Completed furnace, maintenance and inspection. I cleaned flame sensor and wiped down furnace. I tested amp draws and components. I checked air pressure and temp splits. When I arrived, customer had some questions about the airflow and comfort of their home. After looking at the set up of the returns and vents, I was able to diagnose the issues they were having with comfort. The air pressure on their system is well over max. I explained how that can damage and shorten the lifespan of their system as well. We talked about options to correct the airflow, pressure and comfort of their home. I offered our membership as well. Furnace is operational at departure.