Best MD10TU User Manual
Broan® Automatic Make-Up Air Damper
Application Guide
Residential Use Only
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INSTALLER: Leave this guide with the consumer.
Broan–NuTone LLC Hartford, Wisconsin www.broan.com 800-558-1711
Broan Automatic Make-Up Air Damper Product Guide – 04-17-13 1
99044565B
About the Application Guide
Congratulations on your purchase of the Broan Automatic Make-Up Air Damper! This product,
called the “Damper” throughout this guide, is designed to keep your home well ventilated and
comfortable for years to come. The Damper works automatically once it’s properly installed with
a compatible Broan®, NuTone®, or BEST® exhaust device, so you won’t have to give your
home’s exhaust systems a moment’s thought.
Please read this Guide thoroughly, noting the specific applications for which the Broan
Automatic Make-Up Air Damper is intended, as well as the different installation approaches.
Installers – note that a separate set of Installation Instructions for the Damper is available from
Broan. The Application Guide does not contain specific installation instructions.
Important Information about the Application Guide
Please take note that this guide uses the following symbols to emphasize particular information:
About the Broan Automatic Make-Up Air Damper Unit
TO REDUCE THE RISK OF FIRE, ELECTRIC SHOCK, OR INJURY TO PERSON( S)
OBSERVE THE FOLLOWING:
1. This Damper is intended for residential installation only.
2. Installation work and electrical wiring must be done by a qualified person(s) in
accordance with all applicable codes and standards, including fire-rated construction
codes and standards.
3. This Damper is not designed to provide combustion air for fuel-burning appliances.
4. Sufficient air is needed for proper combustion and exhausting of gases through the flue
(chimney) of fuel burning equipment to prevent backdrafting. Follow the heating
equipment manufacturer’s guideline and safety standards such as those published by
the National Fire Protection Association (NFPA), and the International Fuel Gas Code
(IFGC), and the local code authorities.
Broan Automatic Make-Up Air Damper Product Guide – 04-17-13 2
5. Do not connect the Damper directly to a combustion appliance of any type.
6. Before servicing or cleaning Damper, switch power off at service panel and lock the
service disconnecting means to prevent power from being switched on accidentally.
When the service disconnecting means cannot be locked, securely fasten a prominent
warning device, such as a tag, to the service panel.
7. When performing installation, servicing or cleaning the Damper, it is recommended to
wear safety glasses and gloves.
8. The Damper is approved for use with compatible Broan, BEST, and NuTone products.
Unless specifically noted, Broan does not warrant proper operation of the Damper if
used in conjunction with other brands of exhaust devices.
9. Ensure that the intake area for the outdoor air duct is free of potential obstructions and
maintained regularly.
10. When cutting or drilling into wall or ceiling, do not damage electrical wiring or other
hidden utilities.
11. When notching or drilling into framing including floor supports, rim joists, and wall studs,
comply with code and manufacturer limitations on allowable modifications to these
structural members.
12. This Damper is intended to be installed within the home in a location protected from
moisture.
13. This unit must be in an accessible location which allows for inspection of the Damper.
14. Use this Damper only in the manner intended by the manufacturer. If you have
questions, contact the manufacturer at the address or telephone number listed in this
document.
15. When federal, provincial, state, or local legislation or building codes comprise more
restrictive installation and/or certification requirements, the aforementioned requirements
prevail on those of this document, and the installer agrees to conform to these at his own
expense.
CAUTION
1. Damper is for general household ventilation only. Do not use for ventilation near
hazardous materials or explosives.
2. Damper shall not be installed to introduce air from crawlspaces, garages, attics, adjacent
dwelling units, or other locations within the building shell. Damper shall be installed to
introduce air directly from outdoors.
3. Do not run the outdoor air duct directly above or closer than 2 feet to any furnace or its
supply plenum, boiler, or other heat producing appliance.
4. Any ductwork used in conjunction with the Damper must be installed in compliance with
all local and national codes that are applicable.
5. Do not operate the Damper for fresh outdoor air introduction until all system filters,
including the central duct system filter, have been installed per the system design.
Broan Automatic Make-Up Air Damper Product Guide – 04-17-13 3
6. Please read the Damper specification label on the product for further information and
requirements.
7. The Damper’s outdoor air intake, ducting, and any filters should be inspected and
maintained on a regular basis.
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TableofContents
1. Definitions & Key Terms ........................................................................................... 6
2. What is Make-Up Air? .............................................................................................. 7
3. Broan Automatic Make-Up Air Damper – Product Function ..................................... 8
4. Different Models of the Broan Automatic Make-Up Air Damper ............................... 8
5. When to Use the Broan Automatic Make-Up Air Damper ........................................ 9
6. Common Applic ations .............................................................................................. 9
6.1 Applications with the LinkLogic™ Model (SMD* model) ................................... 10
6.2 Applications with the Direct-Wired Model (MD*T model) .................................. 10
6.3 Applications with the Universal Model (MD*TU model) .................................... 11
6.4 Applications with the Slave Model (MD*S model) ............................................ 11
7. Planning the Installation ......................................................................................... 12
7.1 Sizing the Damper & the Duct .......................................................................... 12
7.1.1 Using the On-line Make-Up Air Specifier ................................................... 13
7.1.2 Simplified Sizing in the Absence of Building Codes ................................... 14
7.1.3 Testing ....................................................................................................... 14
7.2 Outdoor Air Intake Location.............................................................................. 14
7.3 Outdoor Air Intake Opening Protection ............................................................ 15
7.4 Climatic Considerations for Outdoor Air (OA) Ducts Connected to Central Duct
Systems ..................................................................................................................... 15
8. Typical Installations ................................................................................................ 16
8.1 Damper Connected to Return Side of Central Duct System ............................ 16
8.2 Damper and OA Duct Connected Directly to a Ceiling, Floor, or Wall Register 16
9. Installation .............................................................................................................. 17
10. System Operation ................................................................................................ 17
11. Maintenance ........................................................................................................ 17
12. Frequently Asked Questions (FAQs) ................................................................... 18
Broan Automatic Make-Up Air Damper Product Guide – 04-17-13 5
1. Definitions & Key Terms
Within the scope of this document, several important terms are used. To give product installers
and users a clear understanding, several key terms are defined below.
Available static pressure: for the purpose of this guide, available static pressure represents the
amount of suction that is available to draw in outdoor make-up air when the central air handler is
running. Manual D, the industry standard for sizing residential duct systems, notes that an
available static pressure between -0.2 and -0.35 in w.g. is typical at the return plenum. When
estimating the flow through a make-up air damper that is connected to a return trunk, provide
the available static pressure at the operating speed of the blower that will be used when the
make-up air damper is engaged.
Natural draft vented appliances: a category of combustion appliances, including some water
heaters, wood burning stoves, and fireplaces, which rely upon the buoyancy of the hot
combustion exhaust gas to force it upward through a flue pipe and out of the house. Such
appliances do not use a fan to assist in exhausting combustion gasses outdoors.
Combustion air: The air provided to fuel-burning equipment including air for fuel combustion,
draft hood dilution and ventilation of the equipment enclosure.
1
Depressurization: a condition of lower pressure in one zone with respect to another. For
example, a kitchen with a very large range hood flow rate (~ 1000 cfm) may be depressurized
with respect to outdoors when the range hood is on. This is due to the fact that the range hood
is pulling air out of the kitchen space at a rate greater than the rate at which fresh outdoor air
replaces the exhaust air. Pressure levels in homes are typically measured in units called
Pascals (1 Pa = 0.004 in w.g.), and are measured “with respect to” another zone such as
outdoors or a different part of the home.
Design depressurization limit: the designer-selected maximum depressurization of the home
with respect to the outdoors, selected by the designer and assuming indoor spaces freely
communicate with each other. Recommendations from the Building Performance Institute for
maximum acceptable depressurization in a home depend on the types of combustion
appliances that are installed indoors, as follows. Lower values are more conservative.
• Orphan natural draft water heater (including outside chimneys): 2 Pa
• Natural draft boiler or furnace commonly vented with water heater: 3 Pa
• Natural draft boiler or furnace with vent damper commonly vented with water heater;
Individually vented natural draft boiler, furnace, or domestic water heater; or
Mechanically assisted draft boiler or furnace commonly vented with water heater: 5 Pa
• Mechanically assisted draft boiler or furnace alone, or fan assisted domestic hot water alone:
15 Pa
• Chimney-top draft inducer (Exhaust-type or equivalent);
High static pressure flame retention head oil burner; or
Direct-vented appliances/Sealed combustion appliances: 50 Pa
Design exhaust rate: the flow rate that must be offset by make-up air. Depending on friction
losses and fittings along the length of the exhaust duct, the design exhaust rate may be less
than the exhaust appliance’s nominal rated flow.
1
Sourced or adapted from the 2012 International Residential Code.
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