Lennox
®
S40 Smart Thermostat Installer Quick Start Guide
508295-01 October 2022
Step 1
Step 2
A. Use sub-base as a template to mark the desired mounting hole locations on the wall. Drill holes and use provided
wall anchors if needed.
B. Pull about three inches (75mm) of thermostat wire
through the opening and remove the outer thermostat
wire jacket.
Step 3
Running Wires and Installing Sub-base
Wiring Connections
NOTE: For basic communicating wiring Options 2 and 3 and different equipment configurations,
please reference the Lennox S40 Smart Thermostat Installation and Setup Guide.
IMPORTANT: Seal wire hole in wall to prevent
cold or hot air from affecting the internal
temperature sensor of the thermostat.
A. Hold the thermostat by the edges, line it up with the
sub-base (horizontal position) and move the
thermostat toward the sub-base.
B. Center the cavity on the back of the display over the
sub-base.
C. Gently press on the edges of the thermostat until
you hear the mounting snaps engage. Be careful
not to apply force directly on the glass.
D. Once the thermostat is connected, it may take up
to 45 seconds for it to power up.
NOTE: If the thermostat is removed from the sub-base,
the thermostat will shut down and will not be
able to communicate with the system.
NOTE: Do not remove the label covering the
thermostat screen until after power is applied
to the system.
Attaching Thermostat to
Sub-base
Drill hole and run
wiring
Improper installation, adjustment, alteration,
service or maintenance can cause property
damage, personal injury or loss of life.
Installation and service must be performed by
a licensed professional HVAC installer
(or equivalent) or a service agency.
WARNING
Scan QR Code for S40 Installation
and Setup Guide
Français / Español
lennoxsmartertogether.com/dealer-access
lennoxsmartertogether.com/spanish-french
Step 4
Commissioning using the
Lennox
®
S40 Smart Thermostat
Step 5
Helping Homeowner Connect to Wi-Fi
Dealer
Info
General
Information
Equipment
Found
Reminders
Shows welcome screen. Error
will show if the thermostat is not
connected properly. Select
Language.
Set time, date, language and
temperature (Fahrenheit or Celsius).
Automatically detects communicating
equipment and equipment interface module
(EIM) if present. Non-Communicating
equipment is added in this screen. Smart
Zoning may appear after this screen if
installed along with airflow per zone screen.
Specify reminder types and reminder
frequency (ex: change filter every 3
months).
Welcome
Select
method
to setup
Commisssioning using the Lennox
®
Smart
Technician App
1. Thermostat will show welcome screen. Error will show if the
thermostat is not connected properly. Select your desired
language.
2. Select Continue setup process through the Technician
App to use the Lennox
®
Smart Technician App.
3. The next screen is the QR codes for both IOS and Android
If you have not already downloaded the app, here is an
opportunity to do so now.
4. Start the Technican app on your mobile device. The first
screen to appear is the Welcome screen. Here you willl
select the desired language for the Lennox
®
Smart
Technician App.
5. Select Configure new system.
6. Connect with Thermostat. Make sure your mobile device’s
bluetooth is enabled.
7. Return to the thermostat and select Start. The thermostat
will now display an ID number.
8. Return to the Lennox
®
Smart Technician App and look for
the thermostat’s ID on the app screen. It will be the same
as displayed on the thermostat’s screen.
9. Select the thermostat’s ID listed on the app.
10. A screen will indicate it is connecting to the thermostat. If
connection is successful the next screen will indicate so.
11.
IMPORTANT: Enter dealer ID number. If not available,
enter phone number associated with the dealer account.
This will enable ability to do advanced diagnostics and
remote sharing if permitted by homeowner.
12. Set time, date, language and temperature unit (Fahrenheit or
Celsius).
13. Automatically detects communicating equipment
and EIM. Non-Communicating equipment is
added in the next screen. Smart Zoning may appear after
this screen if installed along with airflow per zone screen.
14. Specify reminder types and reminder frequency
(ex: change filter every 3 months).
15. Continue with the on-screen prompts to complete
the setup of the system.
To intially add Lennox
®
Smart Sensors, Lennox
®
Smart Air
Quality Monitor and Lennox
®
Wireless Extenders, the
Lennox
®
Smart Technician App must be used. Go to
Menu > Settings > Advanced Settings > View Support
Service Control Center > Equipment Settings > Add Sensors.
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. Press on Not Connected to display a list of available access points.
4. Locate home network and select the network name.
5. Enter the home Wi-Fi network password and press join to continue. If successful the
Thermostat Connectivity Status indicator as illustrated below will show checkmarks
across all connections.
NOTE: If you wish to see the characters you are typing, check show password. The thermostat will
support up to a 63 character password. Passwords cannot contain blank spaces or % symbol.
NOTE: Whether connecting to a visible or hidden network, if successful, a check mark
will appear above both the router and Internet icons. For information on connecting
to hidden networks, please reference the S40 Homeowner Guide.
Select continue setup process
through the thermostat.
IMPORTANT
ADVANCED DIAGNOSTICS & REMOTE SHARING
Protect homeowner investment and peace of mind with active monitoring of system
operations through the Lennox
®
S40 Smart Thermostat. This feature is free of charge and
provides basic maintenance reminders, alerts homeowner of potential issues, and can
even allow the homeowner to remotely share diagnostics with the Lennox dealer to
troubleshoot and fix problems. This proactive care helps eliminate downtime
and avoid unnecessary service visits and repair costs, ensuring nothing short of perfect air.
Please share this information with homeowner as you ask them to accept the Advanced
Diagnostics & Remote sharing permissions.
NOTE: Installer, please share the homeowner quick start guide with homeowner.
Enter dealer ID number. If not
available, enter phone number
associated with the dealer
account. This will enable ability
to do advanced diagnostics and
remote sharing, if permitted by
homeowner.
IMPORTANT
Use the sub-base as
a template to
mark the desired
mounting hole
locations on the wall.
Thermostat Sub-base
(Front View)
Install sub-base with arrow
pointing up.
Thermostat
(Rear View)
Mounting Snaps
Lennox Communicating
Outdoor Unit
Lennox Communicating
Thermostat
18 or 22AWG
Standard Thermostat
Cable (4-Conductor)
Indoor Unit Communicating Control
(Using Non-Shielded Wiring)
OPTION 1
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