The display shows E16, and the unit indicates an abnormal regeneration duration.

Safety: Disconnect power and close the inlet valve before disassembly.

• Check water pressure: Measure the inlet pressure at a nearby tap. Compare it with Grünbeck's minimum requirement (typically around 2 bar). Low pressure can prolong regeneration.
• Inspect injector and drain: Clean the brine injector and verify free flow through the drain hose, as described for brine and drain faults.
• Verify settings: In the installer menu, check that the resin volume, salt dosage, and regeneration times match the unit's type plate and commissioning sheet.
• Observe motor operation: During a manual regeneration, listen for pauses or irregular motor operation. If the motor stops unexpectedly, the drive assembly may need replacement.