Dishwasher Zanussi ZT-695 will not start cycle?

When I start a programme it attempts to start but after a few minutes it stops and when I check the rinse hold light it is flashing rapidly. To remedy this I found i have to disconnect the water inlet pipe every time, pour water into the machine and it will start and finish the wash. Why do I have to keep doing this I have ran several cleaning programmes thinking it may be a blockage but it does not work.

Id be delighted with advice with this problem.

Thank you

Regards Mary