Control displays ERR 03 and will not accept programming changes; time and hardness settings may be lost.

Safety: Unplug the softener before removing the control panel. Avoid static discharge by touching a grounded metal object.

• Power cycle: Disconnect power for 5 minutes to allow the control to fully discharge. Plug back in and check if the error clears.
• Factory reset: Follow your Pentair model’s manual to perform a factory reset (often involves holding specific buttons while applying power). Re-enter time, hardness, and regeneration settings.
• Inspect connections: Remove the front panel and check the ribbon cable between the display/keypad and the main control board. Reseat connectors firmly.
• Check for moisture: Look for signs of condensation or water intrusion on the board. If present, correct any leaks from the valve or plumbing before replacing electronics.
• Board replacement: If ERR 03 persists after reset and wiring checks, replace the Pentair electronic control board with the exact model-specific part. Transfer any jumper settings as per the installation instructions.
• Test: Reprogram the unit and run a manual regeneration to verify normal operation.