Installation and Service Manual
Figure 12 – Vent Termination from Flat Roof 10' or Less from Parapet Wall
Provide a minimum clearance of 4 feet (1.2m) horizontally from electric meters, gas meters, regulators, and relief equipment. Never locate the vent cap above or below electric meters, gas meters, regulators, and relief equipment unless a 4 foot (1.2m) horizontal clearance is maintained.
Terminate the venting system at least 3 feet (0.9m) above any forced air inlet within 10 feet (3.05m).
Terminate the venting system at least 4 feet (1.2m) below, 4 feet (1.2m) beside, or 1 foot (30cm) above any door, window, or gravity air inlet into any building.
Locate vent termination at least 8 feet (2.4m) horizontally from any combustion air intake located above the sidewall termination cap.
CAUTION: Pool heaters which are shut down or will not operate may experience freezing due to convective air flow in the flue pipe, through the air inlet, or from negative pressure in the equipment room. In cold climates, operate pump continuously to help prevent freezing of pool heater water. Provide proper freeze protection. See Freeze Protection, page 7.
Figure 13 – Vent Termination from Flat Roof More Than 10' from Parapet Wall
Sidewall Vent Termination Clearances and Location
Locate the bottom of the vent terminal at least 12 inches (30cm) above grade and above normal snow levels. Locate the bottom of the vent terminal at least 7 feet (2.13m) above grade when located adjacent to public walkways. Do not terminate directly above a public walkway.
Do not terminate the venting system in a window well, stairwell, alcove, courtyard, or other recessed area. Do not terminate the venting system below grade.
Locate vent termination at least 3 feet (0.91m) from an inside corner of an
TABLE - B
Flue and Air Inlet Pipe Sizes
Input | Flue | Air Inlet |
Btu / hr | Size | Size* |
|
|
|
500,000 | 6" | 6" |
|
|
|
650,000 | 8" | 8" |
|
|
|
750,000 | 8" | 8" |
|
|
|
990,000 | 10" | 10" |
|
|
|
1,260,000 | 12" | 12" |
|
|
|
1,440,000 | 12" | 12" |
|
|
|
1,800,000 | 14" | 12" |
|
|
|
2,070,000 | 14" | 12" |
|
|
|
*Minimum diameter for air inlet pipe. Installer may increase diameter one pipe size for ease of installation, if needed. Refer to the National Fuel Gas Code (ANSI Z223.1) Vent Tables for additional guidance on vent sizing of fan assisted appliances.
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