Ok lets see if I can help you on this, the first thing I think of is a restriction to flow if I get higher than normal reading on the high side, But first I have to no if the system is over charged. This is when I bring the sight glass into play as I charge the system I look for very slow or even no movement in the glass, of course it is moving along at its normal flow rate but as the airated bubles go away it looks like things are standing still. Now high pressure could also come from contaminated freon, water the dryer, may be in need of replacement. I hope I have helped you a little, I know you have given me great info. By the way I converted all of our units to freez12 it has propane in it and not every one carries it but it sure is cheaper than the old 12. JNT