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Marvair MAA/MGA Wall Mount AC Installation & Operation Manual
05/2023 Rev.21
APPENDIX A: Installation Instructions for Field Installed Electric Heat,
Models MAA1024A-MAA1072A
WARNING
FIRE HAZARD
Improper adjustment, alteration, service, maintenance or installation could cause serious
injury, death and/or property damage.
Installation or repairs made by unqualified persons could result in hazards to you and
others. Installation MUST conform with local codes or, in the absence of local codes, with
codes of all governmental authorities have jurisdiction.
The information contained in this manual is intended for use by a qualified service
agency that is experienced in such work, is familiar with all precautions and safety
procedures required in such work, and is equipped with the proper tools and test
instruments.
Duct Work
General Information
Note: The following instructions are for general guidance only. Due to the wide variety of installation
possibilities, specific instructions will not be given. When in doubt, follow standard and accepted installation
practices, or contact Marvair for additional assistance.
Wall Openings
Measure the dimensions of the supply and return ports on the unit.
Cut the openings in the exterior wall for the supply and return.
IMPORTANT: All units with electric heat
must have 1" (25.4 mm) clearance on all four sides of the supply outlet duct flange on the unit. The 1"
(25.4 mm) clearance must extend on all sides of the supply duct for the first 3 feet (1 meter) from the unit.
IMPORTANT: Marvair requires a minimum of 1" (25.4 mm)
from the surface of any supply ducts to
combustible material for the first 3 feet (1 meter) of the duct.
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
(122 cm) 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).
WARNING
ELECTRICAL SHOCK HAZARD
