Dometic 39726.506 Cooling Requirements, AIR Distribution System Sizing, Returnrequirements

INSTALLATION INSTRUCTIONS

2.3.1 COOLING REQUIREMENTS

When determining the cooling requirements of each vehicle, the following should be considered:

A.The size of the vehicle will determine the number of air conditioning units that are required, or the need to pre-wire for additional air conditioners depending on the geographical location of use.

B.Amount of insulation in walls, floor and roof of the vehicle.

C.Identify possible heat sources and plan accordingly:

1.Skylights - location should not be within 4 feet of the air conditioner return system.

2.Skylights - should be tinted and double pane.

3.Roof vents should be a tinted type, and quan- tity kept to minimum.

4.Increased use of slide-outs and/or glass square footage will require tinting with additional insulation in wall and ceiling cavities.

5.Calculation of heat producing appliances.

2.3.2AIR DISTRIBUTION SYSTEM SIZING

Basement systems are designed exclusively with external ductwork for the cold air discharge. There are not provi- sions for an electric heater to be installed as part of the unit. The central furnace will supply heating of the vehicle, if installed.

The condenser section must be installed so as to have direct access to the outside ambient. Removal of the heated condenser air is critical for proper operation.

The installer of this air conditioner must design the air distribution system for his particular application by following the guidelines specified within this application manual and unit installation instructions. Several specific requirements MUST BE met for the air conditioner to operate correctly:

1.Unit Total Static Pressure See Figure 2.10.

2.Duct Area Requirement. See Figure 2.10.

3.Return air to the system must be filtered to prevent dirt accumulation on the evaporator cooling surface.

4.Return air opening must be within minimums speci- fied in the system installation instructions. This figure must include the filter material selected.

5.Since duct work is located within a cavity, it is necessary that all duct work must be wrapped with a minimum R7 insulating blanket with a vapor barrier. This will help prevent heat gain within the duct and possible condensation.

CAUTION

Dometic Corporation will not be held liable for roof structural or ceiling damage if the duct work is not adequately wrapped in an insulation blanket.

CAUTION

It is the responsibility of the installer to en- sure the duct work will not collapse or bend during and after installation. Dometic Corpo- ration will not be liable for any structural dam- age due to improperly insulated, sealed or collapsed duct work.

FIG. 2.10

System	Duct	Condenser	Evap.	Static
P/N	Size	Inlet Req.	Inlet Req.	Press
39626	3x15"	648 in2	135 in2	0.40 - 1.20
39726	min.
	5x16"
	max.

2.3.3AIR DISTRIBUTION DUCT PREPARATION Depending on the distribution configuration, ensure that the air entry points have the minimum square inches required for the series of system installed. See Figure 3.4 for permissible duct layout. Duct elbows and/or restrictions must be kept to a minimum. The duct must be pre-built within the structure and sealed along its entire length. If joints or bends leak conditioned air within the cavity, condensation will form.

When the duct is installed within the structure, care must be taken to insure that the duct will not collapse or bend during or after installation of the system to the vehicle.

2.3.4 LOCATION OF DISTRIBUTION DUCT

The vehicle itself and the placement of interior components will dictate the location of the duct. One must be sure that the registers will not fall near the thermostat or the return filters. The placement must be such that the air distribution from the registers will provide the best possible movement within the living area. Calculations should be made as to the strength of the cavity, to insure structural integrity if notched for location of the duct runs.

2.3.5 RETURNREQUIREMENTS

The return air system must be considered when layout of the duct system is in process. This should be located as near to the system as possible to insure adequate return back to the evaporator coil.

2.4HI-POT REQUIREMENTS

Each system that is built by Dometic is completely checked electrically and hi-pot tested on our production line. Addi- tional hi-pot testing of the system must not be done. Disconnect the system from the power circuit prior to any vehicle high potential test operations.

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