Duct Work Question
 

I have a situation concerning the heating/cooling ducts in my home that I have
a question or two about.

I have a moldy smell eminating from a register. Upon inspection of the duct
work leading to this register, I find that this register's duct branches off of
the main duct from the furnace. The main duct is rectangular in cross-section.
The branch that gives off the moldy smell is round (6 inch I think).

An examination of the joint between the round duct and the main rectangular
duct reveals that whoever did the work of making the original connection had to
have been a complete amatuer. The round duct isn't even connected, or the
connection has failed. The round duct appears to be merely inserted into a hole
cut in the top of the rectangular main duct......no tape, sealer, screws, or
any visible means of connection!!!!

I am going to fix this, but there is very little clearance to work in above the
rectangular main duct. I intend to cut a new outlet on the side of the main
duct, fit the proper fittings ( two 90 degree bends shaped into an _|`` form,
which should redirect the airflow to the approximate position I need to
reconnect the round duct), seal up the old outlet hole, demold the duct, and
hook it all back together.

1) How do I best seal up the old outlet hole? I appears to be about a 7 inch
diameter round hole on the top of the rectangular duct. I am thinking sheet
metal, metal screws, and duct sealant caulking or a gasket will do the trick.
Does anybody make a part specifically for sealing up old outlet holes as I have
described? If so, who, and how do I get one? There is very little working room
in there, so if a part is available that can easily be slipped in and secured,
it would really hep.

2 About the mold.....I have been told clorine bleach will be best for washing
out the old ducts (they are galvanised metal....so the mold will NOT be
embedded) before I reinstall them. Is this correct, or is there some other type
of product that I should use?

Thanks for any help.
Dave

Dav1936531 wrote:
...
1) How do I best seal up the old outlet hole? I appears to be about a 7
inch
diameter round hole on the top of the rectangular duct. I am thinking
sheet
metal, metal screws, and duct sealant caulking or a gasket will do the
trick. Does anybody make a part specifically for sealing up old outlet
holes as I have described?

You are on the right track. You want to use a special duct mastic to
seal the patch.

http://energyoutlet.com/res/ducts/materials.html

http://www.energystar.gov/ia/new_hom...ing1-17-01.pdf


....

Thanks for any help.
Dave

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math

I intend to cut a new outlet on the side of the main
duct, fit the proper fittings ( two 90 degree bends shaped into an _|`` form,
which should redirect the airflow

You should reconsider this plan. Any 90 degree bend in ducting rduces airflow
considerably. There are charts trhat describe these losses that some our NG
HVAC experts can comment on better than I can. A pair of 45 dgree fittings may
accomplish what you need with more effficiency. Talk to a sheet metal shop tech
about a 45 dgree outlet on a new section of ducting. Price ought to be nominal
and could make the job easier. Good luck.

Joe