Thermostat displays E8 and ignores user temperature changes or schedules.

Safety first: No high-voltage work is required. Avoid prying open the thermostat case.

Steps to address E8 memory fault:

• 1. Soft reset: Use the thermostat menu to perform a soft reboot. If not available, remove the thermostat from the sub-base for 30 seconds and reinstall.
• 2. Factory reset: Access the installer or advanced settings and perform a full factory reset. Note your system type and wiring before doing this so you can re-enter settings.
• 3. Reconfigure system: After a reset, carefully step through the setup wizard, selecting the correct Goodman equipment type (furnace, heat pump, stages, fan control, etc.).
• 4. Update firmware: Connect the thermostat to Wi‑Fi and check for firmware updates. Apply any available updates and allow the unit to restart fully.
• 5. Monitor operation: If E8 returns repeatedly after resets and updates, the internal memory hardware is likely failing.
• 6. Replace thermostat: Replace the thermostat with a new Goodman-compatible smart thermostat if the configuration cannot be saved reliably.