the water will not empty from the drum?

The water will not empty from the drum. I have used the emergency pipe to empty the water out and I have cleaned the filter (not much there, just a very little fluff). I have run a few different programmes, but it still will not fully empty, the second time a little more fluff. I have only had the machine since June 2011, therefore only 2 years. Previously, the under the sink outlet was cleaned.