Display shows “Err 10” and the unit may be stuck in a regeneration step for an unusually long time.

Safety first: Unplug the softener and place it in bypass before opening the valve head.

• Observe where it stops: Note which step of regeneration (backwash, brine draw, rinse, refill) the unit is stuck in when Err 10 appears. This can help pinpoint the mechanical area causing drag.
• Inspect rotor and seal kit: Remove the valve cover and pull out the rotor and seal kit. Look for deep grooves, swelling, or hardened seals that could increase friction. Replace the rotor and seal kit if worn.
• Check for debris: Inspect the valve body ports for sand, resin beads, or scale buildup. Flush out any debris with clean water.
• Test drive motor: With the rotor removed, briefly power the unit and start a manual regen to see if the drive motor turns freely without load. If it stalls or is intermittent, replace the motor.
• Control board timing: If mechanical components move freely and the motor is good, but the unit still times out, the control board may not be correctly sensing position or timing steps. Replace the electronic control board if needed.