Display shows Err8 and unit locks out regeneration cycles

Safety first: No internal electrical work is required for this procedure, but do not open the control housing while powered if you are not trained.

Step-by-step checks:

• 1. Review programming: Enter the installer or advanced menu per the Marlo manual. Verify that the resin volume, hardness, salt dosage, and meter type are set correctly for your specific Marlo softener model.
• 2. Restore factory defaults: Use the factory reset function (if available) to reload default parameters. Then re-enter site-specific settings.
• 3. Check meter type: Ensure the selected meter/turbine type matches the installed hardware (e.g., 3/4" turbine vs 1" turbine). A mismatch can cause Err8.
• 4. Power cycle: Disconnect power for 2–3 minutes, then restore. Confirm whether Err8 clears after correct programming is stored.

When to replace parts: If Err8 persists despite correct programming and resets, the Marlo control board memory may be corrupted and require replacement.