Specifications

12/03/2013 Page 15 of 40
GF-2050
Benchmark Series Boilers
Venting and Combustion Application Guide
TAG-0022_0S
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
1.16 Manifolded Systems
In many instances it may be practical to connect multiple units using a manifolded vent or
exhaust configuration. However, when multiple units are connected by a manifolded air intake
or exhaust vent, the operation of a given unit can be affected by the others, if the venting or
combustion air system is not designed properly. Properly designed common vent and air supply
systems can be installed that will prevent "operational interaction" between units.
Do not use static regain method on common ductwork, but rather, use one duct size for
the common run (See Figure 13).
Contact your AERCO sales representative or AERCO International for design assistance
and approval when designing manifolded exhaust vent systems.
1.17 Elbow Quantity and Separation
The quantity and angle of elbows and the distances between them can influence the system’s
exhaust and combustion air pressures, as well as its acoustical behavior. Designers should
consider minimizing the quantity of elbows in the design and the use of angles less than 90°,
whenever possible. Five or fewer elbows are recommended for individual venting/connections;
five or fewer are recommended for common sections. The minimum distance required
between two elbows is five feet.
1.18 Exhaust Muffler And Air Inlet Attenuator Guidelines
The Benchmark requires an exhaust muffler when it is installed in a noise-sensitive application
and when the exhaust vent ducting is relatively short in length. The following criteria should be
used to determine when to include a field-installed muffler in a Benchmark installation:
• The exhaust is sidewall vented and the vent is terminated in close proximity to
residences, offices, hotel/hospital rooms, classrooms etc.
OR
• The total vertical section of exhaust vent is less than 25 linear feet in length, and the
vent terminates in close proximity to residences, offices, hotel/hospital rooms,
classrooms etc.
For manifolded exhaust systems, the total vertical section includes only the common vertical;
individual boiler vertical connectors are not included in the determination. For example, if the
installation has a 20-foot common vertical, and each boiler has a 10-foot vertical connector, the
total vertical section is only 20 feet. Because this length is less than 25 linear feet, a muffler is
required.
For manifolded ducted combustion, the total vertical section includes only the common vertical;
individual boiler vertical connectors are not included in the determination.
For example, if a manifolded ducted combustion has 20-foot common vertical, and each boiler
has a 10-foot vertical connector, the total vertical section is only 20 feet. Because this is less
than 25 linear feet, an attenuator is required.
An adapter kit is available for the BMK 750 and BMK 1000 units allowing the use of a muffler
with PVC piping. When using PVC piping, it is necessary to install the muffler at the end of the
vent piping, as shown in Figure 7. Part numbers for 6” and 8” kits are also shown in Figure 7.