zanussi dishwasher – model~:dws909 no fill??

hello,

there fellow repair engineers

i have a problem io hope some one can help me find the solution to i was called out to a zanussi dish washer model dws909 customer says “it wont fill”
put it on and surely enough the water valve is buzzing so i know there is juice there but “it wont fill”
after inspection i found the safety pressure pipe on the valve had triggered preventing the valve from opening.
straight away i thought ok so it must have triggered due to over filling so

i test pressure switch and clean all relavant pipes and advised customer it is all sorted 4 weeks later i get called out exactly the same fault.

i take the side chamber off to look a little deeper and cant find anything she tells me she did spill some rinse aid which i know can bubble up and over fill so i advise to try again (after pulling pipe off safety vavle)
4 weeks im there again!!!
i decide to collect it and run it in my unit to see what its doing basically it stops filling every say 6 washes.

im lost is there any pipes that block up on this model or some wierd and wonderful fault or have i just missed the obvious????

please help it would be much apprieciated

regards

mike

prod:911831019