I was given this washer as a back up,the lady told me it is 3 years old.A couple days ago she said she was washing and the fill station would not stop filling.I thought it was from hard water build up.I took apart where the water lines go and there was alot of build up on the sensors would that cause this problem?

Well was the washers old owners place have clean water also?If it was a white build up if yes i would if not it can also be build up in the small water tube going from the tube to your fill switch the water level control.Sorry almost forgot to mention that also could be the problem hope i helped:) Well was the washers old owners place have clean water also?If it was a white build up if yes i would if not it can also be build up in the small water tube going from the tube to your fill switch the water level control.Sorry almost forgot to mention that also could be the problem hope i helped:)