York system retrofit in a 1970s ranch home. Removed outdated R-22 unit and installed a 16 SEER2 York single-stage AC with matched indoor coil. Brazed in new line set, pressure tested at 350 psi with nitrogen, and pulled vacuum to 500 microns. System charged with 6.2 lbs of R-410A. Total static pressure: 0.56 in. wc. System running clean.