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7Aiii. Intake Air Connection and Duct Installation
ASHRAE recommends that the fresh air intake be located at least 10 feet from any source of pollutants
such as auto exhaust, dryer exhaust, exhaust from any fuel-burning appliance, etc. Avoid installation
near odor sources such as garbage bins or barbecue grills. A minimum of 3 foot above ground is
recommended to avoid ingress of leaf litter, grass clippings, etc. Do not use a crawl space, basement
or attic as a source of intake air. Always be sure to comply with local building code requirements
regarding fresh air inlets.
Ductwork Specifi cation
• All fl exible ducts must meet UL safety standards for Class I air ducts and connectors.
• All ducting must be installed according to HVAC codes and standards.
• All duct connections should be sealed with UL181 foil tape or mastic to prevent leakage.
• Insulated duct of at least R-4 insulating value with a continuous vapor barrier must be used for the
intake duct. The vapor barrier must be sealed at both ends.
• Exterior intake should be installed above snow line or a minimum of 18" above ground level,
whichever is greater.
• Exterior intake hood must be weather resistant and must have a screen (1/4" openings) to
prevent debris, animals and insects from entering ductwork.
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P/N 780100700 07/18 Rev F
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