Display shows E02 and the Aquabion softener remains in service mode without regenerating based on time.

Safety first: Disconnect power to the Aquabion softener before removing any covers.

• Verify power supply: Check the wall outlet with another device to ensure stable power. Inspect the Aquabion power adapter for damage, overheating, or loose connections. Replace the adapter if it is warm, buzzing, or physically damaged.
• Reset the controller: Unplug the unit for at least 5 minutes to allow the controller to fully discharge. Plug it back in and reprogram the current time, hardness, and regeneration schedule according to the Aquabion user manual.
• Check for firmware lockup: If E02 reappears immediately after reprogramming, the main control board real-time clock circuit may be defective. Some models allow a factory reset via a button combination; perform this only if you have the programming data available.
• Replace control board if needed: If the error persists and the time does not advance correctly, replace the main control board / timer module. This typically requires disconnecting all harnesses, labeling them, and transferring them to the new board in the same positions.

Warning: Working on the control board exposes you to mains voltage. If you are not comfortable with electrical work, contact a qualified technician.