Using Exterior Risers
1.Install elbows and pipe to form riser as shown in Fig. 23
2.Secure vent pipe to wall with galvanized strap or other rust resistant material to restrain pipe from moving.
3.Insulate pipe with Armaflex or equivalent moisture resistant closed cell foam insulation or Fiberglass insulation if boxed in and sealed against moisture.
Vertical Termination
1. Fig. 25 shows the proper installation and clearances for |
vertical vent termination. The vertical roof termination |
should be sealed with a plumbing roof boot or equivalent |
flashing. The inlet of the intake pipe and end of the exhaust |
OVERHANG
EXHAUST 12″ (304.8mm) MIN.
90°
INLET
12″ (304.8mm) MIN. Ground
Level OR Snow Level
25- 23- 73
vent must be terminated no less than 12″ (307.8mm) above |
the roof or snow accumulation level, and 12″ (307.8mm) |
away from a vertical wall or other protrusion. |
2. If the vent system is installed in an existing chimney make |
sure clearances shown in Fig. 25 are maintained. Horizontal |
section before the termination elbow can be extended on the |
inlet air to provide necessary clearance. |
Vent Termination Shielding
Under certain wind conditions some building materials may be affected by flue products expelled in close proximity to unprotected surfaces. Sealing or shielding of the exposed surfaces with a
FRONT VIEW
Same Joist
Space
SIDE VIEW
12″ (304.8mm) MIN.
A07699
58HDV
corrosion resistant material (such as aluminum sheeting) may be required 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 Fig. 26, 27, 28, 29, and 30 but the next vent termination must be at least 36″ (914.4mm) away from first two terminations. It is important that vent terminations be made as shown to avoid recirculation of flue gases.
Fig. 24 - Recommended Alternate Installation
for Sustained Cold Weather
(0_F (-17_C) & below for 24 or more consecutive hours)
B
A
8” (203.2mm)* MIN. 20’ (6.1m) MAX
*18″ (457.2mm) Minimum for cold climates [sustained 0_F (- 17_C) and below for 24 or more consecutive hours]
8” (203.2mm) MIN.
12 ” (304.8mm)
MIN.
GRADE LEVEL |
|
OR |
|
SNOW LEVEL |
A07716
A
25--00--06
A = 12″ (304.8mm) Above roof or snow accumulation level B = 8″ (203.2mm) Min., 20′ (6.1m) Maximum, except in areas with extreme cold temperatures [sustained
Min.
A07717
Fig. 25 - Rooftop Termination
Fig. 23 - Sidewall Termination with Exterior Risers to Get
Above Snow Level or Grade Level
29
