Pkg clean and tune. Checked indoor coil. Cleared drain lines. Cycled system. Checked and cleaned electrical compartment. Capacitor tested lower, but in normal range. Contactor is ok for the time. Used coil cleaner on condenser coil. Hooked up gauges and checked pressures and temps. Both ok. Subcooling was 14, indoor coil was 45 degrees. Checked indoor temp split, found 18 degree split. System is operating normal at this time. Furnace clean and tune. Cycled system. Checked heat exchanger. Found all chambers had rust in them. No visible cracks found with camera. Checked and cleaned burners and flame sensor. Burners were very corroded. Flame sensor tested ok. Igniter has signs of being worn. Tested ok at this time. Checked and adjusted gas pressures to maximize efficiency. Checked CO and XS air levels in exhaust, normal levels found. No CO found in airstream. System operating normal at this time. Average life expectancy for both units is 14 years. Future failure is expected. Systems ope