E05 displayed and the softener regenerates at incorrect times or not at all.

Safety first: Only low-voltage circuits are involved, but unplug the unit before removing covers.

• Set correct time: Follow the Clearwater user interface to set the correct time-of-day and regeneration time. Confirm AM/PM settings.
• Check for frequent outages: If your home experiences frequent power loss, consider using a small UPS or surge protector to stabilize power to the softener.
• Factory reset: Use the controller’s factory reset procedure (often holding two buttons simultaneously for several seconds) to clear corrupted settings, then reprogram hardness, capacity, and time.
• Observe operation: After reset, monitor for 24–48 hours. If E05 returns or time drifts significantly, the Clearwater control board’s clock circuit is likely defective.

In that case, replace the Clearwater main control board; firmware updates, if available, should be applied by an authorized service center.