Details of Intake and Exhaust Piping Terminations for Direct Vent Installations
NOTE − In Direct Vent installations, combustion air is tak- en from outdoors and flue gases are discharged to out- doors.
NOTE − Flue gas may be slightly acidic and may adversely affect some building materials. If any vent termination is used and the flue gasses may impinge on the building ma- terial, a corrosion−resistant shield (minimum 24 inches square) should be used to protect the wall surface. If the optional tee is used, the protective shield is recommended. The shield should be constructed using wood, plastic, sheet metal or other suitable material. All seams, joints, cracks, etc. in the affected area should be sealed using an appropriate sealant. See figure 21.
Intake and exhaust pipes may be routed either horizontally through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the roof is preferred. Figures 19 through 28 show typical termina- tions.
1 − Exhaust and intake exits must be in same pressure zone. Do not exit one through the roof and one on the side. Also, do not exit the intake on one side and the exhaust on another side of the house or structure.
2 − Intake and exhaust pipes should be placed as close together as possible at termination end (refer to il- lustrations). Maximum separation is 3" (76mm) on roof terminations and 6" (152mm) on side wall termina- tions.
3 − On roof terminations, the intake piping should termi- nate straight down using two 90° elbows (See figure 19).
4 − Exhaust piping must terminate straight out or up as shown. A reducer may be required on the exhaust pip- ing at the point where it exits the structure to improve the velocity of exhaust away from the intake piping. See table 9.
NOTE − Care must be taken to avoid recirculation of exhaust back into intake pipe.
FIELD−SUPPLIED WALL TERMINATION OR (15F74) WALL RING TERMINATION KIT
NOTE − FIELD−PROVIDED |
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REDUCER MAY BE |
| 1/2" (13mm) ARMAFLEX | |
REQUIRED TO ADAPT |
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| INSULATION IN | ||
LARGER VENT PIPE SIZE |
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| UNCONDITIONED SPACE | ||
TO TERMINATION. |
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| SIZE TERMINATION |
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| PER TABLE 9 |
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| D |
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| B |
| C |
| STRAIGHT |
| A | APPPLICATION | |
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| 1/2" (13mm) ARMAFLEX INSULATION | ||
| IN UNCONDITIONED SPACE | ||
| E |
| D |
* WALL |
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SUPPORT |
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| B |
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| A |
| C |
| EXTENDED |
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| APPLICATION |
See venting table 7 for maximum venting lengths with this arrangement.
*Use wall support every 24" (610 mm). Use two wall supports if extension is greater than 24" (610 mm) but less than 48" (1219 mm). NOTE − One wall support must be 6" (152 mm) from top of each pipe (intake and exhaust).
2" (51mm) | 3" (76mm) |
Vent Pipe | Vent Pipe |
Inches(mm)
3"(76mm) MAX.
SIZE TERMINATION PIPE PER TABLE 9.
UNCONDITIONED
A−Minimum clearance |
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above grade or average | 12" (508MM) | 12" (508MM) |
snow accumulation |
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B−Maximum horizontal |
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8" (203mm) MIN
12" (305mm) ABOVE |
AVERAGE SNOW |
ACCUMULATION |
ATTIC SPACE
1/2" (13mm) FOAM
INSULATION IN UNCONDITIONED SPACE
separation between | 6" (152MM) | 6" (152MM) | |
intake and exhaust |
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C−Minimum from | 8" (203MM) | 8" (203MM) | |
end of exhaust to | |||
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inlet of intake |
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D−Maximum exhaust | 12" (305MM) | 20" (508MM) | |
pipe length | |||
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3" (76mm) OR
2" (51mm) PVC
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 19
E−Maximum wall support |
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distance from top of each | 6" (152MM) | 6" (152MM) |
pipe (intake/exhaust) |
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FIGURE 20
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