AERCO BMK 3.0 LN Dual-Fuel Series Gas Fired Low NOx Boiler System - Manual (Page 22)

INSTALLATION
2-12
2.13 COMBUSTION AIR
The AERCO Benchmark Venting and
Combustion Air Guide, GF-2050 MUST be
consulted before any flue or combustion supply
air venting is designed or implemented.
Combustion air supply is a direct requirement of
ANSI 223.1, NFPA-54, CSA B149.1 and local
codes. These codes should be consulted before
a permanent design is determined.
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 Dual-Fuel 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-2050.
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 re-
strictions such as louvers and bird screens. For
Canada installations, refer to the requirements
specified in CSA B149.1.10, 8.4.1 and 8.4.3.
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 Dual-Fuel 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-2050. When using the boiler in a
sealed combustion air configuration, each unit
must have a minimum 8 inch diameter
connection at the unit.
2.13.4 Temporary Combustion Air
Filtering During Construction
When the AERCO Benchmark 3.0 Dual-Fuel
Boiler is used to provide heat temporarily during
ongoing building construction, accumulated
drywall dust, sawdust and similar particles can
accumulate in the unit’s combustion air intake
filter and block combustion air flow. In these
situations, AERCO recommends that a
disposable air intake filter be installed,
temporarily, above the boiler combustion air
inlet.
AERCO recommends that the temporary air filter
be cut from a McMaster-Carr part no. 2122K315
Polyester Air Filter Roll Tackfield, ½” thick, 16”
wide, or equivalent. Cover the Benchmark 3.0
air inlet with the blue side of the filter material
facing outward to hold the dust on the outside
surface. Maximize the surface area of the filter
covering the 8" diameter opening by creating a
dome out of the filter material.
Cover the flared duct opening with the blue side
facing outward. During construction check the
filter for dust accumulation and replace it when
the accumulation becomes noticeable.