INSTALLING AIR DUCTS
A well designed and installed ducting system will allow the HRV/ERV to operate at its maximum efficiency.
Always try to keep duct runs as short and straight as possible. See Installation Diagrams for various installation options.
Outside Weatherhoods
The fixed covered hoods have a
To minimize air flow restriction, the flexible insulated duct that connects the two outside weatherhoods to the HRV/ERV should be stretched tightly and be as short as possible.
Twisting or folding the duct will severely restrict air flow. See below for the recommended connection of flexible insulated ducts to the the outside weatherhoods and the HRV/ERV.
WEATHERHOOD INSTALLATION
the ductwork.
Locating the Intake
Weatherhood
•Should be located upstream (if there are prevailing winds) from the exhaust outlet
•At least 6' (2 m) from the exhaust weatherhood
•At least 6' (2 m) away from dryer vents and furnace exhaust (medium or high efficiency furnaces)
•A minimum of at least 6' (2 m) from driveways, oil fill pipes, gas meters, or garbage containers
•At least 18" (457 mm) above the ground,
or above the depth of expected snow accumulation
•At least 3' (1 m) from the corner of the building
•Do not locate in a garage, attic or crawl space
HOOD
BIRD SCREEN
BELT OF OUTSIDE WALL
INSULATED FLEXIBLE
DUCTING
THERMAL COLLAR
1/ Thermal Collar slides over galvanized sleeve of Weatherhood.
2/ Fasten Thermal Collar to Belt.
3/ Slide the Insulated Flexible Ducting over the Weatherhood’s galvanized sleeve and fasten it to the Thermal Collar.
4/ Hood is hinged to allow for easy access for cleaning of bird screen.
Locating the Exhaust Weatherhood
•At least 6' (2 m) from the ventilation air intake
•At least 18" (457 mm) above ground or above the depth of expected snow accumulation
•At least 3' (1 m) away from the corner of the building
•Not near a gas meter, electric meter or a walkway where fog or ice could create a hazard
•Not into a garage, workshop or other unheated space When installing the weatherhood, its outside perimeter must be sealed with exterior caulking.
Installing the ducting from the weatherhoods to the HRV/ERV
The inner and outer liners of the flexible insulated duct must be clamped to the sleeve of the weatherhoods (as close to the outside as possible) and the appropriate port on the HRV/ERV. It is very important that the fresh air intake line be given special attention to make sure it is well sealed. A good bead of high quality caulking (preferably acoustical sealant) will seal the inner flexible duct to both the HRV/ERV port and the weatherhood prior to clamping.
Warmside Ducting
To maximize airflow in the ductwork system, all ducts should be kept short and have as few bends or elbows as possible.
All duct joints must be fastened with screws, rivets or duct sealant and wrapped with a quality duct tape to prevent leakage. We recommend aluminum foil duct tape.
Galvanized ducting from the HRV/ERV to the living areas in the house is recommended whenever possible, although flexible duct can be used in moderation if necessary.
To avoid possible noise transfer through the ductwork system, a short length (approximately 12 " or 300 mm) of non- metallic flexible insulated duct should be connected between the HRV/ERV and the supply/ exhaust ductwork system.
The main supply and return lines to/from the HRV/ERV must be 6 inches (150 mm) minimum. Branch lines to the individual rooms may be as small as 4 inches (100 mm), but 5 inch (125 mm) lines are preferred .
All ducts running through attics and unheated spaces must be sealed and insulated to code.
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