Control shows “Err 3” and unit remains in service position without regenerating

Safety: This is an electronic fault. You will not be opening pressurized plumbing, but unplug the unit before removing the control panel.

• Soft reset: Unplug the softener for 5 minutes, then plug it back in. Re-enter the time of day and hardness settings according to your Culligan manual.
• Verify model settings: Enter the installer menu (refer to your specific Culligan model manual) and confirm the correct softener size, valve type, and regeneration mode are selected.
• Check for surge damage: Look for burn marks or a burnt smell on the control board. If present, the board must be replaced.
• Hard reset (if documented): Some Culligan controls allow a factory reset via a button combination. Only perform this if you have the programming data (capacity, salt dosage, etc.) available to re-enter.

If Err 3 persists after reprogramming and power cycling, the control board is likely defective and should be replaced by a professional.