5
C. Table - Air Distribution Duct Sizing & Design
Air Distribution Duct Sizing & Design Chart
For Ducted Applications
Return Air Cover Model
3105007.XXX
3105935.XXX
Roof Cavity Depth
2 in - 2 1/2 in Max.
Duct Cross Section Area (inside)
21 in
2
Min.
Duct Size
Depth
Width
Total Duct Length
Duct Length (short run)
1 1/2 in Min. - 2 1/2 in Max.
7 in Min. - 10 in Max.
15 ft Min. - 40 ft Max.
1/3 Min. Of Total Duct Length
Register Requirements per A/C Unit
Number Required
Free Air Area Per Register
Distance From Duct End
Distance From Elbow
4 Min. - 8 Max.
14 in
2
Min.
5 in Min. - 8 in Max.
15 in
Total System Static Air Pressure
Blower At High Speed, Filter &
Grill In Place
0.12 - 0.65 in W.C.
Note:
Duct sizes listed are inside dimensions
SPECIFICATIONS
INSTALLATION INSTRUCTIONS
A. Choosing Proper Location For Unit
This unit is specifically designed for installation on the roof
of an RV. When determining your cooling requirements, the
following should be considered:
●
Size of RV;
●
Window area (increases heat gain);
●
Amount of insulation in walls and roof;
●
Geographical location where the RV will be
used;
●
Personal comfort level required.
1. For one unit installation: The unit should be
mounted slightly forward of center (front to back)
and centered from side to side.
2. For two unit installations: Install one unit 1/3 and
one unit 2/3’s from front of RV and centered from
side to side.
It is preferred that the unit be installed on a relatively flat
and level roof section measured with the RV parked on a
level surface. See table below for maximum acceptable tilt.
Model
Number
Max
Tilt
Model
Number
Max
Tilt
57908
57912
57915
59516
59530
520300
15°
520310
520315
520316
15°
600312
600316
8°
3. After Location Has Been Selected:
a. Check for obstructions in the area where
unit will be installed. See (FIG. 1), (FIG. 2)
& (FIG. 3).
b.
Maintain structural integrity.
Otherwise damage to product and/or RV
could occur.
The roof must be designed to support 130
pounds when RV is in motion. Normally
a 200 lb. static load design will meet this
requirement.
Model
57908
57912
57915
57916
59530
29-7/8″
34-7/8″
13-1/8″
18″
Front
Dimensions Are Nominal
FIG. 1
Keep This Area Free Of Obstructions
Roof Opening
Center Line Of Unit
