Hi, it's normally fibres trapped in the filter.
Unplug the machine, disconnecting the water, (switch of at valve first) unscrew the back of the machine.
There should be a large black pipe with a clip around it. Undo the clip, pull out the filter, clean and replace it all back, Job Done.
P.S. Just thought, if you can't hear the pump trying to empty it, it's probably the pump instead.
Hope this Helps,
Simon.
Friendly Simon., March 2008
