Overfill condition; display shows E11 and machine may activate drain continuously.

Safety first: Disconnect power and close the incoming water supply immediately to prevent flooding.

Step-by-step checks:

• Verify water stops when power is off: With power OFF and water supply ON, check if water continues to enter the machine. If it does, the fill valve is mechanically stuck and must be replaced.
• Inspect overfill float: Locate the overfill or safety float. Ensure it moves freely and is not obstructed by debris or scale.
• Test overfill switch: Use a multimeter to verify the overfill switch changes state when the float is raised. Replace if defective.
• Check drain installation: Confirm the drain hose is not submerged in standing water and that there is no cross-connection allowing backflow into the machine.

When to call a technician: If the control board is energizing the fill valve continuously despite correct level signals, a board or relay fault requires professional service.