I replaced my 1/2 hp well pump a month ago, after over a decade of use. All seemed well until short cycling began. I hope I am using that term correctly. Essentially what is happening is the pressure switch cuts on almost immediately after a tap is opened and cycles on and off at a very rapid rate during the time the tap is open. When this first happened, i drained the pressure tank completely and checked the air pressure. Very high. Bled the air down to 38 (for a 40/60) and things seemed normal for a week or two. Then it did it again. Checked the pressure and same result. I've just bled off the pressure a second time....what is happening?
Your bladder has a slight leak, and water is leaking in to the airside, raising the air pressure. It will eventually fill with water, and you will see water coming out of the bladder when you attempt to bleed it down.