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.
between the end of the exhaust pipe and the end of the intake pipe without a termination elbow is 8" and a minimum distance of 6" with a termination elbow. See figures 28 and 29.
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-
Inches(mm)
3"(76mm) MAX.
SIZE TERMINATION PIPE PER TABLE 8.
UNCONDITIONED
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 27.
8" (203mm) MIN
12" (305mm) ABOVE |
AVERAGE SNOW |
ACCUMULATION |
ATTIC SPACE
1/2" (13mm) FOAM
INSULATION IN UNCONDITIONED SPACE
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 25 through 37 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.
3" (76mm) OR
2" (51mm) PVC
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 25
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 25).
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 8.
2" EXTENSION FOR 2" PVC PIPE
1" EXTENSION FOR 3" PVC PIPE
FURNACE
INTAKE
PIPE
4’’
FURNACE
EXHAUST
PIPE
GLUE EXHAUST
END FLUSH INTO
TERMINATION
1−1/2" ACCELERATOR (all −070 and −090 units)
TABLE 8
EXHAUST PIPE TERMINATION SIZE REDUCTION
ML193 | Exhaust Pipe Size | Termination | |
MODEL | Pipe Size | ||
| |||
|
|
| |
*045 and *070 | 2" (51mm), 2−1/2" (64mm), | 1−1/2" (38mm) | |
*090 | 3" (76mm) | 2" (51mm) | |
| |||
110 | 3" (76mm) | 2" (51mm) |
*ML193DF−045, −070 and −090 units with the flush−mount termination must use the 1−1/2"accelerator supplied with the kit.
5 − On field−supplied terminations for side wall exit, ex- haust piping may extend a maximum of 12 inches (305mm) for 2" PVC and 20 inches (508mm) for 3" (76mm) PVC beyond the outside wall. Intake piping should be as short as possible. See figures 28 and 29.
NOTE − Care must be taken to avoid recirculation of exhaust back into intake pipe.
6 − On field supplied terminations, a minimum distance
FLUSH−MOUNT SIDE WALL TERMINATION KIT 51W11
FIGURE 26
7 − If intake and exhaust piping must be run up a side wall to position above snow accumulation or other ob- structions, piping must be supported every 24" (610mm) as shown in figures 28 and 29. In addition, close coupled wall termination kits must be extended for use in this application. See figures 35 and 36. When exhaust and intake piping must be run up an outside wall, the exhaust piping must be terminated with pipe sized per table 8.The intake piping may be equipped with a 90° elbow turndown. Using turndown will add 5 feet (1.5m) to the equivalent length of the pipe.
8 − A multiple furnace installation may use a group of up to four terminations assembled together horizontally, as shown in figure 32.
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