annur wrote:
My tenant recently complained about one of the bedroom upstairs being
too hot. When I checked the vents in the floor (there are 2 vents) in
this bedroom, one of them has more air blowing than the other one. I
also checked all the rooms, and there is more air blowing on all of
them. Except this one vent in the bedroom does not have enough air
blowing. For this vent that has a problem, I opened the vent and
checked if there is anything stuck which I did not see and everything
seems to ok as far as I know. Is there something I can do to fix this
problem?


Close the vents that do work partway, so more of the air will go to the slow
one. Look for controls on the vents closer to the A/C, such as in the basement
ceiling - there could be one for the slow vent partially closed.

They do make booster fans that can be inserted into ducts.