Indesit dishwasher overfilling

Question

My dishwassher is overfilling during the fill cycle, so that water pours from the overflows in the front door. I have checked the pressure valve and it is OK electrically. When it switches out (ie at correct fill level ) the machine just keeps filling. Can someone help ??
I have been told that some machines work on a timer fill not pressure....is the DG 6145 model one of these ?