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At present, we are conducting a thorough investigation into numerous smart thermostat producers, with our main focus on Lennox.

Lennox has been in the HVAC industry for over a century producing a wide range of systems for both commercial and residential.

Their latest HVAC controls have all of the smarts that you'd expect from the industry leaders Nest and Ecobee.

In this article, I provide helpful links to owners' manuals for those who have run into difficulties with their thermostats.

I also touch on some controls you'll need to know to operate your system along with some troubleshooting tips for common problems.

Lennox Thermostat Manuals

It can sometimes be difficult to find the correct instruction manual for your device, particularly for older, discontinued models.

Use the search bar below to find your specific Lennox Thermostat Manual. You can enter the model number, name or description. We’ve also included images to help.

If you have a manual you would like to list, submit it here. Or, if your model is not listed, leave a comment below.

All imagery and manuals are copyright © Lennox. Please visit for the most up to date manuals and product information. You can read our DMCA policy here.

Model Image Model ID Description Document Updated Downloads
Supersedes 507342-01
507342-01, 5/2017
iComfort Wi-Fi Thermostat 2017 Owners Manual
Document(s) Updated: 2017
Elite Series
Programmable Touch Screen Thermostats 2005 Owners Manual
Document(s) Updated: 2005
3000 Series Thermostats
ComfortSense 3000
Programmable & Non-Programmable Thermostats 2008 Owners Manual
Document(s) Updated: 2008
51M37 Merit Series
51M37, 05/05, 505,050M
5/2 Day Programmable Thermostat 2005 Instruction Manual
Document(s) Updated: 2005
iComfort E30
Smart Thermostat 2017 Installation Manual
Document(s) Updated: 2017
icomfort Wi-Fi Thermostat
Touch Screen Programmable Communicating Thermostat 2012 Installation Manual
Document(s) Updated: 2012
icomfort Thermostat
Touch Screen Programmable Communicating Thermostat 2009 Installation Manual
Document(s) Updated: 2009
81M26, 81M27, 81M28
PROGRAMMABLE THERMOSTATS with Humidity Control 2005 User Manual
Document(s) Updated: 2005
iComfort Wi-Fi Thermostat
507341-02 5/2017
Touchscreen Programmable Communicating Thermostat 2017 Installation Manual
Document(s) Updated: 2017
icomfort Wi−Fi Thermostat
Touch Screen Programmable Communicating Thermostat 2012 Owners Manual
Document(s) Updated: 2012
ComfortSense 3000 Series
Non‐Programmable Thermostat 2018 Instruction Manual
Document(s) Updated: 2018
ComfortSense 3000 Series
7−Day Programmable Thermostat 2008 Instruction Manual
Document(s) Updated: 2008
Controls (51m32)
51M32, 504,865M, 09/04
Merit Series Thermostat 2003 Instruction Manual
Document(s) Updated: 2003
iComfort S30
Smart Hub 2.0, 507537-04 4/2018
Ultra Smart Thermostat 2018 User Manual
Document(s) Updated: 2018
Comfort Sense
Touchscreen Thermostat 2008 User Manual
Document(s) Updated: 2008
ComfortSense 7000 Series
TTTouch Screen Programmable Thermostat 2009 Owners Manual
Document(s) Updated: 2009
ComfortSense 5500
Color Touchscreen Programmable Thermostat 2015 User Manual
Document(s) Updated: 2015
43558, 41653
Programmable Heat Pump or Multi-Stage Auto Season Thermostat 2004 Owners Manual
Document(s) Updated: 2004
ComfortSense 5000 Series
Touchscreen Thermostat 2008 Owners Manual
Document(s) Updated: 2008
iComfort S30 Smart Thermostat
12U67, 507536-02
Color Touchscreen Programmable Wi-Fi Communicating Thermostat 2017 Installation Manual
Document(s) Updated: 2017
ComfortSense 3000 Series
5/2 Day Programmable Thermostat 2008 Instruction Manual
Document(s) Updated: 2008
ComfortSense 3000 Series
Non-Programmable Thermostat 2008 Instruction Manual
Document(s) Updated: 2008
ComfortSense 7500
13H14, 507503-01, 10/2015, Supersedes 7/2015
Color Touchscreen Programmable Residential Thermostat 2015 User Manual
Document(s) Updated: 2015
ComfortSense 7500
13H14, 507504-02
Color Touchscreen Programmable Thermostat 2017 Installation Manual
Document(s) Updated: 2017
iComfort E30
507687-03 4/201
Smart Thermostat 2018 User Manual
Document(s) Updated: 2018
ELO183B 101/114
Elo183b Series Units 2015 Installation Manual
Document(s) Updated: 2015

How to find your Lennox Thermostat’s model number?

Look for a label on the device, usually on the back (where you'll need to detach the faceplate) or inside the cover. If the device is already set up and has an LCD display, you’ll also find the information through the menu.

Lennox Thermostat Instructions

Here are some general steps for common operations you can do. Again it's always best to check the specific Lennox thermostat manual for exact instructions.

thermostat 13


Older models have physical buttons MENU (then go to PROGRAM) or PROG to allow you to set schedules. Those with a SCHED button, go through SCHED > EDIT. 

For newer touchscreen models like iComfort, access your Features screen (likely through the right arrow from Home) then “edit programs”. Press HELP for simple instructions.

Program/Temperature Hold

For most earlier models, you can press the Up/Down buttons to temporarily override the schedule. Pressing the HOLD button instead will initiate permanent HOLD.

Models with HOLD TEMP can select from either of the two modes, as well as a vacation hold for longer durations.

For newer touchscreen models, press a set temp button (cool to or heat to). This will override the programming.


Fan setting

Press the FAN button (or “fan is AUTO/ON/CIRCULATE”) if your model has it.

For owners of models with the modes/schedules option such as the iComfort E30, pres it then select the fan icon.


Some older models have the reset button (unlabeled, recessed) within the door or behind the product which you can press or long-press to reset it to factory defaults. For newer ones, you’ll find the function within the settings in the interface.

Steps vary per model, sometimes even models of the same series. Make sure to download the correct Lennox thermostat manual for your model.

Lennox Thermostat Troubleshooting

Below are some common issues you might encounter with your thermostat and what may be causing the problem.

Wi Fi Router

Wi-Fi connection problem

This is a common issue with Wi-Fi and smart thermostats. First, check changes to your network. Try to reconnect the thermostat to your network.

In case of interference, identify other radio-emitting devices or appliances close by between your router and thermostat. Common culprits are microwave ovens, Bluetooth devices, or other wireless devices.

You could also check the signal strength (RSSI) of your Wi-Fi, which you can do within the network settings of your Wi-Fi/smart thermostat.

Heating/cooling, display malfunctioning

With cooling or heating problems, check your schedule. Also, check if the proper indicator is displayed (Heat On or Cool On).

Check your power sources. If your thermostat uses a battery, it might be drained already. Otherwise, check the C-wire connected to your thermostat, other power wiring on your system, or your breaker (tripped, blown fuse, etc.). A lot of issues are caused by this, so you might consider a technician.

Types of Lennox Thermostats

Lennox has a convenient range of thermostat models that cover most budgets and needs for home air comfort. The current lineup is capable of programming/scheduling and works with most types of HVAC systems.

Smart Thermostats: iComfort S30, E30, M30

This lineup is led by the flagship, iComfort S30 Ultra Smart Thermostat, which Lennox describes as “the ultimate controller” for home comfort. It has the smart features you need and more but is reserved for Lennox equipment only.

You’ll be happy with either the E30 or M30 smart thermostats. The M30 has the smart features of other competitors, and E30 has the nice-to-haves you might want, such as weather screensavers, “allergen defender”, or humidity control.

iComfort Wi-Fi Touchscreen (limited to Lennox equipment) and ComfortSense 7500/5500 models

These models give you wireless connectivity, providing savings, and still have the features you need, and more that you might want.

The ComfortSense models might not have those smart functionalities, they still provide touchscreen convenience and clever features, such as temperature monitoring, energy reports, and filter reminders.

ComfortSense 3000 Series

Last on the current lineup, but might just be the perfect choice for your setup. It gives you that “just works” simplicity at a value price, with the basics and more.

To help educate you further about current Lennox thermostats, check out this product comparison document by the company.


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1 Comment

    Posted July 16, 2022 at 5:54 am

    All of LENNOX THERMOSTATS are not compatible and I can’t , for any reason why? The diagram s to connect to the system that has the ” RI+ I- C” Wall connector Red(R) Green (G) White (W) and Common (C) is not shown on any of the thermostat. Why? All other Thermostat , even the ones that require the “C” wire gives you a connection diagram, from the $13.95 -the $459.99 ones. Your M-30 will never come loose from the wall. shows great instructions to connect the stud. nothing about how to connect the wires from the wall to the thermostat.

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