Indirect Gas-Fired Heat Modules
9
Concentric Venting – Horizontal
Refer to the diagram below for venting on horizontal
concentric systems. Maintain at least 12 inches from
the combustion air inlet guard to the exhaust vent
terminal (Dim. B). To prevent water from running into the
combustion air pipe and to allow for easy installation
of the combustion air inlet guard, the combustion air
pipe must terminate at least 2 inches from the exterior
surface of the outside wall (Dim. A).
Vent Connection Diameter
Vent terminals must be used (one vent terminal included
with each furnace). Construct the vent system as shown
in the drawings and refer to the table for the correct vent
connection diameters.
Vent Length
Refer to table for minimum and maximum vent lengths.
The total equivalent vent length must include elbows.
The equivalent length of a
4 inch elbow is 6 feet and
the equivalent length of a
6 inch elbow is 10 feet.
Determine Venting
Location
Determine the location of the concentric venting adapter
(CVA) based on any clearances that must be maintained
(follow all codes applicable).
Attach Mounting Brackets
Attach field-supplied, corrosion-resistant, mounting
brackets to the CVA using corrosion-resistant sheet
metal screws.
Vent
Length
Minimum
(feet)
Maximum
(feet)
Horizontal
5
70
Non-Concentric Vent
Connection Diameter
Concentric Vent
Connection Diameter
Furnace Size
(MBH)
Exhaust
(inches)
Combustion Air
(inches)
Exhaust
(inches)
Combustion Air
(inches)
75-175
4
4
4
6
200-400
6
6
6
8
NOTE
Vent piping is supplied by others and not supplied by
manufacturer.
Installation of Concentric Venting
Concentric venting allows the exhaust pipe and
combustion air pipe to pass through a single hole in the
roof or wall of the building. A concentric venting adapter
(CVA) is required for concentric venting.
The concentric venting adapter is designed for indoor
installations and should never be installed on the
exterior of the building.
The exhaust pipe must terminate with the vent terminal.
For horizontal venting, the combustion air pipe must
terminate with the combustion air guard. For vertical
venting, the combustion air pipe must terminate with
the inlet terminal. Depending on what was ordered, one
of these vent terminals will be provided in the optional
venting kit along with the concentric venting adapter
(CVA).
If venting vertically through the roof, refer to the vertical
concentric venting instructions. If venting horizontally
through the wall, refer to the horizontal concentric
venting instructions.
CVA-4
4-inch Concentric
Venting Adapter
CVA-6
6-inch Concentric
Venting Adapter
Top View
Exhaust Connection
Concentric Side
Combustion Air Connection
Concentric Side
Exhaust Connection
Non-Concentric Side
Combustion Air Connection
Non-Concentric Side
CVA
A = 2 inch minimum
B = 12 inch minimum
Pitch vent pipe
downward
from furnace
1/4 inch per foot
Mounting
Bracket
Mounting
Bracket
Exhaust
Vent
Terminal
EXHAUST
COMBUSTION AIR
Exterior
Wall
B
A
Combustion
Air Inlet Guard
®
