Hi, got a Hotpoint DWT10 dishwasher, and it won't cycle through fuly -
any ideas?

Water flows in, and will pump out - so that's all okay. The main pump
works when I put 240 to it, so that's okay. The pressure switch seems
to work okay. But when I run a cycle, water flows into the dishwasher
bay, gets maybe half an inch deep, and then pumps straight out again.
Hotpoint are useless - says the flashing eco and prewash light means a
filter problem - but the filters are clean, and so is the drain pump.
As well as a pressure switch there is a weird container, with some kind
of switch on it, that appears to run off a hose coming from the sump -
I think this might be an addtional level swtich - a venturi perhaps?

I know nothing about this thing, so any advice would be most grateful.
Hope you can help fellers.