The problem seems to be air inside the system, that is between the cistern and the pump.
the pressure switch regulator is a 30 50 psi
the tank is a welXtrol pre inflated at 38psi without any water inside.
the pump works with 220 volts.
the pump is 1 hp and recently overhauled by an expert including bearings, seals and whatever was needed to put it back to specs.
So far noticed a drop of water down in the cistern coming from the pipe that sucks water . That is what makes me believe of air being trap in the pipe and or the impeller housing. but don't know how to prime it . please help.