Ariston margherita flashing 10 times dial rotating continuously?

Hi, please can anyone help us? our ariston margherita A 1435S is flashing 10 times with continuously rotating dial at softener intake (but first wash of the day is fine). Are we right in thinking the pressure switch is not sensing properly? if so what to do and where is it please or is it likely there is a leak onto the main board or something that dries out overnight thus making the first wash ok? P.S Does anyone know of a site where we can look at exploded diagram please?

Lisa and Geoff
January 2007