Champion dishwasher

we have a champion freestanding dishwasher at my church. after the cycle is completed, the pressure guage behind the washer still shows 25-30 and it contnues to spray water. not forced by the motor, but more like a stuck open fill valve. if i turn off the water and run it, then turn the water back on, the valve is closed and does not let water freely in. butif i run it with the water on, it will continue to spray in freely after the cycle light goes out and you open the door. i am an appliance technician, but i don't know much about the commercial stuff. any help is appreciated. thanks