I just flushed my fresh water system this weekend and the pump does not shut off after all the facets are closed like it usually does. There does not appear to be any leaks that I can detect (no water dripping from connections). The pump itself is original (28 years old) and has been getting louder and louder that last few years. I realize that if you have an air leak anywhere in your system the pump will continue to run as it cannot hold the pressure. Pressure at the faucets appears to be fine. The question I have is where is the pressure sensor which tells the pump to turn off? The pump is a Jabsco. I am assuming the pressure shut off switch is built into the Jabsco pump or is it typically separate? Given the age of the pump and that it is so loud, I will probably replace it anyway but just wanted to double check before replacing the pump that the pressure shut off is a built in function of the pump and may have just gone bad over the winter.