1 furnace pm check complete. Changed filter and added a nice citrus scent to it to bring extra freshness to the house! Did a combustion analysis and found good readings: 9.3% oxygen, 20 ppm co and furnace is operating at 97.4% efficiency. Tested mechanical and electrical components, all in good shape. Dusted out furnace cabinet and cleared barometric tubing. System heating normal at this time. Uv bulb is 2 years old, recommend changing bulb because they lose effectiveness after 2 years, customer did not want to do at this time. Renew cci plan.