5 Year old NEFF dishwqasher pumps continuously

[mojoworking]

Hi, when I turn on the dishwasher the pump runs and runs. I've checked the direction and it appears to be trying to pump water into the machine. It doesn't fill the machine with water, rather the pump keeps turning in the shallow bit of water that is left in dishwasher after each cycle. This first happened a few weeks ago so I followed some advice from the web and realised it was a float switch problem. I duly drained the collected water from the base of the dishwasher and that solved the problem.
However, a week later the same thing happened, so I drained the water out of the base again and the dishwasher worked. A few days later and the same problem has resurfaced a third time. Now I know that it's a problem with the float switch that is causing the base to flood. My question is, why does the floatswitch turn the pump on to clear the water from the base, which is outside the dishwasher cleaning compartment. Also, because this has happened three times now, is it definately a leak between the main compartment and the base, or could it be an issue with the outlet hose. I've also read that sometimes a blockage to the dishwasher outlet hose can cause a dishwasher to back fill with water. Would I be correct in assuming that this water would only fill the compartment and not migrate into the base of the machine?
Any advice would be greatly appreciated. Thanks in advance.
Dave

 

[Sleepyhead]

Water isn't pumped into the machine.
Is it the drain pump that's running all the time? or the wash pump?
If it's the drain then it has a flooded base which has activated the anti flood device.
Tip the machine backward about 45 degrees and the water should drain out of the base.

 

[mojoworking]

Thanks for the prompt reply sleepyhead. I've just checked and it is the drain pump as the base has got water in it. I've just drained it and the dishwasher is working again. Out of interest, why does the drain pump come on when the float switch is activated? I don't see how it can pump out water in the base of the machine in an area that is outside of the main dishwasher compartment.
Thanks again,
Dave

 

[Sleepyhead]

It can't pump water out of the base.
It's an anti flood device, designed to stop your kitchen flooding.
If water gets into the base it activates a switch that turns off the inlet valve and empties the machine. As it is still activated it keeps the pump running until it's reset (water drained out of the base).
Either a leak or overfoaming and flooding the base.
If it was backfilling it would fill the inside of the machine and then overflow into the base.

 

[mojoworking]

Thanks again sleepyhead for answering another of my questions. I understand now how it works and what is wrong. I think it is a foaming issue as the problem only started when I switched the type of detergent i use in the machine. I've been using FINISH tablets for years but recently switched to using powder, and that's when the problems started.
All the best,
Dave