Dometic 457915.30X Installation Instructions Manual page 6

• Duct size
• Duct layout
• Register size
• Register location
• Thermostat location
• Indoor Temperature Sensor Location
These items must be determined in conjunction
with the Air Distribution Duct System Sizing and
Design Requirements listed in the chart below.
Important:
Alternate configurations and methods may
be used which still allow the unit to operate properly;
however, these alternate configurations and methods
must be approved by Dometic, LLC in writing. The fol-
lowing instructions are based upon the use of Return
Air Grill Kits 3105007.XXX & 3105935.XXX
Air Distribution Duct Sizing & Design Chart For Ducted Applications
Roof Cavity Depth
Duct Cross Sectional Area
Duct Size
Depth
Width
Total Duct Length
Duct Length (short run)
Register Requirements
Number Required Per Run
Register Free Air Area
Distance From Duct End
Distance From Elbow
Total System Static Air Pressure
Blower at High Speed,
Filter & Grill In Place
Note: Duct sizes listed are inside dimensions.
FIG. 5
Duct Size And Requirements For 3105007.XXX And 3105935.XXX Return Air Grill
Register Required
Short Duct Run Minimum
1/3 Total Duct Length
Ducts Min.
Depth 1-1/2"
Width 7.0"
Total Length 15.0'
Register Required
Note: Duct Size is Inside Dimensions
Return Air Grill Kit
3105007.XXX
3105935.XXX
2.0 In. Min. - 5-1/2 In. Max.
21.0 Sq. In. Min.
1-1/2 In. Min. - 2-1/2 In. Max.
7.0 In. Min. - 10.0 In. Max.
15.0 Ft. Min. - 40.0 Ft. Max.
1/3 Total Duct Length
4 Min.
14.0 Sq. In.
5.0 In. Min. - 8.0 In. Max.
15.0 In.
0.55 - 0.90 In. W.C. 4579 Series
0.40 - 1.10 In. W.C. 4595 Series
Total Outlet Air Area
Minimum 21.0 Sq. In.
Max.
2-1/2"
10.0"
40.0'
Roof
Rafters
14-1/4" x 14-1/4" (± 1/8")
Roof Opening
6
Register Required
Registers
8 Min. - 12 Max.
(Per Unit)
14 Sq. In. Free
Area Per Register
Register Required