Display shows “Err 08” and the softener will not recognize when the brine tank is refilled or when regeneration completes.

Safety first: Disconnect power before working on the valve head.

Check regeneration settings:

• Verify hardness, capacity, and regeneration time are correctly programmed according to the AO Smith manual.
• Ensure the regeneration type (metered vs. time clock) matches the installed valve.

Inspect mechanical feedback:

• Remove the cover and observe the cam/rotor and position switch/encoder.
• Run a manual regeneration while watching the cam move through each step. Confirm the valve completes all positions and returns to service.
• If the valve stops mid-cycle or never returns to service, inspect the drive motor, gears, and position switch for damage or misalignment.

Corrective action: Repair or replace the drive motor or position switch/encoder if they fail to signal completion. If mechanical parts are working but the error persists, replace the control board.