Display shows “Err 4” and regeneration stops during brine draw or slow rinse

Safety: Bypass the softener and depressurize before opening the valve body.

• Clean injector and screen: Remove the injector/nozzle-venturi assembly from the Autotrol valve (usually under a cap on the side or top). Take out the injector and screen. Soak them in vinegar or a mild acid cleaner to remove iron and scale. Rinse thoroughly and reinstall.
• Inspect brine line: Disconnect the brine line from the valve and brine tank. Blow through the tubing or flush with water to ensure it is clear. Replace the brine line tubing if kinked or brittle.
• Check brine valve: Inspect the internal brine valve (or brine piston) for sticking or debris. Clean the valve bore and replace the brine valve assembly or brine piston and seal kit if worn.
• Verify brine level movement: During a test regeneration, watch the brine tank. The brine level should drop during brine draw. If it does not, re-check injector orientation and all connections.
• Clear error: After cleaning and reassembly, restore service and power, then run a manual regeneration to confirm the error clears.