Furnace start up. Cycled system. Checked gas lines for leaks, none found. Checked venting and drain line. Ok. Checked incoming and outgoing gas pressures. Adjusted gas pressures to maximize efficiency. Checked electrical connections and clamps. Tested levels of CO and XS air in exhaust, normal levels found. No CO found in airstream. Tested temp rise in low and high fire rate. Both were normal. Minimal adjustment needed. System operating normal at this time. Job complete.