Thermostat loses date/time and settings after a power outage.

Steps:

• Check for backup battery: Some models may have a small internal battery; if user-replaceable, install a new one per Rheem instructions.
• Enable cloud backup: Use the Rheem app to sync and back up schedules and settings where supported.
• Update firmware: Install any available updates that may improve power-loss behavior.
• If settings are lost after every brief outage: The internal memory or backup circuit is likely defective; thermostat replacement is recommended.