Trane 4TCA4024A1000A Installer's Manual page 13

Table 4. Typical Rooftop Down Airflow Application with Frame
Return Air
Roof Flashing
Channel Iron Center Support
(center support required on all
frame applications).
D D u u c c t t w w o o r r k k I I n n s s t t a a l l l l a a t t i i o o n n
A A t t t t a a c c h h i i n n g g D D o o w w n n f f l l o o w w D D u u c c t t w w o o r r k k t t o o R R o o o o f f C C u u r r b b
Supply and return air flanges are provided on the roof
curb for easy duct installation. All ductwork must be
run and attached to the curb before the unit is set into
place.
A A t t t t a a c c h h i i n n g g D D o o w w n n f f l l o o w w D D u u c c t t w w o o r r k k t t o o R R o o o o f f F F r r a a m m e e
Follow these guidelines for ductwork construction:
Connections to the unit should be made with three (3)
inch canvas connectors to minimize noise and vibration
transmission.
Elbows with turning vanes or splitters are
recommended to minimize air noise and resistance.
The first elbow in the ductwork leaving the unit should
be no closer than two (2) feet from the unit, to minimize
noise and resistance.
To prevent leaking, do not attach the ductwork to the
bottom of the unit base. Refer to the bottom example in
the figure below.
88-4TCA4001-1C-EN
S S t t e e p p 4 4 — — U U n n i i t t I I n n s s t t a a l l l l a a t t i i o o n n
Angle Iron Frame
Figure 5. Attaching Down Airflow Ductwork
AIR PROOF
THIS SEAM
FIELD DUCT
UNIT DUCT
FLANGE
UNIT DUCT
FLANGE
FIELD DUCT
FIELD
DUCT
UNIT DUCT FLANGE
UNIT DUCT
FLANGE
NOT RECOMMENDED
Supply
Air
Roof
Flashing
UNIT BASE
AIR PROOF
THIS SEAM
UNIT BASE
AIR PROOF
THIS SEAM
UNIT BASE
UNIT BASE
WATERPROOF SEAM
WITH BUTYL OR
SILICONE
FIELD DUCT
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