I think I had the same problem, the pump shuttered and the electronic valve in the water hose opened and closed in time with the pump which created a violent on & off action. I fix mine by cleaning the water level switch. It's a screw out switch about 3-4cm across no the bottom of the unit, you will have to remove the drip try to get to it. you will have to push the black flexable hose to the side a bit to get the sensor/switch out. I just cleaned the goop out the the grill the 1st time and that didn't work so I had to completley disasemble it and wash the rubber diaphragm and grill separately, the washer works fine now.
hope this helps
Ben, March 2010
