How do I unlock the Lennox S40 Smart Thermostat display?
FAQ , Thermostats , Troubleshooting Modified: March 19, 2026
When the thermostat screen is locked, the lock icon appears on the home screen. To unlock the screen, just press and hold the lock icon
Once your screen is unlocked, everything should return to normal and allow you to change set-points, mode, etc.
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