US Water Systems softener displays ERR3 and remains in service position, will not regenerate

Safety: Shut off water to the softener and relieve pressure before removing any plumbing connections.

• Locate the flow meter: On US Water Systems softeners, the flow meter is typically installed in the outlet or bypass assembly, with a small cable running to the control head.
• Inspect for debris: Remove the flow meter housing or turbine insert. Look for sand, iron sludge, or plastic shavings that may be preventing the turbine from spinning. Clean the turbine and housing with clean water; do not use harsh chemicals.
• Check turbine movement: Spin the turbine gently with your finger. It should rotate freely without sticking. If it binds or the shaft is worn, replace the flow meter/turbine assembly.
• Verify wiring: Inspect the flow sensor cable for cuts, kinks, or corrosion at the connector. Ensure it is fully seated on the control board.
• Test sensor output: With the unit powered and water flowing, some meters can be tested by measuring pulse output (consult the service manual). If no pulses are detected and wiring is good, replace the flow meter sensor.
• Reassemble and test: Reinstall the cleaned or new flow meter, restore water and power, and run water at a faucet. Confirm the display shows flow and that ERR3 clears.