We came into this problem after someone else replaced a burned out pump and could not get the pump back working.
Here is what we have:

PUMP SYSTEM : Myers Water Jet Pump RC5 - 1/2 HP - using 115 volt setting. New Pressure regulator. We got a new ejector kit / foot valve (R-E520-100) The ejctor's factory installed nozzle met the criteria of our well. We installed the recommended venturi tube. It is a two pipe system - 1.25" suction, 1" discharge. This entire system is new, top to bottom. New pipes, bibbs, nipples, clamps, air tank, etc. Two clamps and thread compound at each connection. We are using the "deep well" set up per the manual. Deep well criteria is: more than 25' to water. Well 30' to 60' deep.

WELL : 48' +/- deep bored well. 45' of piping from pump to foot valve. 10' of pipe in water. So approx 3' +/- water below bottom of foot valve.

The problem : Pump(s)-this is the 4th- primes ok. Builds pressure. The RC5 we have now is giving 38 psi and the pump is supposedly preset to cut off at 30 psi. Not one of the pumps would cut itself off. We had a Flo-Tec pump that gave 50 psi and would not cut off (although at that point we had some of the older pieces on the system). We swapped out pressure switches. We closed the valve feeding the house and still the pump held about 38 psi and would not cut off. We supplied the house with water from another well next door and that pump operated properly. The elderly couple there can turn the pump on and use water normally to bathe, wash clothes, etc. with normal water pressure. They just have to turn the pump off after each use. [:-(]