96 Print Reading for HVACR
Copyright Goodheart-Willcox Co., Inc.
5.3.2 Return Air Fittings
Return air fi ttings are also connected to the air handling equipment.
Depending on the confi guration of the system, the primary return trunk
can be in-line with the air handler, or it may, due to space constraints,
obstructions, or other design considerations, have to be redirected.
A number of fi ttings are used to redirect the return airstream, as
shown in Figure 5-18. These fi ttings include:
■ 5-H fi tting. A square elbow return duct fi tting.
■ 5-I fi tting. A rounded fi tting with a mitered inside corner. From a
performance and duct design standpoint, it is similar to the 5-H
return fi tting.
5-I
5-J
Return
duct
A B
C D
Square elbow
Air
handler
Supply
duct
Return
duct
Air handler
5-K
Mitered corner
Supply
duct
Air
handler
Return
duct
Radius elbow
Supply
duct
Air
handler
5-H
W W
W
Return elbows
H
H
Return air
H
Goodheart-Willcox Publisher
Figure 5-18. A—Rectangular/square return elbow at the air handler. B—Return elbow with a
mitered inside corner. C—Return radius elbow. D—Rectangular/square return elbow with
turning vanes at the air handler.