Display shows E01 and the Judo water softener does not start regeneration

Safety first: Close the main water supply to the softener and disconnect power before opening any covers. Depressurize by opening a nearby tap.

• Check inlet valve: Verify the house shutoff valve feeding the Judo softener is fully open. Many Judo cabinets have a bypass/inlet lever – ensure it is in the correct Service position, not Bypass or Closed.
• Inspect inlet strainer: Judo softeners typically have a fine mesh strainer at the inlet union. Close inlet/outlet valves, unscrew the union, and carefully remove and rinse the strainer under running water. Remove rust, sand, or limescale deposits.
• Check mains pressure: If you have a pressure gauge, confirm at least the minimum pressure specified in the Judo manual (often around 1.5–2.0 bar). Low pressure can prevent the valve from operating correctly.
• Test inlet solenoid valve: Restore power, initiate a manual regeneration, and listen/feel for the inlet solenoid clicking. If there is no sound and the control board is sending power, the solenoid coil may be open or stuck. Replace the Judo inlet solenoid valve assembly if it does not open when energized.
• Reset error: After correcting the issue, power-cycle the unit or use the control panel reset procedure from the Judo manual to clear E01.