E08 displayed and the unit reports a hardness sensor or quality sensor error (on models with integrated water quality monitoring)

Safety first: Isolate the softener and depressurize before removing any in-line sensors. Disconnect power.

• Locate sensor cell: Identify the Judo hardness or conductivity sensor, usually mounted in a sensor block on the outlet side.
• Clean sensor: Remove the sensor according to the manual. Soak the probe tip in a mild descaling solution (citric acid) to dissolve limescale, then rinse thoroughly with clean water.
• Inspect cable and connector: Check for cuts, kinks, or moisture in the cable. Ensure the connector is clean and firmly attached to the control board.
• Recalibrate: Use the Judo service menu to run a sensor calibration procedure, following the manual. You may need a hardness test kit to verify readings.
• Replace if necessary: If the sensor still reports unrealistic values or E08 remains, replace the Judo hardness / conductivity sensor.