Trane Oxbox 14 Seer Series Installation Instructions Manual page 13

Recommended air return
duct opening size 15"×15"
* The above figures for reference purpose only.
Be sure to note supply and return openings.
Refer to Fig.3-6, 3-7 for information concerning rear and bottom supply and return air duct openings.
ROOF CURB
On applications when a roof curb is used, the unit must be positioned on the curb so the front of the
unit is tight against the curb. (See Fig. 3-6 ROOF CURB DIMENSION)
installation & owner's manual
14
Recommended air supply
duct opening size 15"×15"
Supply and return air (including duct support rails)
shown are typical for bottom duct applications.
For location of horizontal duct applications (on back
of unit), refer to unit dimension details.
Fig. 3-6 Roof Curb Dimension
NOTE
Insulation layer
Front