E13 displayed and the unit reports resin tank pressure anomaly during regeneration.

Safety: This fault can indicate dangerous pressure. Immediately stop the unit, close inlet, and relieve pressure by opening a downstream tap. Do not disassemble pressurized components.

• Verify valves: Ensure the outlet and bypass valves are in the correct positions for service. Do not regenerate with the outlet closed.
• Inspect drain and brine lines: Confirm both lines are clear and properly routed with no kinks or obstructions.
• Check piston movement: After depressurizing, remove the valve head cover and inspect the main piston/rotor for signs of sticking or damage. Clean or replace as needed.
• Test pressure sensor: If equipped, verify the pressure sensor is reading correctly. Replace if readings are inconsistent with actual pressure.
• Do not bypass safety: If E13 recurs after clearing lines and checking valves, contact a qualified technician. Do not attempt to override safety features.