Display shows “Err 13” and unit reports sensor communication error

Safety: Disconnect power before accessing the control head and wiring.

Steps:

• 1. Identify sensors: On Sterling softeners, common sensors include flow meter, salt level, and position switch. Locate all harness connections to the main board.
• 2. Reseat connectors: One by one, unplug each sensor connector and plug it back in firmly. Look for bent pins or corrosion.
• 3. Inspect harness: Follow the wiring loom for cuts, pinch points, or rodent damage. Repair or replace damaged sections.
• 4. Dry moisture: If condensation or water has entered the control area, dry thoroughly and correct any leaks from plumbing above.
• 5. Replace board if needed: If all wiring checks out and Err 13 persists, the main control board may have a failed communication channel and should be replaced.