Check the filter in the bottom of the machine, (If it has one), and make sure it's clean. Shine a torch into where the filter goes and you will see a small impeller, (looks like a small orange squeezer). Use a pencil to manually turn the impeller and see if it is chocked with grit or wet sludge. If it moves freely, the outlet pipes may be partially blocked. Check the flexi and the outside draining waste pipe and clear if nescessary.
Davy Mac, June 2009