E11 error and the display indicates a power supply or low voltage fault

Safety first: Unplug the power adapter before inspection.

• Check outlet: Verify the wall outlet supplies the correct voltage with a test device or multimeter.
• Inspect adapter: Confirm you are using the original Judo power adapter with the correct voltage and current rating. Check the cable for damage and ensure the plug fits snugly into the control head.
• Test with known-good adapter: If available, test the softener with a compatible Judo replacement adapter. If E11 disappears, replace the Judo power adapter.
• Board check: If a good adapter does not resolve the issue, the internal power regulator on the control board may be defective and the Judo main control board will need replacement.