I have what I believe is a 150' well (early 70's install I think) with a 1 or 1 1/2 hp (label painted over) Sta-Rite multi (2) stage vertical pump on a 2" or 2 1/2" casing well with a non bladder pressure tank. I am not sure if it has a 1 or 2 pipe system inside the casing. For a while now when power is lost it will loose prime. Normally I can push a couple air bottles into it and it will prime as long as there is water in the tank. Other wise I stretch a hose for another source and let it sit over night and then it will prime.

A few days ago it was running and not hitting the upper shutoff, I replaced the pressure switch and it is still doing the same thing. I have tried all my usual tricks for three days and it still will not prime. The system will hold what ever pressure I put on it with the alternate water source and air applied to the top of the tank and will satisfy the pressure switch with air forced into the tank. When the pump runs it will make around 45-50 psi at the gauge on the pump regulator from 0 psi and add that amount to what ever pressure is on the system. I have ran the regulator up to max 100PSI starting at around 30 psi and down as far as it will go (cant remember)and still see not flow. The pump seems to sound like it is pump but not loading. It does not sound like it normally does when there is no water in the pump from what I can remember.