Attached picture (1st pic) is ceiling of 2nd floor condominium laundry room, there is HVAC and water heater also in the room. Due to recent water damage ceiling was removed. I have question about flexible ducts shown by yellow and red dots in the picture.
1st picture is laundry room, 2nd picture is adjacent bathroom.
In laundry room, One end of the duct with yellow dotted line is connected with solid vent which goes down the wall on left side and opens in vent near the floor (not in the picture)
One end of the duct with red dotted line opens in ceiling vent as you can see in the picture.
Blue arrow shows HVAC plenum, you can tell that these ducts are not connected to it.
Both of these ducts go toward the adjacent bathroom ceiling (2nd picture).
In the bathroom ceiling, both of these flex ducts are connected to solid metal ducts which goes further to the right towards my walk in closet, which is end of my unit (Walk in closet has outside wall of building).
Both duct opens outside the building like shown in 3rd picture.
I just don't understand purpose of these vents. When my HVAC turns on, I don't feel any air coming out of vent in the wall (for yellow duct) and vent in the ceiling (for red duct).
Can someone tell me what are these ducts for ?