AERCO BMK 2.0 LN for Mass. only - Manual (Page 22)

2-10
The Benchmark is UL listed for 100% sealed
combustion and can be ordered with a sealed
combustion option, or can be installed using
room air as long as there is an adequate supply.
(See paragraph 2.10.3 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
blower suction and the knockout at the top of the
unit will be and should remain in place.
The more common methods of supplying
combustion air are outlined below. For more
information concerning combustion air, consult
the AERCO GF-2050, Venting and Combustion
Air Guide.
2.10.1 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 boiler input.
The free area must take into account restrictions
such as louvers and bird screens.
2.10.2 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 BTUH of total boiler
input. The free area must take into account any
restrictions such as louvers.
2.10.3 SEALED COMBUSTION
The BENCHMARK boiler is UL listed for 100%-
sealed combustion and can be ordered with a
sealed combustion option or without. Units
ordered in the sealed combustion configuration
will come with an air inlet assembly installed on
the blower. The knockout at the top of the boiler
must be removed and the combustion air
ductwork must be attached to the 6" x 8" adapter
that is provided just below the knockout.
Remove and discard the screen attached to the
adapter.
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 Venting and Combustion Air Guide, GF-
2050. When using the boiler in a sealed
combustion air configuration, each unit must
have a minimum 8" diameter connection at the
unit.