The 6 was on the liquid line.
The reason for the question was I started 15 New York pkg 3:4/5/6 tons and my pressures were all over the place.and so was my sh/ sc. I understand the variables but I would think they would be some similarity,
Even though the units are all similar / same, the loads, ductwork, quality of insulation on linesets, amount of construction debris on evaporators, accuracy of the charge, condenser airflow, etc... may all be quite different.
How are you attaching your gages? Do you have to remove a panel? If so, How well is the hole (if it exists) blocked up? You could have very different condenser airflow each time....any flow that goes through your access to the compressors instead of through the coil will mean a little higher discharge pressure and a little less subcooling...
The compressors sit in the access panel/ control panel no air flow issues. The only available ports are at the compressors. No coil air flow can be changed. I just think mfr charge isn't as exact as they want us to believe.