Thermostat displays E13 and schedules or settings cannot be saved.

Safety first: Isolate power before removing the thermostat if inspection is needed.

Steps to attempt recovery:

• 1. Power-cycle: Turn off power for 2–3 minutes, then restore and try saving a simple schedule.
• 2. Factory reset: Perform a full factory reset from the settings menu. Reconfigure basic settings and test if they are retained after a power cycle.
• 3. Firmware update: If available, update to the latest firmware via the Baxi app, then test saving settings again.

When to call a professional: Persistent E13 indicates failing internal memory; the thermostat head unit will need replacement.