Installing Ducts To / From Inside; Supply & Exhaust Air Grilles Location - Fantech VHR 704 Manuel D'installation

10

Installing ducts to / from inside

• Building Codes and
Combustion Appliance
Installation Codes do not
allow location of return air
grilles or any opening such
as a "breathing tee" in an
enclosed room with spillage
susceptible combustion
appliances.
• The fresh air inlet from
the HRV needs to respect
a minimum distance
from the furnace return
drop to ensure proper air
mixing and temperature
at the furnace core. See
furnace manufacturer for
appropriate specifications.
Exhaust air ducting
The stale air exhaust system is used to draw air from the points in the house where the worst air quality problems occur. Due to its lower capacity,
the VHR 704 is designed to vent from a single source point only and to the bathroom that is closest to the unit or directly out of the furnace return.
Additional source points may be drained from if designed properly or installed on a separate Fantech fan bath kit to ventilate additional areas. Fantech
bath kits are listed below and are ideal for both new construction and retro fit.
fantech
To maximize airflow in the ductwork system, all ducts should be kept short and have as few bends or elbows as
possible. Forty-five degree are preferred to 90º elbows. Use "Y" tees instead of 90º elbows whenever possible.
All duct joints must be fastened with screws or duct sealant and wrapped with a quality tape to prevent leakage.
Aluminum foil duct tape is recommended. Galvanized ducting from the HRV to the living areas in the house is
recommended whenever possible, although flexible duct can be used in moderation when necessary.
The VHR 704 should be installed with a 4" (100mm) duct system that has less than 80 ft (25m) of
equivalent duct length on the supply and on the exhaust side. If longer runs are required, increasing
the duct diameter or following the instructions below might help.
It is the responsibility of the installer to ensure all ductwork is sized and installed as designed to
ensure the system will perform as intended. All air movement devices have a performance curve. The
amount of air (CFM) that an HRV will deliver is directly related to the total external static pressure
(E.S.P.) of the system. Static pressure is a measure of resistance imposed on the blower by length of duct work/number
of fittings used in duct work, duct heater etc.
Supply air grilles location
In homes without a forced air furnace, fresh air should be supplied to all habitable rooms including, bedrooms and
living areas. It should be supplied from high wall or ceiling locations. Grilles that diffuse the air comfortably such as
Fantech Contour Grilles are recommended. To avoid possible noise transfer through the ductwork system, a short
length (approximately 12", 300 mm) of nonmetallic flexible insulated duct should be connected between the HRV and
the supply/exhaust ductwork system.
If the floor is the only option available, then special care should be taken in locating grilles. Areas such as under
baseboard heaters will help to temper the air. Also optional inline duct heaters are available for mounting in the
supply duct work to add heat if required. In homes with a forced air furnace, you may want to connect the HRV to
the furnace ductwork (see information below).