Diplomat Adp 8322 dishwasher not cleaning the items. ?

I have a Diplomat ADP8332 dishwashwer which is not washing properly. I have cleaned and checked the filters and spray arms, checked it has enough salt & rinse aid & have the other temp setting with only few dishes in to check it is nothing to do with overloading, but to no avail. There are no lights flashing or codes lit to indicate a fault but each time i load the dishwasher and it completes a cycle the plates are still as dirty and the powder dispenser is open with most of the powder still in it! Water is coming through but i am not too sure how much ,
once the cycle is finished it is hot inside and so is the water. Any ideas would be great , before i pay for someone to come and fix???