E09 displayed and unit is stuck in regeneration, continuously backwashing or brining

Safety first: Immediately place the softener in bypass to prevent flooding or excessive drain flow. Unplug the unit.

• Inspect drain flow: Check the drain line for continuous flow. If water is constantly running to drain, keep the unit in bypass until repaired to avoid water waste.
• Check drive mechanism: Remove the valve cover and inspect the piston/rotor and drive linkage. Look for broken arms, disconnected pins, or obvious mechanical damage.
• Manual advance: With power off, attempt to manually rotate the cam to the service position. If it will not move, the internal piston/seal pack may be seized and require a Watersoft valve rebuild kit.
• Test position switch: Use a multimeter to verify that the position switch or encoder changes state as the cam moves. Replace if it remains open or closed in all positions.
• Control timing: If mechanical parts are free and switches work, but E09 recurs, the control board may not be advancing the cycle correctly and should be replaced.

Valve rebuilds involve depressurizing and partially disassembling the valve body; if unsure, contact a Watersoft technician.