Hi all, I'm in the process of parts ordering for a sanitation system overhaul. On my system currently, the pump will sometimes run forever, and sometimes shut off like it should. I suspct that the pressure switch is not working properly. Is there an adjustment on the switch? I have to dismount my vacuum tank to get at the switch so I haven't really done much investigation yet. should I just plan on replacing the switch or do these typically last a long time?