Greenheck IG Installation, Operation And Maintenance Manual page 14

Installation of Two Pipe Venting –
Vertical
Refer to the diagram below for venting on vertical
concentric systems. The combustion air pipe must
terminate at least 12 inches above the roof. This
clearance may need to be increased to accommodate
for snow accumulation. The exhaust must terminate at
least 12 inches above and 12 inches horizontally from
the combustion air inlet.
Exhaust Vent
Terminal
Roof Line
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.
Furnace Size
(MBH)
75 - 175
200 - 400
Vent Length
Refer to table for minimum and maximum vent
lengths. The minimum vent length is 10 feet and the
maximum vent length is 70 feet. 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.
Vent Minimum
Length
Vertical
14
Model IG / IGX Make-Up Air
C
Combustion
Air Inlet
Terminal
B
A
D
Tee with
drip leg and
D clean-out cap
A = 12 inch minimum, but should size
according to expected snow depth
B = 24 inch minimum
C = 12 inch minimum
D = 12 inch minimum
Exhaust Combustion
(inches) (inches)
4 4
6 6
Maximum
(feet) (feet)
10 70
1. Install Exhaust Pipe
Run an exhaust pipe from the unit's combustion
exhaust through the roof to the outdoors. The exhaust
pipe must terminate at least 12 inches above the
outside surface of the roof. This clearance may need
to be increased to accommodate snow accumulation.
Attach the exhaust vent terminal to the end of the
exhaust pipe.
2. Install Combustion Air Pipe
Run a combustion air pipe from the unit's combustion
air intake through the roof to the outdoors. The
combustion air pipe must terminate at least 12 inches
horizontally and vertically from the combustion
exhaust pipe and at least 24 inches from the exterior
surface of the roof. These clearances may need to
be increased to accommodate for expected snow
accumulation. Attach the combustion air terminal to
the end of the combustion air pipe.
3. Seal Roof Penetration
Using an appropriate method, seal the roof openings
around the vent pipes.
INTAKE END
Exhaust Connection
(Model IGX)
Combustion Air Connection
(Model IGX)
Exhaust Connection
(Model IG)
DISCHARGE
END
Combustion Air Connection
(Model IG)
®