hi some models you can chek the pump blades from inside if you take the filters out there is a cover held in by one screw if you remove this srew (usually a star haeded screw ) and lift up the cover you an check to see if something is blocking the pump if not flick the blades around to see if it turns ok if its stiff or broken it may need replacing the cover has to be efixed for the mahine to pump. If the pump needs changing remove the kick board then unscrew the small plate on the front of the machine and you will see the pump this usually just unlips and turns off, hope this helps
Darren
January 2009