This is a neat forum. I have a well pump for the house. Not sure if it is a jet pump or not, but I do know it is a centrifugul pump. It has been working great for years but recently the pressure switch is chattering when the pump kicks on. It does fine when shutting the pump off, but when the switch is suppossed to start the pump it "flutters" causing the pump to kick off/on very fast for half a second before finally kicking on. I just replaced the pressure switch, thinking maybe this was the problem, but it was not. The air pressure in the pressure tank is 38 and the pressure switch cut in pressure is approxiamatelly 30#. Any suggesstions?