Fantech SHR450 Manuel D'installation page 6

6
Installing ducts going to / from outside
Installing the ducting to the weatherhoods
Outside weatherhoods
The weatherhoods must have built-in "bird" screens with 1/4 inch (6.35 mm) minimum mesh to prevent birds and rodents from entering into the
ductwork. Do not use smaller mesh as it will be very susceptible to plugging up. The preferred location of the weatherhoods is:
• No less than 10 ft. (3 m) apart from each other.
• At least 18 inches (457.2 mm) above snow line or ground level.
• Supply hood must be kept away from sources of contaminants, such as automobile exhaust fumes, gas meters, garbage cans, containers,
cooling towers, tar roofs, etc.
• Avoid prevailing winds, whenever reasonably possible.
The outside perimeter of the weatherhood must be sealed to prevent leakage into the building.
The design and size of the weatherhoods or louvers chosen by the installer must allow for adequate free area. Water and snow penetration of the system
is minimized when the airflow does not exceed 1000 FPM (5.08 m/s) free area velocity.
Ducting from the weatherhoods –To and From the hrv
Galvanized sheet metal ducting with sufficient cross section with an integral single piece of insulated wrap with vapor barrier should be used to connect
the HRV to the weatherhoods. The R-value of the insulation should be adequate for condensation control. Insulated flex duct may be used in moderation,
if sized and installed properly. (Consult local codes)
All ducts should be sealed using a good bead of high quality caulking (preferably acoustical sealant) and a high quality aluminum foil tape, or other
approved duct sealant.