What does the lock icon on my S40 Smart Thermostat mean?
FAQ , Thermostats , Troubleshooting Modified: March 19, 2026
Having a lock icon on your thermostat means you're restricted from certain features. There are two types of lock screens: "Partially locked" and fully "Locked".
For more information or a visual representation of steps please reference our user guide here
Find a Local Pro
Enter your zip code to find a Lennox® dealer near you for service, support, or installation.