Thermostat displays E5 and Wi‑Fi or smart features are disabled

Safety first: No high-voltage work is required for this fault, but avoid opening the thermostat beyond the user-removable front cover.

Steps to address E5 Wi‑Fi fault:

• 1. Reboot thermostat: Remove the thermostat from its sub-base for 30 seconds (or use the reset/reboot option in the menu), then reinstall and allow it to fully boot.
• 2. Forget and re-add network: In the thermostat's Wi‑Fi settings, select your network, choose "Forget" or "Remove", then re-scan and reconnect, entering the correct password.
• 3. Check router settings: Ensure your router is broadcasting 2.4 GHz (if required by the model), with WPA2 or WPA3 security. Disable MAC filtering or add the thermostat's MAC address to the allowed list.
• 4. Reduce interference: Move high-power Wi‑Fi routers, cordless phone bases, or microwave ovens away from the thermostat wall if they are very close. Avoid metal wall plates that can shield the radio.
• 5. Factory reset: Perform a full factory reset of the thermostat from the installer menu, then reconfigure system type and reconnect to Wi‑Fi.
• 6. Replace thermostat: If E5 persists after reset and the router is confirmed compatible, the Wi‑Fi module on the thermostat is likely failed and the thermostat should be replaced.