Question
My aunt has this model , its been in the house for 16 years. One of her stations will not turn off. we have to turn off the main water valve to stop it from running . What can we do.?

Answer
It is more likely a problem with the valve than with the controller.  Try adjusting the valve as follows:
locate the valve and expose it, on top of the valve there will be a knob that controls the flow control, turn the flow control all the way clockwise until it is off, then all the way counterclockwise while counting the number of turns, then turn it back clockwise 1/2 the number of turns.  This is the correct adjustment for most valves.