E16 displayed and the unit reports a drain line or drain valve error.

Safety first: Unplug the softener and close the inlet valve. Expect water in the drain line.

• Inspect drain hose: Follow the drain hose from the valve to the drain point. Remove any kinks, loops, or sags that can trap debris. Ensure the hose is not longer or higher than AquaSoft specifications.
• Clean drain flow control: At the valve drain port, remove the drain elbow and flow control insert. Rinse out any iron or sediment buildup and verify the orifice is clear.
• Check drain valve piston: Access the drain valve piston or spool inside the control head. Remove, clean, and lubricate O-rings with silicone grease, or replace the piston assembly if worn.
• Test drain flow: Reassemble, open the inlet valve, and initiate a manual backwash. Confirm a strong, steady flow from the drain hose and verify that E16 clears.