MODELS MD6TR • MD8TR
Page 2
OUTSIDE AIR INTAKE LOCATION
Proper design and location of the outside air intake location is critical in
ensuring that the Damper can safely and reliably provide an opening for
fresh air to enter the home. The following requirements for the location
of the outside air intake must be met:
• Outside air intake is located a minimum of 10’ from combustion ap-
pliance vents, chimneys, plumbing stacks, and bathroom or kitchen
exhaust vents. If local codes have more stringent separation re-
quirements, they shall apply.
TYPICAL INSTALLATIONS
Installations will vary according to the location in the home where the unit is installed and which model Damper is used. Use the following
illustrations and notes as guidance for your own installation. Always comply with local code requirements and in any instance where a detail
shown below conflicts with local code, the local code provision shall apply.
Damper connected to return side of central duct system.
• Outside air intake is placed high enough above grade to prevent
blockage from snow or other debris such as leaves, and at a mini-
mum of 1’ above grade.
• Make-up air damper should not draw air from crawlspaces, ga-
rages, attics, adjacent dwelling units, or any enclosed part of the
building. The Damper should be installed to draw air directly from
outdoors.
OUTSIDE AIR INTAKE OPENING PROTECTION
Because the Damper, together with the end cap and outside air duct
which are installed with it, will allow outdoor air into the indoor environ-
ment, it is important to meet the following requirements:
• Model 641FA (6”) and 643FA (8”) fresh air inlet wall caps include
protective bird screens to keep out animals and outside debris.
Clean screens often and do not remove.
• If a protective bird screen other than the screen provided is used, it
must cover the entire opening of the outside air duct. This screen
must also have openings of at least ¼” but no larger than ½”.
• The outdoor air intake opening should meet local code provisions
for the protection of openings in exterior walls, including steps to
prevent moisture intrusion around the opening.
Note that the screen over the outside air opening is not a filter. It is
intended to prevent the intake of leaves, animals, or debris into the out-
side air duct. A downstream filter is necessary to remove pollen, dust,
and other airborne particles. Potential filter locations are shown below
in the Typical Installations section.
MINIMUM RETURN AIR TEMPERATURE REQUIREMENTS
HVAC equipment manufacturers may have minimum requirements for
the air temperature in the return air plenum. Introducing outdoor air to
the return side of the central duct system may impact this temperature.
The installer should adjust both the size of the outside air duct and the
location of its connection to the return side of the central duct system in
a manner so that minimum air temperature requirements are satisfied
under design conditions.
AIR HANDLER UNIT
COOLING APPARATUS
AIR DISTRIBUTION FAN
HEATING APPARATUS
THERMOSTAT
CENTRAL SYSTEM SUPPLY AIR
REGISTER BOX ADAPTED
WITH SLIDE-IN FILTER (optional)
AUTO. MAKE-UP AIR DAMPER
FIELD MEASUREMENT OF OUTSIDE
AIR DUCT PRESSURE. (See “Install The
Damper” section on page 3 for damper
balancing instructions.)
FRESH AIR INLET WALL CAP
WITH BIRD SCREEN
INSULATED OUTSIDE
AIR DUCT (slope toward wall cap)
EXTERIOR WALL
VENTILATION AIR INTAKE
(locate away from pollutant sources)
CENTRAL SYSTEM RETURN AIR
FURNACE FILTER
PLAN THE INSTALLATION
Planning the installation first requires selecting the most appropriate
installation approach. The chart below offers suggestions for the most
effective installation approach by considering a few important factors.
Further details on the two main types of installations are provided below.
Yes
•
House has central duct work?
Yes
•
Return-air side of duct work is
accessible -either the return-air trunk
or return- air plenum?
Damper connected to
return side of central
duct system
No
No
Damper ducted directly
to a ceiling, floor, or wall
register
