Thermostat display shows E01 and will not connect to Wi‑Fi or the Geo mobile app.

Safety first: Turn off power to the HVAC system at the breaker before removing the thermostat from its wall plate. Low‑voltage circuits are present but can still cause damage if shorted.

• Step 1 – Reboot thermostat and router: Remove the Geo thermostat from its wall plate for 30 seconds, then reattach. Power‑cycle your Wi‑Fi router for 60 seconds. After both restart, try reconnecting via the Geo app.
• Step 2 – Verify network type: Ensure your router is broadcasting a 2.4 GHz network with WPA2 security. Geo smart thermostats typically do not support 5 GHz‑only or enterprise networks. If needed, create a 2.4 GHz SSID.
• Step 3 – Reset network settings: From the thermostat menu, navigate to Settings > Wi‑Fi > Reset Network (wording may vary). Confirm reset, then re‑enter your Wi‑Fi credentials using the app or on‑screen prompts.
• Step 4 – Check signal strength: Move your router closer or remove metal objects between the router and thermostat. In the app, check RSSI or signal bars; if signal is weak, consider a Wi‑Fi extender.
• Step 5 – Inspect antenna and PCB: With power off, gently pull the thermostat off the wall plate. Inspect the Wi‑Fi antenna lead (small coax or flat antenna strip) on the main control board for disconnection or visible damage. Reseat any plug‑in antenna connector.
• Step 6 – Firmware update: If you can briefly connect, check the Geo app for a firmware update and apply it. Firmware can resolve corrupted network stacks.
• When to stop: If E01 persists after network reset, router checks, and antenna inspection, the Wi‑Fi radio on the main PCB is likely failed and the thermostat head unit should be replaced.