bladder tank and zero psi when valve open

[elizasue1]

I have a bladder tank with a pressure switch set to 30-50 psi. With power on and all valves closed, the gage shows 50psi. We fully opened the 1-1/4" ball valve so we could time the pump on/off cycle because we had concerns about the 45 gpm pump capacity and a 50gal total volume tank (~15 gal drawdown) and burning up the submersible pump motor. After more than 1 minute the pump was still running, so we looked at the pressure gage and it was at zero psi. We closed the ball valve and within 10 seconds the pump turned off and the pressure was back to 50psi. This system is new so what should I be looking at to fix?

 

[IceStationZebra]

First the obvious - charging a dry 50 gallon bladder tank with a 45gpm pump is probably going to take over 1 minute.

Something down stream is using all the water that you can pump. You are only going to build pressure if there is some resistance to flow. And the bladder tank (an accumulator) can only reach the same pressure as the pipe just down stream.

ISZ