Mastering the Art of Overriding Lennox Thermostats: A Comprehensive Guide

Overriding a Lennox thermostat can be a complex task, but with the right knowledge and approach, it can be a straightforward process. This comprehensive guide will walk you through the various methods to override your Lennox thermostat, catering to different system configurations and user preferences.

Understanding Your Lennox System

Before attempting to override your Lennox thermostat, it’s crucial to identify the specific model and system you have. This information will guide you through the appropriate steps and ensure a successful override.

Lennox EL296E Furnace

If you have a Lennox EL296E furnace, you can convert it from a communicating to a standard thermostat by following these steps:

  1. Locate the DIP switches on the control board of your Lennox EL296E furnace.
  2. Refer to the installation manual or manufacturer’s instructions to identify the correct DIP switch settings for a standard thermostat configuration.
  3. Carefully adjust the DIP switches to the appropriate positions.
  4. Install a new thermostat, such as an Ecobee3 lite, to complete the conversion.

This change will turn your highly efficient variable speed system into a 2-stage system, which may result in some efficiency loss but can save you money in the long run by avoiding frequent thermostat replacement.

Lennox iComfort S30 Thermostat

If you want to override the temperature settings temporarily on your Lennox iComfort S30 thermostat, follow these steps:

  1. Locate the Lennox icon on the bottom right of the thermostat display.
  2. Press and hold the Lennox icon for a few seconds.
  3. Press the “Reset” button on the thermostat.
  4. Wait for a few seconds, and the thermostat will reset to its default settings.

This method allows you to quickly override the temperature settings without making permanent changes to your system.

Replacing Lennox iComfort Thermostat with Nest

how to override Lennox  thermostatImage source: Lennox Ac by Raysonho

If you want to replace your Lennox iComfort thermostat with a Nest thermostat, you’ll need to bypass the Interface board and directly connect the necessary wires. Here’s how to do it:

  1. Identify the 3 R’s (from the AC, the furnace, and the thermostat), the 3 C’s, and the 3 Y1’s.
  2. Connect the 3 R’s, the 3 C’s, and the 3 Y1’s without the Interface board.
  3. Connect the W from the furnace to the W from the Nest thermostat.

Please note that this method requires some electrical knowledge, and it’s recommended to consult the furnace’s installation manual or hire a professional if you’re unsure about the process.

Advanced Troubleshooting and Considerations

In some cases, overriding a Lennox thermostat may require more advanced troubleshooting or considerations. Here are a few additional factors to keep in mind:

Compatibility and System Integration

Ensure that the new thermostat you’re installing is compatible with your Lennox system. Check the manufacturer’s specifications and consult with a professional if you’re unsure about the compatibility.

Efficiency and Performance Implications

Changing the thermostat configuration may impact the efficiency and performance of your Lennox system. Be aware of the potential trade-offs, such as reduced efficiency or changes in heating/cooling stages, and weigh the benefits against the drawbacks.

Electrical and Safety Considerations

When working with electrical components, always prioritize safety. Ensure that you have the necessary electrical knowledge or consult a licensed HVAC technician to avoid any potential hazards.

Warranty and Manufacturer Recommendations

Before making any modifications to your Lennox system, check the warranty and manufacturer’s recommendations to ensure that you don’t void the warranty or compromise the system’s integrity.

By following the steps outlined in this guide and considering the additional factors, you can successfully override your Lennox thermostat and tailor your home’s climate control to your specific needs.


  1. Lennox EL296E Furnace Conversion Video
  2. Lennox Communicating to Standard Thermostat Conversion Discussion
  3. Lennox iComfort S30 Thermostat Reset Video
  4. Lennox Thermostat Troubleshooting Discussion
  5. Lennox iComfort to Nest Thermostat Replacement Discussion