I have a watersoftener with a fleck 9500 head that intermittently doesn't regenerate. The problem is the dial with the numbers that counts the gallons used, counts down to zero then past zero and then somehow goes overtop of the other dial that it is suppose to be turning to start the cycle. When this happens the dials just get jammed up until I physically turn the dials back to where they will regenerate. Any ideas what is causing this?