remove the filter at the bottom right.use a torch and look inside the filter housing where you have just removed the filter from.at the back you will see the drain pump impellor and you need to check if something has jammed it.use a long stick or screwdriver to make sure the impellor rotates freely.hopefully it is fluff around the impellor that has stopped it from working or something along those lines.
ck, March 2009