Instructions / Assembly

Heating and Cooling Essentials
Takeoff
Figure 28-20. Anemometer is used to obtain airspeed, cfm,
and temperature. (Courtesy of Sperry Instruments, Inc.)
A
B
Figure 28-21. A—Mark and cut the opening for the starting
collar on plenum. B—Insert the collar and bend tabs over.
Secure the collar with three metal screws and seal with
mastic.
Figure 28-22. Top of the takeoff should be located 6" below
the top of the plenum.
To install the takeoff, first mark off the proper size
opening. Next, pieree the metal surface using a drill or
sharp tool and cut the opening with snips. Then, insert
the takeoff into the opening, and fold the tabs down
inside. Finally, secure the takeoff with three sheet
metal screws and seal it with mastic.
28.9 Working with Round Metal Pipe-*
Standard round pipe is made of 30-gauge, galva-
nized metal. Figure 28-23. Round pipe is usually
shipped nested, with the seams open, Figure 28-23A.
Fittings are usually shipped preformed and ready to
install. Each pipe length has an easily connected snap-
lock seam. Round the pipe with your hands until the
two seam edges meet. Insert the tongue on one seam
edge into the groove on the other seam edge. Start at
one end of the pipe and work down the seam toward
the other end until the entire scam is snapped shut,
Figure 28-23B.
B
End View of
Locked Seam
Figure 28-23. Round metal pipe. A—Nested pipe lengths
with open seams. B—Self-locking seam snaps together
when compressed or squeezed with normal hand pressure.