E19 error and the unit indicates simultaneous conflicting valve positions

Safety first: Disconnect power and place the softener in bypass before working on the control head.

• Inspect cam and sensors: Remove the control cover and observe the cam and all position sensors. Ensure only one sensor is actuated at each cam position. Adjust sensor mounting if two are engaged simultaneously.
• Check for shorts: Examine the sensor wiring harness for crushed or abraded sections where wires may be shorted together. Repair or replace as needed.
• Clean cam surfaces: Dirt or burrs on the cam can cause unintended sensor activation. Clean the cam and lightly deburr any rough edges.
• Reset control: After corrections, restore power and allow the unit to home. If E19 clears, run a full regeneration to confirm that sensors change state correctly through all stages.

If E19 persists despite correct mechanical alignment and wiring, the control board sensor inputs may be damaged and the board should be replaced.