Control panel shows E01 and the softener does not start a regeneration cycle.

Safety first: Disconnect the softener from mains power before removing any covers. Water softeners are often installed near damp areas; ensure the area is dry and stable before working.

• Power reset: Unplug the unit or switch off the dedicated breaker for 5 minutes. Restore power and check if E01 clears.
• Inspect control wiring: Remove the front cover of the Hansgrohe softener head. Locate the low-voltage harness between the display module and the main control PCB. Check for loose plugs, bent pins, or corrosion. Reseat all connectors firmly.
• Check for moisture: Look for signs of condensation or water ingress around the control housing. If present, dry the area thoroughly and correct any leaks from nearby plumbing before re-energizing.
• Board inspection: With power still disconnected, visually inspect the main PCB for burn marks, swollen capacitors, or cracked solder joints. If any damage is visible, the board should be replaced as a complete assembly.
• Restore power and test: Reassemble the cover, restore power, and attempt to start a manual regeneration. If E01 persists after wiring checks, replacement of the main control board is recommended and may require a qualified technician.