Specifications

Page 4 of 40 12/03/2013
Benchmark Series Boilers
Venting and Combustion Application Guide
GF-2050
TAG-0022_0S
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
1.1 General
The AERCO Benchmark gas-fired boiler is a high efficiency, forced draft, hydronic-heating unit
with unique venting capabilities. All Benchmark venting options (which include horizontal and
vertical discharges, direct vent, and manifolded vent breeching), typically exceed the
capabilities of competing combustion equipment. These and other features enable Benchmark
boilers to provide extremely high thermal efficiencies and optimum temperature control under
widely varying conditions. It is therefore critical that the flue gas vent and combustion air
system be designed to maintain these objectives.
Benchmark’s high efficiency is achieved through air/fuel modulation and the release of energy
from the moisture condensing in the combustion products. Because condensation can occur
in the exhaust vent system, means must be provided to remove the moisture accumulation.
Each Benchmark model is fitted with a condensate removal trap, as indicated in Figures 1a –
1d, which illustrate the air inlet, vent connections and condensate removal connections for the
BMK 750 (0.75 MMBTU), BMK 1000 (1.0 MMBTU), BMK 1500 (1.5 MMBTU), BMK 2000
(2.0 MMBTU), BMK 2500 (2.5 MMBTU), BMK 3000 (3.0 MMBTU) and BMK 6000 (6.0
MMBTU) models.
The design guidelines in this bulletin provide broad latitude while meeting the objectives of
safety, longevity and optimum performance.
1.2 Materials and Approvals
The Benchmark boiler is a Category II, III, and IV appliance that requires special attention to
exhaust venting and combustion air details. The exhaust vent MUST be UL listed for use with
Category II, III, and IV appliances. The BMK 2500 and BMK 3000 can be used with
polypropylene venting materials, but NOT PVC or CPVC. The smaller size BMK 750 and BMK
1000 boilers can be used with AL29-4C, VP1738A polypropylene, PVC or CPVC vent materials,
due to their lower exhaust operating temperatures. If needed, a PVC Vent Adapter is provided in
the Spares Kit included with each BMK 750 and BMK 1000 boiler. The BMK 6000 must use UL-
listed vents made of AL29-4C stainless steel. Proper clearances to combustibles must be
maintained per UL and the vent manufacturer requirements.
The UL, National Fuel Gas Code (ANSI Z223.1/ NFPA54)
1
and CSA B149.1-10 guidelines are
often the basis for state and local codes. AERCO's recommendations follow the guidelines of
these agencies, unless more stringent codes govern the installation site. The venting and
combustion air systems must meet all applicable code requirements.
All Canada installations must comply with CSA B149.1 installation code.
1.3 Code Required Vent Terminations
The guidelines provided in this bulletin should be followed to comply with AERCO, UL, NFPA 54
(National Fuel Gas Code, ANSI Z223.1) and in Canada: CSA B149.1-10 recommendations and
regulations.
Vent terminations should be at least 4 feet below, 1 foot above or 4 feet removed horizontally
from any window, door or gravity air inlet of a building. Such terminations should extend beyond
the outside face of the wall by at least 6 inches.