Try to drain machine by running the outlet pipe into a bucket.
Check the filter unit for blockages.
Disconnect pump from sump hose and check for obstruction in either item.
Pump removal: power off, remove cover, locate pump, undo 2 wiring connections, 2 hose connections, and pump mounting screws.
Check out my site for info: www.2ndwave.co.uk/manual.html
washerman
March 2008