Thermostat displays E07 and time/programming resets unexpectedly.

Safety first: Isolate power before removing the thermostat from its base or opening any covers.

Steps to check:

• 1. Confirm power stability: Ensure the boiler and receiver are not frequently losing power (check for tripped breakers or loose fused spur connections).
• 2. Replace user-replaceable batteries: If your Baxi thermostat uses AA/AAA cells, replace all batteries with fresh, high-quality alkaline cells, observing polarity.
• 3. Firmware update: If supported, use the Baxi app to check for and install firmware updates, which may correct memory handling issues.
• 4. Factory reset: Perform a full factory reset of the thermostat, then reconfigure schedules. Monitor if E07 reappears.

When to call a professional: Persistent E07 after battery replacement and reset indicates an internal PCB or backup power component failure; the thermostat head unit should be replaced.