I have a wellsaver 12 gallon tank mounted next to pump for a shallow well irrigation system. When the pump is running I can get water out but the pressure will not build up in tank enough to cut off pump which is set about 40psi. There is only air that is released from Shredder valve when depressed and I have plenty of air pressure applied to tank. I don't think it's a pressure switch problem and I know water is being pumped because of the amount of water coming out of hose bib mounted in piping next to pump.Its not great pressure but it should be enough. It seems as though the water pressure is not being increased enough by the pressure tank. I would appreciate any trouble shooting tips.

The air pressure in the tank should be set at 2psi below your cuton pressure, For example, if you are set to cut on at 20psi and off at 40psi your air pressure in the tank should be 18psi.

"It seems as though the water pressure is not being increased enough by the pressure tank."

Woodman, you have a pump problem. We get this same complaint from time to time here. Pressure tanks do nothing but store water under pressure which is generated by the pump. In your case the pump is evidently not able to produce enough pressure to reach cut off pressure. Having stated that, I am assuming that your pump will not reach cut off pressure even when no water is being used. In other words, it will sit there and run a couple of hours and still not get to 40#, the cut off pressure. Is that correct? If so, then the problem will generally involve the pump. With only a 12 gallon tank, you should be able to get to 40# and shutoff in a matter of a few minutes.