If fluff collects in the bottom it will clog up the small opening to the back. At the back of the machine there is a small unit at the bottom, the condensed water flows in here and is pumped up to the top into the collections vessel. My drier (the same) got a hole in the filter allowing fluff in. If you take out the condensing unit at the front you can stick your hand in all the way to the back and try and clean it out, or try and prise off the back unit and take it out by hand
peter, July 2007