I usually hold it down a little bit. It will allow for the small air pockets to escape from under the head. Look with a flashlight at the top section and you may see a water line/air section. I purge it slightly with the prime button, this brings all the gurgling air bubbles out of the head unit where the impeller is at. You may always get some air streams out of the outlet bar when you press the prime button down slightly, but you should be able to get all the noisy air pockets out. As for my 2028 unit, I can't hear anything. Maybe if the room was empty and it was the only thing on, I still would have to put my ear next to it to hear it running. *crazysmiley*