Hi Ian, I have done the things you suggested. All wiring seems to be fine. Started back to work this morning using cold water, I done the auto calibration, this came in at a desired calibration setting of 6 which I think is low and leaves very little room to re-calibrate should I use hot water. The pump worked fine for about half an hour and then the PS error came up and water flow stopped.
Does this sound like the pump is the problem? I think the pump is about 3 years old.