Furnace clean and tune. 1st year. Cycled system. Checked heat exchanger, ok. Checked, removed, and cleaned burners and flame sensor. Both ok. Checked igniter, ok. Checked and tightened electrical connections and clamps. Cleared drain lines. Found venting clamp incorrectly installed. Removed and installed correctly. Checked and adjusted gas pressures to maximize efficiency. Preformed combustion test and found normal levels in exhaust. No CO found in airstream. Replaced fi,yer. System operating normal at this time. Job complete.