an optional product sold separately.
Selecting this option will display the PureAir S lter life. Red indicates 1-10%
lter life left, yellow indicates 11-30% lter life left and green indicates 31-100
lter life left. Also available are:
• More Info: Information is listed here on the PureAir Sproduct.
• Reminders: You can set service reminders here for 1 day, 1 week, 1 month,
3 months or custom.
• Service Contracts: This will list your service contact if it has been entered
into the thermostat.

14
Home and Status Screens Icon Descriptions
Table 2. Home and Status Screens Icon Descriptions
Icon Function or
Screen Text Purpose
Menu Selecting this icon will bring up user and installer menus.
1Menu with
Notication
Icon
If there are one or more notications this icon will appear over the menu icon. The number in the center indicates how many
active notication are present.
Feels Like is Active or Turning Feels Like on
Smart Away is
Active or Away
is Active
When the away icon is Selected, the system will automatically use energy saving settings - heat-to 62 (16.5) and cool-to
85 (29.5). Temperatures can be adjusted by pressing on the available temperature setting (i.e., heat-to or cool-to). To exit
away, press the cancel icon. In a zoning system, all zones are set to a single heat-to and cool-too setting. Note that when
manually selecting Away from the home screen, the Smart Away feature (if enabled under settings) will be temporally
disabled until Away is canceled.
Heating System is heating the home. This animated icon will appear above the system name on the home screen.
Cooling System is cooling the home. This animated icon will appear above the system name on the home screen.
Humidifying If humidication equipment is installed and congured, the system will display this message when adding humidity to the
air in the home.
Dehumidifying
The system can be used in cooling mode to help remove excessive humidity as determined by the user setting. Go to Menu
> Settings > Humidity > and turn on dehumidify. Then adjust the acceptable low and high humidity levels in the home
with the dehumidication set-point slider.

15
Table 2. Home and Status Screens Icon Descriptions
Icon Function or
Screen Text Purpose
Defrosting The heat pump system is defrosting the outdoor unit coil (only when required).
Emergency
Heat
All heat pumps operating in northern climates below 35°F (1.6°C) normally need a supplemental heating source. Usually it
is in the form of electric heating provided by the indoor unit. Other sources could be gas, oil, or hot-water back-up systems
as well. The supplemental heat is also referred to as “second-stage” or “back-up” heating, with “rst-stage” being the heat
pump only. Emergency heat is when you use your supplemental heat (2nd stage) by itself, without the use of your heat
pump (1st stage heat). Not available for non-heat pump systems.
Auxiliary Heat
Is only available with heat pump system. If outdoor temperature is above the high balance point, only the heat pump will
operate - default 50°F (10°C) high. If outdoor temperature is below the low balance point, only auxiliary heating will operate
- default 25°F (-4.0°C) low. If outdoor temperature is in-between the high and low balance point, both the heat pump and
auxiliary heat sources can operate.
Will start soon A ve minute safety delay prevents the compressor from operating too soon after shut-down to allow internal pressures to
equalize.
Ambient
lockout
This indicates that either the outdoor temperature is above or below the balance point temperature settings. The low
balance point setting prevents heat pump heating below the set point and back up heat will be used. Typically the default is
25°F (-4.0°C), but that setting can be adjusted by your dealer. At 25°F (-4.0°C) or below for example, only auxiliary heating
(electric or gas) is used. If the high balance point is set to 50°F (10°C) for example, which is also adjustable by your dealer,
then auxiliary heat will not be allowed. Only heat pump heating will be used. Anytime the outdoor temperature is below or
above the balance point temperature settings, the ambient lockout notice will appear on the home screen.
Fan is running Fan set to ON. Fan is NOT following the schedule and runs continuously until it is changed from the selected mode.
Fan in auto
mode is active. Fan set to Auto. Fan will follow the fan setting in the selected schedule.
Fan in circulate
mode is active.
Fan set to Circulate. Fan is following schedule and cycles during periods of equipment inactivity. Circulate run time is
dependent on user settings.

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Table 2. Home and Status Screens Icon Descriptions
Icon Function or
Screen Text Purpose
Fan in Allergen
Defender mode
is active
Allergen Defender: Go to Menu > Settings > Fan to turn on or off Allergen Defender. Internet weather must be enabled
and the pollen count is high for the following pollens (Grass, Ragweed, Mold, Tree and Overall Pollen) the fan will run
between heating or cooling demands to help clean the air. Works best with MERV 11 or higher lter.
Allergen Defender only runs when no other fan modes (On, Auto or Circulate) are being utilized.
System Under
Test
Typically occurs when the system has had a power interruption. The thermostat starts to look for the indoor and outdoor
controls. Sometimes the outdoor control takes longer to boot up and therefore does not respond to inquiry by the thermostat.
Recycle power to system may resolve issue.
Aux Heat Auxiliary heating is active.
Load shedding,
wait time 45 min
Action to reduce the load on something, especially the interruption of an electricity supply to avoid excessive load on the
generating plant.
Service Urgent
Service Urgent means that a service call is needed to get the system running.
Selecting the icon will display a pop-up screen. Service Urgent. The system has encountered a problem. Alarm ID: xxxx
and a description of the alarm is provided. Select OK to cancel the pop-up screen.
Coasting to
Perfect Temp Coasting allows the current temperature to reach the desired single set-point without the system doing any work. The red
arrow indicates the temperature is less than the desired set point. The blue arrow indicates is greater than the desired set
point.
Coasting to
Perfect Temp
Ventilating or
Ventilating unit
(specic Time)
This indicates the system is actively ventilating and the precise time the cycle will end. Selecting cancel will terminate the
current ventilation session.
Selecting the icon will display a pop-up screen. Ventilating until x:xx pm. Do you wish to cancel. Options are No or Yes.

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Table 2. Home and Status Screens Icon Descriptions
Icon Function or
Screen Text Purpose
Peak Monitoring
until x:xx pm -
x:xx pm
The utility company will automatically set the energy savings time period. You can select cancel to exit this mode.
By canceling you will be opting the system out of the current active energy savings events. A pop-up screen will ask you to
verify this is what you wish to do.
Selecting the icon will display a pop-up screen. Peak Monitoring will be active from x:xx pm to x:xx pm.
Transitioning to
next schedule The system is following an active schedule and is transitioning to the next temperature setting based on a time indicator.
Schedule
hold until next
period
Selecting the icon will display a pop-up screen. Schedule will hold until next schedule setting. There is also the option
to select duration of hold or cancel. Options to select are Cancel, Duration and Hold.
Schedule Hold
until xxxx
Two pop-up may appear.
Schedule will hold. Do you wish to cancel? Options are Yes or No.
Schedule will hold until xxxx. Do you wish to cancel? Options are Yes or No.
Cleaning Air When the Lennox Smart Air Quality Monitor has determined that there is poor air quality in the home it will run the indoor
unit fan or any other indoor air quality devices installed to clean the air. Selecting this notication on the thermostat home
screen will allow you to view details concerning the air quality or postpone the air cleaning for a specied time period.
From the thermostat home screen select Cleaning Air and then you have the option to view details and postpone. Selecting
postpone will display a screen where you can select 1, 2, 4, 8 and 24 hours.
Postponing
Cleaning Air

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Menu
Select the Menu button on the home screen to display the Menu screen.
If multiple thermostat control systems are available they will be shown below
the General menu settings.
General
Notications
Filters for displaying notications are All Notications (options that can be
checked off are All Notication, Service Urgent and Maintenance) The
second lter option is All Time Periods and the selection options are All Time
Periods, Last 24 hours, Last 30 days and Last 12 months.
User Account
This section is only accessible if the thermostat has an active connection to
Wi-Fi. On this screen you have the option to sign into an existing account or
create a new account.
Also available is the Generate Pin option if you are setting up your account
using the Lennox Smart Thermostat App.
Once the account has been created and thermostat added to that account,
then information under this section can be edited at any time.
Selecting User Account will take you to the User Settings screen. There you
can select your Email (>) to view and edit information such as correct First and
Last Name, Change Phone Number, Email and Password, View EULA and
toggle on Email Updates and Monthly Report Email (System Performance
Information).
There is also a option to Move Out at the bottom of the User Settings screen.
Selecting this option will remove the thermostat from your Lennox account.
This would be done typically if your were selling your home or replacing the
thermostat.
Display Settings
The available settings are:
• Auto Brightness with an option for either ON or OFF. When set to OFF,
there is an adjustment bar to set the brightness level.
• Screen Lock with an option Unlocked, Partially Locked and Locked.
Press and hold the lock icon for 3 seconds
to unlock (Partially Locked and Locked)
Figure 6. Unlocking
NOTE: Lock screen can also be used to clean the thermostat screen.
• Proximity Sensor which is ON by default. When set to ON, the display will
automatically turn on when you approach it. When set to OFF, you will have
to touch the screen for it to turn on.
• Screen Saver which by default is set to OFF. Options are OFF, Weather,
Power Save (blank screen) and photo. Photo can be upload to the thermostat
by using the Lennox S40 Smart Thermostat app.
» Use the Lennox Thermostat App, select Menu > Display Settings
> Screensaver and upload an image from this screen. If the upload is
successful a conrmation screen will indicate so.
» From the thermostat home screen, select Menu > Display Settings >
and turn on Screensaver and then select Photo. The photo you just
uploaded from the Lennox Smart Thermostat App should appear
and ask you to accept or reject. Select accept to use the picture as a
screensaver.
• Home screen settings are:
» Outdoor Temperature by Source. Options are Accuweather or
outdoor temperature sensor. Default setting is Accuweather. To display
Accuweather you have to have an good Wi-Fi connection, connected to
the Lennox server and logged into your user account.
» Outdoor Weather. This options allows the user to turn on or off outdoor
weather on the home screen.

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» Indoor Humidity. This options allows the user to turn on or off indoor
humidity being displayed on the home screen.
Lennox Dealer Support Access
IMPORTANT
You have made an investment in your heating and cooling system and you
expect peak performance. With a simple, ON / Always option, this new smart
thermostat forever changes HVAC equipment diagnostics, maintenance, and
repair. It provides basic maintenance notications and alerts, performance
reports, and the ability for dealers to remotely diagnose and troubleshoot.
This proactive and responsive HVAC care is valid for the lifetime of the HVAC
system. Promising peace of mind by doing away with unnecessary dealer
visits, avoiding potential repair costs, and ensuring nothing short of perfect
air. In some instances, the dealer may be able to correct a problem without
ever having to come to your home, saving you time and money.
Local Lennox Dealer Info: Here you have the options to either just display
information already populated on this screen or add or correct the service
contact information. This is where you can add details such as Name, Country,
Address, phone, email and website information.
Dealer Support Access:
• Remote Sharing - Allow service provider to remotely view the status of your
system. By default this option is set to OFF.
• Advanced Diagnostics and Troubleshooting
» Off - You will not be give authorization to service provider to troubleshoot
your system remotely.
» On / Always -You will always give authorization to service provider to
troubleshoot your system remotely.
Alerts and Notications:
Allows service provider to be notied when your systems needs maintenance.
By default this is set to OFF.
System
Mode
This screen will allow the user to set the operating mode of the system. Options
are Emerg Heat, Heat Only, Heat / Cool, Cool Only and Off
Schedule (Single Zone)
All schedule proles shown in Figure 7 can be can be customized including
schedule name, starting time for each period and related heating and cooling
temperature settings for each period.
Figure 7. Schedule Options Screen
Schedule Proles
• No Schedule - System is not following a schedule. All changes are performed
manually.
• Schedule IQ - This schedule operating in heat / cool mode and answering a
few simple questions will allow the system to know how to set the temperature
for the home based on time settings. By default there are two times and
temperature settings which can be adjusted using the edit schedules option.

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Figure 8. Schedule IQ Setup Screen
» At home day wake-up default time is 7:00am and low temperature
setting of 67°F and high temperature setting of 80°F. Start time can be
adjusted by press on the current time setting and can be adjusted as
exampled in gure 6
» At home night sleep default time is 11:00PM and low temperature
setting of 66°F and high temperature setting of 84°F.
» Away - When away from home, Smart Away when enabled (see
“Away” on page 12) is used to set the temperature while the home
is unoccupied. Default low temperature setting of 62°F and high
temperature setting of 85°F. Temperatures for any of the options above
can be adjusted by sliding the low and high temperature circle left or
right on the sliding scale.
Figure 9. Schedule IQ Setup Screen
• Summer – Provides the average Summer indoor cooling set points for home
temperatures. Temperatures and time periods can be adjusted to provide
your desired set points.
• Spring/Fall - Provides the average Spring/Fall indoor cooling set points
for home temperatures. Temperatures and time periods can be adjusted to
provide your desired set points.
• Winter – Provides the average Winter indoor heating set points for home
temperatures. Temperatures and time periods can be adjusted to provide
your desired set points.
• Save Energy – Provides the recommended Energy Star set points
recommended by the Environmental Protection Agency energy savings.
NOTE: All of the above schedule proles can be customized to meet your
particular needs. .
Schedule Options
On each schedule screen except for Schedule IQ, there is an option located
in the top right-hand corner of the screen that will allow you to customized your
experience even further.
Figure 10. Schedule Screen Options