40278 Water Softener Full Fix -

Once a year, let the salt run low and clean out the bottom of the brine tank to remove sediment.

Understanding the Meaning and Solutions for the "40278 Water Softener Full" Error 40278 water softener full

Open the small plastic tube inside the salt tank (the brine well). Pull the float assembly up. Ensure the float moves freely and isn't weighed down by salt buildup or debris. If the float is stuck, the system won't know when to stop filling. Once a year, let the salt run low