Thermostat displays E14 and indicates an internal battery or backup power fault; settings may reset after power loss.

Safety first: Turn off HVAC power at the breaker before removing the thermostat from the wall plate.

• Step 1 – Minimize power interruptions: Ensure the furnace/air handler breaker is not loose and that there are no frequent power outages causing repeated drops.
• Step 2 – Reboot thermostat: Remove the thermostat from the wall plate for 60 seconds, then reattach. Check if E14 clears after a few minutes.
• Step 3 – Inspect PCB: With the thermostat removed, visually inspect the PCB for bulging capacitors or burn marks near the power section.
• Step 4 – Firmware update: Update to the latest firmware via the Geo app, as some versions improve power management.
• Step 5 – Replace thermostat: If E14 persists and the thermostat loses time/schedules after brief power interruptions, the internal backup component has failed. Replace the thermostat head unit.