Shallow well pump not building pressure past 30 lbs

[Cutlass72]

I just replace my shallow well pump at our cabin to fix a problem, but the issue remains with the new pump. Here’s the problem; the pump works fine, kicks in at 30 lbs, cuts out at 50 lbs (pressure switch is 30 - 50). But, if the pump sits without running for about 4 or more hours when it kicks in at 30 lbs it'll run without building pressure past 30 lb. If I turn the pump off, then back on, the pressure builds fine. The pump will continue to work properly until it sits idle again for an extended time. I’m out of ideas, any help would be appreciated.

 

[Valveman]

You are losing prime while it sits idle. If you use a foot valve before the pump and have no check valve after the pump, the water from the pressure tank will keep the pump primed during idle times.