Display shows “Err 03” and unit remains in service without regenerating

Safety: Shut off water and place the softener in bypass. Depressurize by opening a nearby faucet before removing any plumbing connections.

Steps:

• 1. Locate the flow meter: On Sterling Water softeners, the flow meter is typically mounted on the outlet side of the control valve or integrated into the valve body.
• 2. Inspect for debris: Remove the flow meter or turbine housing according to the service manual. Look for sand, iron sludge, or resin beads blocking the turbine.
• 3. Clean the turbine: Rinse the turbine and housing with clean water. Ensure the turbine spins freely with a gentle puff of air or light finger pressure.
• 4. Check the sensor and wiring: Inspect the Hall-effect sensor or reed switch on the flow meter for cracks or corrosion. Verify the wiring harness is intact and firmly connected to the control board.
• 5. Electrical test: With power restored and water in bypass, run water through the unit and use a multimeter (if experienced) to confirm pulse output from the sensor. If no pulses are detected, the sensor is likely defective.
• 6. Replace components: Replace the flow meter/turbine assembly or flow sensor if cleaning does not restore operation.
• 7. Clear error: Reassemble, take the unit out of bypass, and run water to confirm the display shows flow and Err 03 clears.