AERCO BMK 3.0 LN Nat. Gas APRIL 2009 - Manual (Page 21)

INSTALLATION
2-11
The combustion air must be free of chlorine,
halogenated hydrocarbons, or other chemicals
that can become hazardous when used in gas-
fired equipment. Common sources of these
compounds are swimming pools, degreasing
compounds, plastic processing and refrigerants.
Whenever the environment contains these types
of chemicals, combustion air must be supplied
from a clean area outdoors for the protection
and longevity of the equipment.
The AERCO Benchmark 3.0 Boiler is UL listed
for 100% sealed combustion. It can also be
installed using room air, provided there is an
adequate supply. (See paragraph 2.13.3 for
more information concerning sealed combustion
air). If the sealed combustion air option is not
being used, an inlet screen will be attached at
the air inlet on the top of the unit
The more common methods of supplying
combustion air are outlined below. For more
information concerning combustion air, consult
the AERCO Benchmark Venting and
Combustion Air Guide, GF-3050.
2.13.1 Combustion Air From Outside the
Building
Air supplied from outside the building must be
provided through two permanent openings. Each
opening must have a free area of not less than
one square inch for each 4000 BTU/H boiler
input. The free area must take into account
restrictions such as louvers and bird screens.
2.13.2 Combustion Air From Inside The
Building
When combustion air is provided from within the
building, it must be supplied through two
permanent openings in an interior wall. Each
opening must have a free area of not less than
one square inch per 1000 BTU/H of total boiler
input. The free area must take into account any
restrictions such as louvers.
2.13.3 Sealed Combustion
The AERCO Benchmark 3.0 Boiler is UL listed
for 100%-sealed combustion. For sealed
combustion installations, the screen on the air
inlet duct of the unit must be removed. The inlet
air ductwork must then be attached directly to
the unit’s air inlet.
In a sealed combustion air application, the
combustion air ducting pressure losses must be
taken into account when calculating the total
maximum allowable venting run. See the
AERCO Benchmark Venting and Combustion
Air Guide, GF-3050. When using the boiler in a
sealed combustion air configuration, each unit
must have a minimum 8 inch diameter
connection at the unit.