Down at the very bottom on the inside there's a sump - clear out the water and remove the single screw that holds down the plastic cover - there will very probably be crud - lemon pips - foil and other stuff stopping the pump's impeller from working properly - the blades of the impeller should rotate freely but with a bit of magnetic resistance.
You may need a Torx driver to remove the screw - ask a friend. You may need tweezers to pick up the crud.
Good luck...
Ben Dix, October 2014