MFC Series Boiler Vent and Combustion Air Guide
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GF-148-V
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3/29/2023
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required.
For
manifolded
ducted combustion
, the total section length includes both horizontal and
common vertical; individual boiler vertical connectors are included in the determination.
EXAMPLE
: For a manifolded ducted combustion that has a 10-foot common vertical, 5-foot
common horizontal after the last boiler and each boiler has an 8-foot vertical connector, the
total section linear length considered is 23 feet. Because this is less than 25 linear feet, an
attenuator is required.
Contact your local AERCO sales representative for more information on the AERCO
exhaust muffler and air inlet attenuator.
14.
Vent and Combustion Air System Design Requirements
The minimum exhaust vent and combustion air duct sizes for MFC Series boiler models are as
follows:
TABLE 3: Minimum Exhaust Vent and Combustion Air Duct Sizes
MODEL
MINIMUM DIAMETER
Combustion Air Duct Diam.
Exhaust Vent Diam.
MFC 3000
10 inch dia.
10 inch dia.
MFC 4000
12 inch dia.
12 inch dia.
MFC 5000
12 inch dia.
12 inch dia.
MFC 6000
14 inch dia.
14 inch dia.
MFC 8000
16 inch dia.
16 inch dia.
MFC 10000
16 inch dia.
16 inch dia.
A 1/4-
inch NPT combustion test hole is provided on each unit’s exhaust manifold connection. A
24-inch length of straight vent is recommended downstream of the exhaust manifold.
The vent system should always be pitched up ¼ inch per foot of run towards the vent termination
to enable condensate to drain back to the unit for disposal. Low spots in the vent must be avoided.
Periodic inspection should be performed to assure correct drainage.
MFC Series vents should not be interconnected to those of other manufacturers' equipment.
Horizontal vent and ductwork should be supported to prevent sagging, in accordance with local
code and the vent manufacturer’s requirements. Vertical vent and ductwork should be supported
to prevent excessive stress on the horizontal runs. The exhaust manifold and inlet air adapter
should never be used as weight-supporting elements. The supports should be so arranged and
the overall layout designed to assure that stresses on the vent and combustion air connections
are minimized.
The vents and combustion air ducts may be insulated in accordance with the vent manufacturer's
instructions and local codes.
15.
Condensate Removal
The exhaust vent system must be pitched back toward the MFC Series unit by a minimum of
¼-inch per foot of duct length to enable condensate to drain back to the unit for disposal. Low
spots in the vent must be avoided to prevent the condensate from collecting.
