What i'm saying is your getting air in the system. Unless any components is above 28 feet, assuming your system is at 12psi or greater, you are going to leak water not suck air into the system. So the only other way air gets in the system is from makeup water or osmosis through the walls of the non ferrous components of the system. With half way descent air elimanator the osmosis is no problem. But with sustain makeup water, lots of time the air elimanation can't keep up. The oxygen will go to the highest point of the system. If that highest point of the system isn't run through the air elimination it will slow act like a air custion and prevent the water regulator from filling, hence the pressure is ok.
I hope you are following this. lol