i'm from philadelphia, pa.
does anyone know why economizer is require for certain building's RTU?
what exactly do you mean? why would anyone use an economizer or why is a particular unit in economizer mode right now?
Once you go black...you never go back to galvanized.
to bring a certain amount of fresh air into the building and for free cooling
min.outside air requirements & ability to have free cooling if needed
free cooling its always good to bring outside
air into the building
some places also require it to bring up your eer rating, depending on the equipment