E03 error and the Amfa4000 is stuck in regeneration or will not advance through stages

Safety first: Isolate electrical power and close the inlet and outlet valves. Place the unit in bypass to restore water to the home if needed.

• 1. Listen for motor operation: Restore power briefly and initiate a manual regeneration. Place your ear near the valve head. If you hear no motor noise at all, suspect the drive motor or wiring.
• 2. Inspect motor wiring: Disconnect power again. Remove the front/top cover of the Amfa4000 control head. Check the small motor harness plug is fully seated on the control board and that no wires are pinched or broken.
• 3. Check for mechanical obstruction: With the cover off, gently try to rotate the main cam or rotor disc by hand (if accessible per Amfa4000 service instructions). It should move with moderate resistance. If it is seized, internal valve components may be jammed by debris.
• 4. Test motor resistance: Using a multimeter (if you are competent to do so), measure the resistance across the motor terminals. An open circuit or very high resistance indicates a failed motor.
• 5. Replace the drive motor if faulty: Remove the mounting screws, swap in a new Amfa4000 valve drive motor, reconnect the harness, and reassemble the cover.
• 6. Reset and test: Restore water and power, clear the error by holding the reset button, and run a full manual regeneration to confirm the valve advances through all stages.

If the motor tests good but E03 persists, the control board or cam sensor in the Amfa4000 valve head may be defective and should be diagnosed by a professional.