Specifications

Page 26 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
Figure 12 illustrates the preferable “transition vent section” when making the 45° connection into
a main. The main can also remain at one diameter, as long as it is sized for the total number of
units vented and the 45° branch connection is retained. Use of the recommended “transition”
assembly will reduce the overall system pressure drop.
Figure 12: Required Transition Vent Sections
The vent system should always be pitched up ¼-inch per foot of run towards the vent
termination (see Figure 13). This will enable condensate to drain back to the unit for disposal.
Low spots in the vent must be avoided. Inspect periodically to ensure correct drainage.
As shown in Figure 13, the unit at the end of the vent main must be connected via an elbow. An
end cap must not be used as it may cause vibration and flue pressure fluctuations.
As discussed previously, the static regain method should not be used for common ductwork, but
rather, the one duct size should be used for the common run.
Benchmark vents should never be interconnected to those connected to other manufacturers’
equipment.
Figure 13: Connection of Unit at End of Vent Main