Display shows E18 and the Aquabion softener indicates a drain valve or drain flow error.

Safety first: Disconnect power and close inlet/outlet valves. Relieve pressure via a downstream tap.

• Inspect drain hose routing: Ensure the drain hose has a continuous downward slope to the drain, with no kinks or sharp bends.
• Check for blockages: Disconnect the hose from the control head and from the drain. Flush it with water to clear any sediment or scale. Clean the drain port on the Aquabion valve body.
• Test drain valve: During a manual regeneration, observe whether water exits the drain port freely. If not, the internal drain valve assembly may be stuck or worn and require replacement.

Warning: Ensure the drain terminates in an approved location with an air gap to prevent backflow contamination.