Furnace clean and tune. Cycled system. Checked heat exchanger, ok. Checked, removed, and cleaned burners and flame sensor. Both ok. Checked and adjusted gas pressures to maximize efficiency. Checked and tightened electrical connections and clamps. Cleared drain lines. Preformed combustion test and found normal levels in exhaust. No CO found in airstream. Replaced AA water panel. System operating normal at this time. Job complete.