Hi I have a cottage with a shallow well with a sand point .I have a 1/2 H.P. jet pump that draws the water and is connnected to bladder tank which is about 30-40 gallons, (it stands about 3 feet high) The problem is it won't turn on without first giving the pressure relif valve a couple of raps with a paint handle. It then fills the tank and kicks out Ok but when the water is gone you have to rap it again. Is that a problem with the pressure switch? and if so what size switch should I use?

Thanks for any help you can give me . I'd like to fix it myself if possibe before I call a well guy in.