new member needs some info. I opened my friends pool last week. the p4 aqua logic system displayed sys chk - no flow immediately after powering unit. after confirming flow on pressure gauge, fully primed pump and return jets i waited to see if message disappeared. did not. eventually removed flow switch and checked flapper for corrosion, damage, obstruction etc. not so much. looked like new. replaced switch and made sure it was aligned properly etc. l.e.d. message and indicator light went off. my friend called me recently and said that the message has re-appeared and his pump has turned off intermittently since. I did not ask if it has turned off outside the timer programming but the flow switch is solely designed to prevent chlorine build up when pump is not operating by cutting cell correct? should have no effect on pump operation? i am going to attempt to by-pass the switch to confirm its faulty but am confused by the pump situation.