Installation Instructions; Choosing Proper Location For Unit; C. Table - Air Distribution Duct Sizing & Design - Dometic 57908.321 Installation Instructions Manual

SPECIFICATIONS
C. Table - Air Distribution Duct Sizing & Design
Air Distribution Duct Sizing & Design Chart
Return Air Cover Model
Roof Cavity Depth
Duct Cross Section Area (inside)
Duct Size
Depth
Width
Total Duct Length
Duct Length (short run)
Register Requirements per A/C Unit
Number Required
Free Air Area Per Register
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

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 Max
Number
57908 15°
57912
57915
59516
59530
520300
3. After Location Has Been Selected:
For Ducted Applications
3105007.XXX
3105935.XXX
2 in - 2 1/2 in Max.
21 in
2
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
4 Min. - 8 Max.
14 in
2
5 in Min. - 8 in Max.
15 in
0.12 - 0.65 in W.C.
Model Max
Tilt Number Tilt
520310 15°
520315
520316
600312 8°
600316
Min.
Min.
FIG. 1
5
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.
Dimensions Are Nominal
13-1/8"
34-7/8"
18"
Center Line Of Unit
Keep This Area Free Of Obstructions
Model
57908
57912
57915
57916
59530
29-7/8"
Roof Opening
Front