The Turn Room Layers On command turns the room outline and room label layers on. These layers are typically on a non-plotting layer that will not appear on your printed drawings. It is often helpful during the design to turn these layers on and off to see what your final drawing will look like.
To turn the room outline and room label layers on, go to
Ribbon: DM HVAC->Rooms and Walls-> 
Turn Room Layers On
Pulldown Menu: DM HVAC->Layer Management->Turn Room Layers On
The room outline and room label layers will be turned on and will be visible on the drawing.