I have a forced air heating/AC in my 2 story home. The main ductwork is in the basement, and easily accessible; there is a main rectangular trunk line that feeds the various rooms using 4 to 7" flexible duct with manual dampers coming off the main line. One of the 4" lines coming off the main trunk is called a "bleeder" on the house plans. From the drawing, it appears to end under the master bathroom floor, in the garage ceiling. I can't access that area as it is covered in drywall. Also, there should be insulation inside the bathroom floor/garage ceiling.
My question is, what is the purpose of a duct that's called a "bleeder", and appears to just end without a vent between a garage ceiling/bathroom floor?
I would expect the insulation would block any airflow, but I don't know for sure what's in there. Should this damper be left open, or closed? I am having problems getting enough air flow to our master bedroom, which is above the garage, I'm trying to figure out if this "bleeder" duct is part of the problem.