E07 displayed and the unit overfills the brine tank or drains continuously during regeneration.

Safety: Unplug the unit and close the inlet valve. Place towels or a shallow pan near the drain connection to catch water.

Steps:

• Inspect drain line: Ensure the drain line is not routed too low or creating a siphon effect. The end of the drain line should be above the drain trap and have an air gap.
• Check for constant drain: With water on and unit in service, listen at the drain. If water flows constantly, the internal drain/brine valve is likely stuck.
• Disassemble valve head: Remove the valve cover and access the brine piston and seals. Inspect for debris, scale, or torn seals.
• Clean and lubricate: Clean all parts with water, remove debris, and lightly lubricate O-rings with silicone-based lubricant approved for potable water.
• Reassemble and test: Reinstall components, restore water and power, and run a manual regeneration to confirm proper fill and drain operation.

If the problem recurs or seals are visibly worn, install an AquaClean valve seal and piston kit.