How to Fix / Troubleshooting

Safety: Unplug the unit and place it in bypass. Open a nearby faucet to relieve pressure.

Check for mechanical binding: Remove the valve cover and attempt to rotate the cam by hand. It should move with moderate resistance. If it is locked, the rotor & disc or seals may be seized.
Inspect for iron/scale: Look for heavy rust or mineral deposits inside the valve body. Clean with a soft brush and water. For severe iron fouling, consider using a resin/valve cleaner approved for water softeners.
Examine seals and spacers: Damaged or swollen seals can cause binding. Replace the seal & spacer kit if they appear distorted or torn.
Test motor separately: With the cam disconnected (if possible), briefly power the motor (following manufacturer instructions). If it does not turn, replace the drive motor.
Reassemble and test: Reinstall components, restore water and power, and run a manual regeneration to confirm the fault is cleared.

Display shows E4 and unit will not advance through regeneration

Possible Causes