Indirect Gas-Fired Heat Modules
10
Install Exhaust Pipe
Slide the exhaust pipe through the CVA. Provide enough
exhaust piping to pass through the wall (or floor) and
provide the minimum clearance of 12 inches between
the exhaust pipe termination and the combustion air
intake. With all required clearances satisfied, attach the
exhaust pipe to the CVA.
Install Combustion Air Pipe
Attach a field-supplied combustion air pipe to the
concentric side of the CVA.
Be sure to provide enough combustion air piping
to pass through the wall and provide the minimum
clearance of 2 inches between the combustion air intake
and the exterior surface of the outside wall.
Be sure to maintain the minimum clearance of
12 inches between the exhaust pipe termination and the
combustion air intake.
Install CVA Assembl
y
Place the CVA assembly through the wall and verify
that all minimum clearance requirements as specified
in these instructions are met. Secure the CVA assembly
to the wall with corrosion-resistant sheet metal screws
through the mounting brackets.
Attach CVA Assembly to Unit
Attach the exhaust pipe to the unit’s combustion
exhaust. Using an additional combustion air pipe,
connect the unit’s combustion air supply intake to the
combustion air connection on the CVA.
Install Combustion Air Inlet Guard and
Exhaust Vent Terminal
Slide the combustion air inlet guard over the exhaust
pipe and fasten it to the combustion air pipe. Attach
the exhaust vent terminal to the discharge end of the
exhaust piping on the outside of the building.
Seal Opening
Seal the opening between the wall and the air intake
pipe using an appropriate method.
Concentric Venting – Vertical
Refer to the diagram below for venting on vertical
concentric systems. Maintain at least 12 inches
between the top of the combustion air inlet terminals
and the bottom of the exhaust terminal. (Dim. B).
The bottom of the combustion air intake pipe must
terminate above the snow line or at least 12 inches
above the roof, whichever is greater.
A tee with clean-out must be provided on the
combustion air and exhaust pipe to prevent debris from
entering the heat exchanger.
Vent Length
Refer to table. 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 referenced in these instructions).
Attach Mounting Brackets
Attach field-supplied corrosion-resistant mounting
brackets to the CVA using corrosion resistant sheet
metal screws.
Vent Connection Diameter
Vent terminals must be used. Construct the vent system
as shown in the drawings and refer to the table for the
correct vent connection diameters.
Vent
Length
Minimum
(feet)
Maximum
(feet)
Vertical
10
70
A = 12 inch minimum, but
should size according to
expected snow depth
B = 12 inch minimum
C = 12 inch minimum
Roof Line
Exhaust Vent
Terminal
EXHAUST
COMBUSTION AIR
Combustion Air
Inlet Terminal
Mounting
Bracket
Tee with
drip leg and
clean-out cap
Mounting
Bracket
C
C
B
A
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
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