Display shows E4 and the unit does not measure water usage correctly

Safety first: Shut off inlet and outlet valves and relieve pressure before removing any flow meter components.

• Check for debris: Many BWT softeners use an inline turbine flow meter on the outlet side. Remove the union fittings and carefully extract the turbine. Rinse under clean water and remove any grit or scale.
• Inspect turbine: Ensure the turbine spins freely with a gentle puff of air or by flicking it with a finger. If it sticks or is worn, replace the turbine assembly.
• Verify sensor connection: Follow the cable from the flow sensor to the control board. Confirm the plug is fully seated and there is no visible damage to the cable.
• Clean housing: Wipe the inside of the flow meter housing to remove sludge or iron deposits that could impede movement.
• Reset controller: After reassembly, restore water and power, then reset the controller and run water at a tap to confirm that flow is being registered.

If E4 remains, the Hall-effect sensor or main control board may be defective and should be tested or replaced by a professional.