Display shows “Err3” and regeneration stops at a specific step (e.g., brine draw or backwash).

Safety first: Unplug the unit and place it in bypass. Open a faucet to relieve pressure before removing any valve components.

• Inspect cam alignment: Remove the control cover and observe the cam and position indicator. Compare to the service manual positions (Service, Backwash, Brine Draw, Rinse). If the cam is not aligned with the indicated step, it may have slipped on the shaft.
• Check for broken cam follower: Look for a cracked or missing cam follower arm that engages the position switch. Replace if damaged.
• Verify rotor/valve movement: With the motor removed, gently rotate the rotor shaft through its full range. If it binds or stops abruptly, internal seals or debris may be blocking travel. Disassemble the valve stack and clean or replace seals and spacers as needed.
• Re-time the cam: Set the valve to the Service position manually, then reinstall the cam and motor according to Hellenbrand timing marks. Ensure the motor is fully seated and the cam set screw (if present) is tight.
• Test regeneration: Restore power, take the unit out of bypass, and initiate a manual regeneration. Watch the steps to confirm the valve now indexes correctly without returning to Err3.