<p>The method involves a circulation pump (7) to which liquid is supplied by sump well (11). Circulation pump is operated with lower and higher number of revolutions in first and second period. Level of water in sump well varies on the basis of speed. Circulation pump is operated in third period of working cycle in downstream stage with revolutions higher than first period but lower than second period. An independent claim is also included for dishwasher.</p>
