Zanussi Not Draining

[Mr Wash]

Zanussi ZWF 1421W, 10 yrs old.

A few years ago it started to fail to drain, warning light and flashing. I did a manual drain, after which the cycle continues.

It got more and more frequent. I found the sump float ball gunged up with grey slime, after cleaning this out, all went well for a while.

Now it's happening almost every wash.

The pump still works, but something is telling it not to run, and I'm not sure what. Could it be to do with the float not dropping down? Does the pressure switch influence whether the pump will run or not?

Hope this is clear, hopefully someone can help me understand!

Many thanks.

[Whitegoodshelp]

Have you read my comprehensive advice on Washerhelp about washing machine's not draining the water and all the links within it? I've removed persistent gunged up sum hose balls before, they don't affect the function of the machine, their purpose is just to shut off the sump area to prevent detergent going in there when it first gets flushed into the machine. Especially if you use tablets or a dispenser of detergent on top of the laundry you shouldn't even need one. Washers worked fine without them for decades before someone thought of it.