Display shows E6 and the unit reports abnormal water temperature or shuts down

Safety first: Turn off power and water. Allow hot water lines to cool before working on the unit.

• Locate sensor: On models with integrated temperature monitoring, the NTC sensor is usually clipped into the valve body or outlet manifold. Refer to the BWT schematic.
• Check wiring: Ensure the sensor plug is firmly connected to the control board and that the cable is not pinched or cut.
• Inspect for overheating: If the softener is installed on a hot water line (incorrect installation), the sensor may have been damaged. BWT softeners must be on cold feed only.
• Replace sensor if needed: If the sensor body is cracked, discolored, or reading erratically (if you can measure resistance), replace it with the correct BWT NTC sensor.
• Reset alarm: After correcting the issue, power-cycle the unit and clear the error via the menu if required.

Persistent E6 after sensor replacement indicates a possible control board fault and requires professional diagnosis.