Dishwasher only filling for a short time - HELP!!!

Hello all, I'm a bit stuck with a dishwasher problem. I've just got a second-hand Zanussi Aquasave DW917.

When the cycle begins, it begins to fill, then stops after about 10-15 seconds. the programme starts, but there does not seem to be enough water in the base, the arms arn't spinning and the exposed eliment in the base of the machine is getting VERY hot.

The feed and drain hoses are both clear and it is pumping out ok, when filled with an extra couple of jugs of water?

Any ideas would be great!!!

Thanks for your help, in advance,

Rob.

Check the pipework from the pressure switch back to the bowl of the machine. If it's the "blue tubes" inside the cavity take them out and clean thoroughly. Could possibly be a faulty pressure switch.

Thanks sleepyhead, i'll give it a go, and let you know.