Display shows E3 and unit remains in one position of the cycle (e.g., stuck in backwash or brine draw)

Safety: Disconnect power and place the unit in bypass before disassembling the valve.

• Check cam alignment: Remove the valve cover and verify that the cam is properly aligned with the rotor & disc. Look for signs of the cam slipping on the shaft.
• Inspect position sensor: Some WaterBoss models use a small sensor or switch to detect cam position. Ensure it is firmly mounted and the wiring is intact.
• Look for stripped gears: Rotate the cam by hand (with power off). If it spins freely without moving the rotor & disc, the gear may be stripped and require replacement.
• Clean and re-seat rotor & disc: Remove the rotor & disc assembly, inspect for scoring or debris, clean with water, and reinstall carefully, ensuring the seals are seated.
• Re-test: Restore water and power, then initiate a manual regeneration. If E3 persists, the encoder/position sensor or control board may need replacement.