I just got one of these today and the pressure regulator knob just bobbles around like an old jiggle top. It doesn't seem to make much difference whether it is pointing to lock, vent or neither. I've taken it apart and put it back together and I can't figure out any way to get it to go farther down into the handle. It blows enough steam out through the regulator that it never gets to pressure. Am I doing something wrong or is it defective? The floating valve seems to move freely, so I don't think that's an issue.