12 combustion air, 1 combustion from outside the building, 2 combustion air from inside the building – AERCO BMK 1000 User Manual
Page 32
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
Page 32 of 192
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
OMM-0082_0J
05/21/2014
Ph.: 800-526-0288
GF-130
While there is a positive flue pressure during operation, the combined pressure drop of vent and
combustion air systems must not exceed 140 equivalent feet or 1.9” W.C. Fittings as well as
pipe lengths must be calculated as part of the equivalent length. For a natural draft installation
the draft must not exceed - 0.25” W.C. These factors must be planned into the vent installation.
If the maximum allowable equivalent lengths of piping are exceeded, the unit will not operate
properly or reliably.
For Massachusetts installations, the following companies provide vent systems that conform to
all applicable requirements for installations within the Commonwealth of Massachusetts.
Contact information is as follows:
Selkirk Corporation - Heatfab Division
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: 1-800-772-0739
Watertown Supply
33Grove St.
Watertown, MA 02472
Phone: (617) 924-2840
M. A. Peacard
1250 Massachusetts Ave.
Boston MA 02125-1689
Phone: (617) 288-0629
Glover Sheet Meatal, Inc.
44 Riverdale Ave.
Newton, MA 02485
Phone: (617) 527-8178
2.12 COMBUSTION AIR
The AERCO Benchmark Boiler Venting and Combustion Air Guide, GF-2050 MUST be
consulted before any flue or inlet air venting is designed or installed. 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 and
warranty validation.
The more common methods of combustion air supply are outlined in the following sections. For
combustion air supply from ducting, consult the AERCO GF-2050, Gas Fired Venting and
Combustion Air Guide.
2.12.1 Combustion From Outside the Building
Air supplied from outside the building must be provided through two permanent openings. For
each unit these two openings must have a free area of not less than one square inch for each
4000 BTUs input of the equipment or 250 square inches of free area. The free area must take
into account restrictions such as louvers and bird screens. For Canada installations, refer to the
requirements specified in CSA B149.1-10, sections 8.4.1 and 8.4.3.
2.12.2 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 input or 1000 square inches of free area. The free area
must take into account any restrictions, such as louvers.