Martin, I have seen the fault your discribing, but without more information I wouldn't like to comment to far.
Firstly, try confirming that the water is being pumped from the machine, this should be a fairly high flow rate. You can do this by placing the waste outlet hose in the sink, plug out of course. When the machine is empty there should be around about a coke can full of water remaining in the sump of the drum.
You say you've checked for blockages, have you cleaned the filter at the bottom of the drum? This is worth checking to make sure there are no obstructions in here.
Check these items and get back to me, I might be able to help.
Mike
November 2005
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