Initial Installation
QUALIFIED INSTALLERS ONLY
8. Continue to add pipe sections until the height of the vent cap meets the minimum code requirements. Refer to Figure 38 and Table 6. Note that for steep roof pitches, the vent height must be increased. In high wind conditions, nearby trees, adjoining roof lines, steep pitched roofs, and other similar factors can result in poor draft, or down drafting. In these cases, increasing the vent height may solve the problem.
9. Slip the storm collar over the pipe, and push it down to the top of the roof flashing as shown in Figure 37. Use the
10. Twist-lock the vent cap.
Table 8: Minimum ‘H’ for Figure 38.
Figure 38: Height of Vertical Termination;
Reference Table 8.
Roof Pitch | Minimum Height | |
|
|
|
| Feet | Meters |
|
|
|
Flat to 7/12 | 1 | 0.3 |
|
|
|
Over 7/12 to 8/12 | 1.5 | 0.46 |
|
|
|
Over 8/12 to 9/12 | 2 | 0.61 |
|
|
|
Over 9/12 to 10/12 | 2.5 | 0.76 |
|
|
|
Over 10/12 to 11/12 | 3.25 | 0.99 |
|
|
|
Over 11/12 to 12/12 | 4 | 1.22 |
|
|
|
Over 12/12 to 14/12 | 5 | 1.52 |
|
|
|
Over 14/12 to 16/12 | 6 | 1.83 |
|
|
|
Over 16/12 to 18/12 | 7 | 2.13 |
|
|
|
Over 18/12 to 20/12 | 7.5 | 2.29 |
|
|
|
Over 20/12 to 21/12 | 8 | 2.44 |
|
|
|
NOTES:
(a)If an offset is necessary in the attic to avoid obstructions, it is important to support the vent pipe every 3 feet (91 cm), to avoid excessive stress on the elbows, and possible separation. Wall straps are available for this purpose (see Figure 39).
(b)When ever possible, use 45° degree elbows instead of 90° degree elbows. The 45° degree elbow offers less restriction to the flow of flue gases and intake air.
(c)For multi story installations. A ceiling firestop is required at the second floor, and any subsequent floors (see Figure 40). The opening should be framed to 10” (25.4 cm) x 10” (25.4 cm) inside dimensions, in the same manner as shown in Figure 36.
(d)Any occupied areas above the first floor, including closets and storage spaces, which the vertical vent passes through, must be enclosed. The enclosure may be framed and sheet rocked with standard building materials. However consult the appliance manufactures installation instructions for the minimum allowable clearance between the outside of the vent pipe, and the combustible surfaces of the enclosure. Do not fill any required air spaces with insulation.
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