I installed a new jet pump with a pressure switch which I do not know its ratings. I hooked it all up. It has a brand new flotec pressure tank. When you turn on the water inside the pump kicks on. THere appears to not be any water in the tank. It is a high pitch sound. At the beginning the pump just ran all the time. I unscrewed the nut in the pressure switch ( made it come up) and eventualllly it cut of. This is when it started running immediately after turning on the water. If you barely turn the water on inside it will start and stop very quickly. Any ideas. I thought about replacing the pressure switch with a new one. Is there a way to tell what kind of Pressure switch I have. Thanks

Thew very first thing you should do is install a replacement pressure control box, either 20/40 or 30/50.
To set the air pressure in a bladder tank, look at the cut-in pressure on your pressure switch. Now drain the line down with the pump off. When there is no more water coming out of the hose bib that you drained the system down with set the pressure in the bladder tank at 2 lbs. below the cut-in pressure. Check it with a tire gage. If your pressure control is set to come on at 20 PSI and go off at 40 PSI then your gage should read 18 PSI. If it kicks on at 30 and off at 50 the tank should have a PSI of 28. If you do all this your pump should work normally . Hope this helps and thank you for rating my reply.