Does anyone know what this is? It appears to be a manual blower fan that is attached to the main duct run at the top of the air handler. It has two flex ducts going to an unknown location on the second floor.
My guess is that it is a fan assist that helps pull the air up to the second floor. However, it is powered by a swith on the wall adjacent to the air handler, and only turns on when you flip the switch.
I have never come accross on of these, so I thought I would get your feedback.