Had the same problem its going to be the reservoir at the back of the unit you will have to unplug the dryer take the lid of the dryer then the left had panel . Once this is of take out the filter and you should see into the reservoir at the back and it’s probably full of water and muck. first clean this out and check the small hole which leads through to the pump mine was blocked. You can also try talking the pump unit off the back which is secured by two clips on the back and two just inside , once this is gently taken off you can see where the pump sits this is probably full of much too so clean this out and re assemble the whole unit and test. I hope this helps
I am not an engineer so I cannot guarantee this will work for you and I am not responsible if you damage dryer.
Scott Lucas, September 2008
