E18 error; machine may not regenerate the built-in water softener correctly, leading to limescale issues.

Safety first: Disconnect power and close water supply before servicing the softener system.

• Check salt level: Open the salt reservoir cap and ensure it is filled with dishwasher-grade regeneration salt. Top up if low.
• Clean brine area: Remove any salt crust around the cap and inside the reservoir neck. Ensure the cap seals properly.
• Inspect softener valve: Locate the softener/regeneration valve assembly. Check for blocked hoses and ensure the valve coil is receiving power during regeneration (service mode may be required).
• Descale injector: If the model uses a venturi injector, remove and clean it to restore proper brine flow.
• Control check: If mechanical parts are fine but E18 persists, the control board may not be triggering regeneration correctly and may need replacement.