Indesit D 4000 Dishwasher water inlet problem?

I purchased a D 4000 Indesit Dishwasher in the UK in 1997 and later moved to South Africa. It has worked very well until 2015. I then moved to the coast and had it in storage until now. After instaling it recently I did a run to test it with just water and all seemed to go well. Next with a small load I swiched on and found that the water kept filling and started to leak out of the machine door.
What part of the machine stops the inflow of water once it achives the optimum level as it seems to be where the problem lies. Please advise. Thank you