The well has no tank and just feeds a long one inch line with a shut off at the end. This configuration has worked fine in the past now when the well pump is powered up the switch goes into a rapid on off mode. The switch and the controller are new
Plumbing - Flotec - Well Pump Pressure Switch"
Answers & Comments
You are saying that the switch opens and closes fast? You need to put a pressure gauge on the line and see if it is bouncing up and down, If it is then we need to know what type make and model of pump you have on it.
IF you have a pressure tank on the line then it could be causing a surge from the tank pressure being too high. IF the air tank is a captive air tank with a bladder, the bladder might be leaking. The issue could also be air in the system. The electrical phase wont cause this.