Completed furnace, maintenance and inspection. I cleaned flame sensor and wiped down the furnace. I checked amp draws and tested components. I checked airflow and tested for carbon monoxide. The air pressure on the furnace is over the max rating for the furnace stated on the data plate by the manufacturer. Air pressure that is too high causes the system to work harder to move the air through the system and can wear down the system faster. It also causes the furnace to try and get air from anywhere that it can and since the furnace is in an attic, it will try to pull in the attic air and dust. Furnace is operating at departure.