I have well system and my water pressure will come on but then it will go to zero for a few seconds then it will come back on.I have a 30/50 switch,I hear no water draining and no water coming out of the valve stem. What do you suggest?

Assuming the pump cuts on at 30#, be sure your tank pressure is set at 28#. Turn off the power and drain water through a low-level faucet until pressure goes to zero. Then set the pressure using the air valve at the top of the tank.

Thanks for your reply, I have already done this and the pressure was at 28 psi... I raised the cut off/cut on switch 1/4 turn but the problem still exists. Could setiment build up where water goes into the tank restrict the flow of water as it draws down?

my water pressure will come on but then it will go to zero for a few seconds then it will come back on

Do you mean this happens when no water is being used, or water is being used? Do you know the pressure drops because of a lack of flow in the house, or because you are watching the gauge drop to zero? If you are not watching the gauge, then watch it once and see.

I don't think sediment is the problem.

Is your pump in the well or above ground?

Do you have a filter or softener on your system? If so, then try the bypass on that and see if the problem goes away.