pump won't shut off

My well pump won't rise over 18psi. If I prime the pump and shut the valve between the pump and expansion tank and hold down the pressure switch I get up to 80psi then open the valve it drops down to 15 again. I have water with a lot of air and the pump won't shut off. I was wondering if there is...

We have a water reservoir with an electric valve that shuts-off when the reservoir reaches a preset level. When the electric valve shuts off, the well pump that feeds the reservoir should shut off, but it is not doing so. What kind of valve is needed to shut-off a well-pump? At the moment the...

We have a 4-5 year-ld Craftsman water pump (Model 390-252159) that supplies our water system. It has never given us much trouble, but all of a sudden it just won't shut off, even when it reads 70 PSI on the dial. I tried turning back the main screw on the top, thinking that might make it shut...

Hello, the pump located beside the gas heater comes on and off with the ac also but it won't shut off. What could cause this?

Jet pump won't shut-off. I just preplaced the pressure switch because it was leaking and now the pump builds to about 20lb and the pressure gage starts to bounce around. When the pump is unpluged the pressure in the pressure tank drops to 0. Pressure tank is 4 years old (air at 23 psi). I tried...