On May 19, 8:09*am, Mikepier wrote:
Worst case, if you can't find a control damper somewhere in the
ductwork, replace the existing grill with a new one that has a damper
on it so you can open or close the grill.


Trace out the path from that register back to the main duct or
furnace. First, make sure that nothing has come disconnected. It's
common for taped joints to come apart and either leak badly or fall
apart completely.

As others have pointed out, it's possible you will find a flap in a
duct that controls the amount of air going to that register. If so,
if it's not fully open you can adjust it.

It's also possible that this particular run is farthest away from the
blower, is long, more turns, etc. For that, there are a couple of
possible fixes. One is the type of add-on blower that just sits on
top of the register and gets plugged into a wall outlet. It senses
when the system is on and turns itself on, pulling air out of the
register.

The other is an auxilliary blower that gets inserted into the duct
section going to that register or perhaps a couple of registers on the
same section that need more volume. The blower is powered off of the
furnace blower or with a sail type switch in the duct. I installed
one of those and it made a significant difference in airflow in the
upstairs bedrooms farthest from the furnace.