Step 1-System in attic w/no down runs
Down runs are duct runs from attic to first floor,
through closets. If you cannot run duct from attic to first floor, you
can only cool second floor with a system in the attic. You will have to
install a second system in the basement to cool first floor (Unless
you feel like breaking your walls open for ducts). So decide if you
are able to accomplish this before continuing. If you can run ducts
through closet, there will be a down run section in this chapter.
The first thing I do when I get to a job, is go to
the attic and check to see what kind of room I got. Is the customer
using the attic for storage? Do I have room for a A/C Unit. This you will
have to determine on your own. Also, how will I get the unit in the
attic? The old trick is to make a 30" by 30" return opening in the ceiling
of the hallway, and put a return in that opening. We will do that here to
keep it simple.
In this chapter, we will be installing a air
handler with 10 feet of duct work. The air handler will be of the horizontal
type. The ductwork will be sheet metal, and we will use flexible duct to
make connections from duct to supply boxes in the ceiling . Also, I hope you
have sized your system, knowing how many tons you need. If not, you can find
that
HERE.
Once we have decided on the location of the unit, and you
have the room to accommodate the unit, and 10 feet of duct, plus room for a
return duct (approx 3 feet behind the unit), we are ready to continue. If we
do not have the room in front of unit, we will have to turn the ductwork
with a 90 degree elbow.
Step 2- Cutting and framing the return air opening and
setting the unit.
The return should be placed in a central location. Ceiling
of the hallway is always the preferred location.
In the center of the hallway ceiling, frame a
301/2" by 30 1/2" opening. This will accommodate a 30" by 30" return. This
is the largest residential return you can purchase. 30 by 30 is chosen, to
get the unit up into the attic. If you do not want a 30" by 30" return
opening, The following sizes are recommended:
•1 1/2 ton to 2 1/2 ton unit = 14" x 30". Framing opening
size 14 1/2" by 30 1/2".
•2 1/2 ton to 3 1/2 ton unit = 20" x 30." Framing opening
size 20 1/2" by 30 1/2".
•4 ton to 5 ton unit = 30" x 30". Framing opening size 30
1/2" by 30 1/2".
Step 3- Locating supply registers and cutting the holes.
to be be continued.............
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