Roof Pitch (X/12) | H (Min. ft) |
Flat to 6/12 | 1 |
6/12 to 7/12 | 1.25 |
Over 7/12 to 8/12 | 1.5 |
Over 8/12 to 9/12 | 2 |
Over 9/12 to 10/12 | 2.5 |
Over 10/12 to 11/12 | 3.25 |
Over 11/12 to 12/12 | 4 |
Over 12/12 to 14/12 | 5 |
Over 14/12 to 16/12 | 6 |
Over 16/12 to 18/12 | 7 |
Over 18/12 to 20/12 | 7.5 |
Over 20/12 to 21/12 | 8 |
Refer to Fig. 4 for graphical reference
Table F: Minimum Height from Roof to Lowest
Discharge Opening
Fig. 5: Minimum Venting Measurements
WARNING: These boilers must not be connected into any portion of mechanical draft systems operating under positive pressure. To do so may cause the flue products to be discharged into the living space causing serious health injury.
For connections to gas vents or chimneys, vent instal- lations shall be in accordance with the Venting of Equipment section of the National Fuel Gas Code, ANSI Z223.1, or applicable provisions of the local building codes.
Common Vents
Manifolds that connect more than one boiler to a com- mon chimney must be sized to handle the combined load. Consult available guides for proper sizing of the manifold and the chimney. At no time should the area be less than the area of the largest outlet.
Fig. 6: Common Venting
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