Have a 5 yr old shallow well in basement. Flo-Tec FP4322-08 with shallow well kit. 1 1/4" pipe (36" point) is at 26' 2" from pump intake. Static water level is 15' 5" from priming tee at pump inlet. . Screen purged with 4 gal. of vinegar overnite twice. Water runs down pipe like a "rathole" with a garden hose after the purging. Still can't get a prime! There is a vacuum on the pipe when taking out the priming plug, so I believe there are no air leaks. Is the pump worn out or what? Could just a couple of summers worn this thing out? Need some help here!