E9 error and the unit indicates abnormal inlet pressure or shuts down during regeneration

Safety: High water pressure can be dangerous. If you suspect excessive pressure, close the main stopcock and contact a plumber.

• Measure inlet pressure: Use a pressure gauge on a nearby tap to confirm that pressure is within the Tapworks recommended range (typically 1.4–8 bar; check your manual).
• Inspect inlet screen: Shut off water and relieve pressure. Remove the inlet connection and check the Tapworks inlet filter screen for debris. Clean under running water and reinstall.
• Check drain line: Ensure the drain hose is not kinked, frozen, or blocked. The end of the hose must not be submerged in standing water. Clear any obstructions.
• Verify bypass valves: Confirm the bypass is not partially closed in a way that restricts flow and causes pressure fluctuations.
• If E9 persists with correct pressure and clear drain: The internal pressure switch or sensor may be faulty. Replacement of the pressure switch or the complete valve head may be required.