Instructions / Assembly

Chapter 28 Ductwork
3
1
/4"
2
1
/4"
Wall
stack
Boot Boot
8" pipe 6" pipe
Figure 28-42. Wall stack duct is designed to fit between the
studs inside a wall. Different sizes include 2-1/4" or 3-1/4"
deep by 10", 12" or 14" wide. Standard length of a stack
section is 24".
through registers or diffusers. Both have dampers or
vanes for controlling the amount of air, but diffusers
also have adjustable vanes for controlling the direction
of discharged air. For most effective air movement,
registers and diffusers are located in the baseboard on
an outside wall, or in the floor near the baseboard.
28.14.1 Locating a Floor Diffuser
Locate the diffuser near an outside wall, but at
sufficient distance from the wall to clear draperies or
other obstructions. Draw an outline of the opening
required, then drill a hole in the center of the planned
opening. Measure from the hole to the sides of the
opening, then go into the basement or crawl space and
find the hole position from below. Measure the same
distance from the hole to be sure it will clear floor
joists or other obstructions. If not, the opening must be
shifted. See Figure 28-44.
28.14.2 Installing a Floor Diffuser
A typical one-piece diffuser fits into a 12" x 4"
rectangular opening in a register boot. Alter locating
the proper position, cut a hole in the floor just large
enough for the boot to lit snugly. The metal edges of
the boot should be level with the floor. Secure the boot
in position by nailing it to the floorboards. Insert the
diffuser into the boot and anchor it with screws at each
end. See Figure 28-45.
Floor
Wall diffuser
Floor
Figure 28-43. Placement of supply registers or diffusers is important to ensure a pleasant room temperature. A variety of
shapes and sizes are available to meet varying requirements.