Exterior Intakes

Select intake fitting:

that is appropriate for regional weather conditions and installation location

with an integrated collar at least the same diameter as the exhaust duct outlet

with an integrated pest screen with holes no less than 1/4" and no greater than 1/2"

in very cold climates that have no backflow dampers or use backflow dampers that resist freezing

Damper must open in the direction of the desired flow

Damper will close when system is off

No damper is required if the system operates continuously

Install intake to pull air from the outdoors, which does not include unconditioned spaces such as attics and crawl spaces that are ventilated with the outdoors

Install intake:

A minimum of 6" from grade;

A minimum of 10' from contaminant sources or exhaust outlets;

Above local snow or flood line;

A minimum of 18" above an asphalt based roof;

Never on a flat roof

Cut hole no larger than a 1/4" greater than the termination fitting

Weather seal and flash the exterior fitting

Mechanically fasten termination in place following manufacturer specifications

Do not inhibit damper operation if included in termination

If termination collar is larger than intake duct install a rigid metal transition

Label intake fitting: "ventilation air intake"

Seal all duct connections with UL 181B or 181B-M listed materials (e.g., mastic, tape)