I arrived on site and spoke brad and he stated they were getting a strong smell from the duct work. The smelling was like mold and damp is what Brad stated. I got on the roof and inspected the unit and I didnâ€™t find any water inside the unit or a smell inside the unit. After a couple minutes I did smell what brad was talking about but I was not able to pin point where the smell was coming from. But it was not from the rtu.