Marvair AVHA 12 series Installation & Operation Manual Download Page 27

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Marvair ComPac Installation & Operation Manual

12/2017 Rev.16

For all air conditioners with electric heat, the wall sleeve

MUST

have 1” (25.4 mm) clearance around

all four sides of the opening. Attach the perimeter flange of the wall sleeve to the framed opening with

appropriately sized screws. Since electric heat can be added after the unit has been installed, Marvair

recommends that all installations have the 1” (25.4 mm) clearance around the wall sleeve.
When installing the wall sleeve, the supply opening must be on top. The supply opening is smaller than

the return air opening.

Combination Supply and Return Grille for one ton ComPac air conditioners with an economizer

A combination supply and return air grille is required for all installations of the one ton ComPac air

conditioner if equipped with an economizer. If the opening is 19” x 19” (483 mm x 483 mm), the grille,

part number 92379, must be used. If the opening is 28” x 19” (711 mm x 483 mm) the grille, part

number 80681, must be used. Attach the combination supply and return grille to the wall sleeve, using

the holes in the grille’s flange. Pilot holes must be drilled in the flange of the wall sleeve.

Wall Opening

Dimensions of Wall Sleeve

P/N of Wall Sleeve

P/N of Grille

19” x 19” (483 mm x 483 mm)

17” x 17” (432 mm x 432 mm

S/09392

92379

28” x 19” (711 mm x 483 mm)

26” x 17” (660 mm x 432 mm)

S/01784

80681

Ducting

Extensions should be cut flush with the inside wall for applications without duct work.
Applications using duct work should be designed and installed in accordance with

all

applicable safety

codes and standards. Marvair

strongly recommends referring to the current edition of the National

Fire Protection Association Standards 90A and 90B

before

designing and installing duct work. The

duct system must be engineered to insure sufficient air flow through the unit to prevent over-heating

of the heater element. This includes proper supply duct sizing, sufficient quantity of supply registers,

adequate return and filter area. Ductwork must be of correct material and must be properly insulated.

Duct work must be constructed of galvanized steel with a minimum thickness of .019 inches for the

first 3 feet (1 meter). Ductwork must be firmly attached, secured and sealed to prevent air leakage. Do

not use duct liner on inside of supply duct within 4 feet (122cm) of the unit.
Galvanized metal duct extensions should be used to simplify connections to duct work and grilles. Use

fabric boots to prevent the transmission of vibration through the duct system. The fabric must be U.L.

rated to a minimum of 197°F (92°C).

Minimum Airflow Requirements

The duct system must be engineered to assure sufficient air flow through the unit even under adverse

conditions such as dirty filters, etc. Use

Table 6

below and

Table 1

CFM at External Static Pressure

(Wet Coil)

in section 1.4.

BASIC MODEL