Installation instructions
a 3" or 4" pipe from the outside. See Chapter 3.5 for more direction on combustion air.
BTo reduce pressure differentials between the exhaust and combustion air intake, it is recommended that both terminators exit on the same plane. See Fig. 14 for an example horizontal twin pipe termination and Fig. 15 for the vertical twin pipe termination example.
Fig. 14 Horizontal twin pipe termination
Fig. 15 Vertical twin pipe termination
3.6.5Vertical terminations
Warning: Failure to install a condensate drain may result in damage not covered by the manufacturer's warranty. See chapter 3.6.3.
An approved vent terminator must be used. See Table 5 for known approved vertical vent terminations.
Horizontal runs
Any gas vent section that is greater than 45 degrees from the vertical is considered horizontal. Horizontal sections must slope upwards from heater at least ¼ inch for every foot of its horizontal length and be prop- erly supported to allow condensate to be collected by condensate drains.
Vent terminations
BNo pipe joints other than the termination connections should be exposed to the outdoors. See vent manu- facturer instructions for details.
BUse of two 90° elbows
BScreening (no smaller than 1/4" mesh) is recom- mended on candy cane termination.
BExhaust should terminate above and must be a mini- mum of 3 feet from must intake termination.
BThe exhaust vent must terminate above the roof sur- face with an approved vent cap not less than 3 feet (0.6 m) above the highest point where it passes through the roof and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction within 10 feet (3.1m). See Fig. 16 and Table 5.
Fig. 16 Vertical | vent | terminations | clearances | ||
(Combustion air piping not shown) | |||||
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GAS VENT TERMINATIONS FOR LISTED VENT |
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| CAPS |
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Roof pitch |
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| H (min.) | meters |
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| feet |
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Flat to 6/12 |
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| 1.0 | 0.30 |
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6/12 to 7/12 |
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| 1.25 | 0.38 |
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Over 7/12 to 8/12 |
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| 1.5 | 0.46 |
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Over 8/12 to 9/12 |
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| 2.0 | 0.61 |
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Over 9/12 to 10/12 |
| 2.5 | 0.76 |
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Over 10/12 to 11/12 |
| 3.25 | 0.99 |
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Over 11/12 to 12/12 |
| 4.0 | 1.22 |
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Over 12/12 to 14/12 |
| 5.0 | 1.52 |
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Over 14/12 to 16/12 |
| 6.0 | 1.83 |
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Over 16/12 to 18/12 |
| 7.0 | 2.13 |
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Over 18/12 to 20/12 |
| 7.5 | 2.27 |
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Over 20/12 to 21/12 |
| 8.0 | 2.44 |
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Table 5 Termination heights at various roof pitches
Interior masonry chimneys
The single wall stainless steel exhaust vent pipe must be permanently mounted inside the masonry chimney.
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