Frequently Asked Questions (Faqs) - Broan MD6TU Installation Manual

FREQUENTLY ASKED QUESTIONS (FAQS)

1. What does the Broan Automatic Make-Up Air Damper do?
The Broan Automatic Make-Up Air Damper (the "Damper") provides a pathway for fresh
air to enter a home from outdoors when a compatible exhaust device is operating. The
Damper opens when a compatible BEST, Broan Elite or Broan range hood is operating,
thereby creating a known, controlled point for fresh air to enter the home while air is
being exhausted from the building by the range hood.
By operating in this manner, the Damper provides two key benefits for the home:
• It facilitates air exchange between indoors and outdoors, by helping to allow fresh
air into the home to replace air which is exhausted out of the home.
• By allowing fresh air into the building when a compatible exhaust device is on, the
Damper helps to avoid negative pressure conditions within the home which may
interfere with the proper operation of combustion equipment within the home.
Overall, the Damper let's your BEST, Broan Elite or Broan exhaust devices do their job
more effectively and without interfering with the proper operation of other home sys-
tems.
2. Does the "Damper" provide combustion air for combustion appliances like a
water heater or a furnace?
No. The Damper helps to replace air which is exhausted by a compatible range hood.
But it does NOT help to replace air which is drawn from the indoors by a combustion
appliance like a natural gas water heater, and it should not be relied upon to perform
this function. One main reason for this restriction is that the Damper is only open when
the range hood that it's connected to is operating. So there is no assurance that the
Damper would be open when other appliances, like a water heater, are operating. Other
means must be provided to ensure adequate combustion air for these appliances.
3. How do I know if I need make-up air for my range hood?
In some cases the local building code may tell you that make-up air is necessary. For
example, some codes specify that range hoods with exhaust flows of 300 cubic feet per
minute (CFM) or higher need a mechanical system to introduce make-up air.
In other cases, make-up air for a range hood is desirable regardless of whether code
requires it. This is especially true for:
• larger range hoods (those over 300 cfm)
• homes which are well air-sealed - so outside air may not be able to easily find its
way into the home through cracks, to replace air which is exhausted out
• homes with atmospherically vented combustion appliances (i.e. a water heater or
natural draft fireplace), which are more susceptible to improper venting if depres-
surization occurs in the home.
In homes with any one of these factors make-up air is advised. And in homes with
more than one of these conditions make-up air for the range hood is strongly advised.
4. What are the benefits of providing make-up air to replace air which is exhausted
out of the home by a range hood?
Range hoods are designed to pull out pollutants like cooking odors or moisture at the
source, so they don't linger in the home. Because these fans pull air out of the house,
this air needs to be replaced with "new" air from outdoors. Normally this make-up air
enters the home through cracks and holes in the "shell" of the building. But modern
homes are air-sealed much more thoroughly so there are not as many cracks and open-
ings. Plus some exhaust fans like range hoods exhaust a lot more air than can be
replaced through normal cracks in the building shell.
By providing an intentionally designed opening for fresh air to replace air which is ex-
hausted out by the range hood, several important benefits result:
• The make-up air entering the home comes in at a known point, where it is also
filtered
• Negative pressure conditions, which could arise if air is exhausted from a home
without being replaced by new fresh air, are prevented
• Pollutants are more effectively exhausted from the home while fresh replacement
air is drawn into the home, improving ventilation
5. Does ASHRAE 62.2-2007 – "Ventilation and Acceptable Indoor Air Quality in
Low-Rise Residential Buildings" – require the use of a make-up air damper?
ASHRAE 62.2-2007 does not specifically require make-up air dampers. In a few limited
circumstances, this standard does require that net exhaust flows from a house be lim-
ited. For example, Section 6.4 of the standard limits the net exhaust flow from a home's
two largest exhaust appliances if the home has atmospherically vented or solid-fuel
burning appliances located within the pressure boundary of the house. This standard is
available at www.ashrae.org.
6. Can I use the Broan Automatic Make-Up Air Damper with other equipment in my
home?
No. The Broan Automatic Make-Up Air Damper may only be used with compatible BEST,
Broan Elite or Broan range hoods. More information on exact models of the Damper and
compatible exhaust devices can be found in the Broan Automatic Make-Up Air Damper
Application Guide.
7. What are the different ways that the Damper can be installed in my home?
The most common way to install the Damper is to connect it to a home's central duct
system. In this application, outside fresh air enters the home through the Damper and
is then routed and distributed through the home's ducts. More information on this
installation approach can be found in the Broan Automatic Make-Up Air Damper Ap-
plication Guide on our web site: www.broan.com.
8. What if my home doesn't have ducts?
Homes without ducts can still utilize the Damper to help replace air which is exhausted
from the home by the range hood. An installation illustration for this situation is in-
cluded in the Broan Automatic Make-Up Air Damper Application Guide on our web site:
www.broan.com.
9. What happens after a power outage?
The Damper system and the associated exhaust devices will not lose their settings
following a power outage. So the system will resume its normal operation following a
power outage, based on the settings it used prior to the outage.
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