Ducts and Duct Systems:Mobile Home Duct Systems

Mobile Home Duct Systems

Duct kits for adding central air-conditioning to forced warm-air heating systems are available from some manufacturers for installation in mobile homes, and particularly for installation in the double-wide combination mobile homes.

A typical air-conditioning duct kit installation is illustrated in Figure 7-26. The air conditioner is located outdoors and the cool air is supplied to the mobile home by a round (12-inch diameter) flexible duct that leads from the air-conditioning unit to the long metal heating ducts located in the center of the structure. A transition

tee with a short length of round, nonflexible metal duct connects the flexible duct leading from the air conditioner to the metal heating duct running the length of the mobile home through a supply air opening (not to be confused with the warm-air registers on the top of the heat supply duct and which are a part of the existing heating system).

A return air grille is located in the floor near the outside wall closest to the air conditioner. As shown in Figure 7-27, the return grille is located over an enclosure that contains a filter for cleaning the air returning to the air conditioner.

The flexible cool-air supply duct is connected by cutting a 16-inch by 16-inch square opening in the flooring directly beneath the main heat supply duct at the chosen location. A smaller 121⁄2-inch-wide hole is then cut through the bottom of the heating duct. An adapter plate with a round opening is placed over the opening in the heating duct and secured in place with screws. Tape is then run around the outer edge of the adapter plate to seal it against air leaks (see Figure 7-28). Supply air outlets closest to the air conditioner use an adapter plate with a 12-inch opening. Those farthest away use an adapter plate with a 10-inch opening.

Before locating the best position for the air conditioner and routing the flexible duct, the positions of the supply air outlets and the return air grille should be determined. When doing this, the following recommendations are offered:

• Never locate the supply air opening closer than 4 feet from the furnace.

• Never locate the supply air opening directly under a supply register.

• Connect the flexible cool-air supply duct to the main heating duct as close to the center of the mobile home as possible.

• Locate the return air grille in a room or area open to the rest of the mobile home so that proper air circulation may be maintained.

• Provide adequate accessibility to the return air enclosure for cleaning or replacing the filter.