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2. If the vent system is installed in an existing c himney make
sure clearances shown in Figure 22 are maintained. Hori-
zontal section before the termination elbow can be ex -
tended on the inlet air to provide necessary clearance.
Figure 21
Sidewall Termination with Exterior
RiserstoGetAboveSnowLevelorGrade
Level
12 ”
MIN.
8” *
MIN.
20’
MAX
*18²
²²
² Minimum for cold climates
(substainedbelow 0°
°°
° F)
25--00--04F
8”
MIN.
GRADE LEVEL
SNOW LEVEL
OR
Figure 22
Rooftop Termination
25--00--06
A
A
B
A=12² Above roof or snow accumulation level
B=8² Min., 20¢ Maximum, except in areas with extreme
cold temperatures (sustained below 0°F), the 18² Min.
Vent Termination Shielding
Under certain wind conditions some building materials may be af-
fected by flue products expelled in close proximity to unprotected
surfaces. Sealing or shielding of the exposed surfaces with a cor-
rosion resistant material (such as aluminum sheeting) may be re-
quired to prevent staining or deterioration. The protective material
should be attached and sealed (if necessary) to the building before
attaching the vent terminal.
Multi Vent Termination Clearances
When two (2) or more furnaces are vented near each other, each
furnace must be individually vented.
Two (2) vent terminations may be installed as shown in Figure 23,
Figure 24, Figure 25, Figure 26, Figure 27 and Figure 28, but
the next vent termination must be at least 36² away from first 2 ter-
minations. It is important that vent terminations be made as shown
to avoid recirculation of flue gases.
Figure 23
Concentric Vent and Combustion--Air
Roof Termination
“A”
Combustion
Air
Exhaust
12²
²²
² Min.Grade or
Snow Level
Dimension “A” is touching or 2² maximum separation.
Figure 24
Concentric Vent and Combustion--Air
Sidewall Termination
“A”
Vent
Dimension “A” is touching or 2² maximum separation.
25--22--02d
Vent
Combustion Air
1²
²²
² Maximum
(TYP.)
Exhaust
12²
²²
² Min.Grade or
Snow Level
8²
²²
² Min.
20¢
¢¢
¢ Max.
“A”
“A”
Figure 25
Sidewall Inlet Vent and Exhaust--Air
Termination
Exhaust
Inlet
Dimension “A” is touching or 2² maximum separation.
18²
²²
² Min. for
Cold Climates
(SustainedBelow 0°
°°
° F)
8²
²²
² Min.
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