1 furnace pm check complete. Changed filter. Did a combustion analysis on furnace and found high oxygen levels, recommend recalibration. Flue pipe is no longer up to code. Water safety is not up to code, recommend adding on. Static pressure is reading .96 w.c., that is a high level due to not enough return air. Recommend adding 12" duct to return for lower static pressure. Tested furnace components and all are in good shape. System is heating at this time.