U.S. HORIZONTAL VENT CLEARANCES
WARNING
VENT HOOD(S) MAY BE
EXTREMELY HOT
DURING OPERATION.
FIGURE 15.
2.A venting system should terminate at least 3 feet above any forced air inlet located within 10 feet.
3.The venting system should terminate at least 4 feet below, 4 feet horizontally from or, 1 foot above any door, window or gravity air inlet into any building.
4.The manufacturer also recommends that the vent system termination not be installed closer than 18” from an inside corner of an L shaped structure and not be less than 1 foot above grade. The vent should terminate a minimum of 12’’ above expected snowfall level to prevent blockage of vent termination.
5.The vent termination should not be mounted directly above or within 3 feet horizontally from an oil tank vent or gas meter to avoid potential
Plan the vent system layout so that proper clearances are maintained from plumbing and wiring.
Vent pipes serving power vented appliances are classified by building codes as “vent connectors”. Required clearances from combustible materials must be provided in accordance with information in this manual under LOCATION OF HEATER and INSTALLATION OF VENT SYSTEM, and with the National Fuel Gas Code and local codes.
PLANNING THE VENT SYSTEM
Plan the route of the vent system from the discharge of the blower to the planned location of the vent terminal.
1.Layout the total vent system to use a minimum of vent pipe and elbows. Take into consideration that an elbow will be necessary to make the first vent pipe connection to the power venter outlet, see Figure 6.
2.This water heater is capable of venting the flue gases the equivalent of thirty (30) feet of 3 inch pipe or
TABLE 1.
Number of | 3” Maximum | 4” Maximum |
90° Elbows | Pipe (Feet) | Pipe Feet |
ONE (1) | 25 | 92 |
TWO (2) | 20 | 84 |
THREE(3) | 15 | 76 |
FOUR (4) | 10 | 68 |
FIVE (5) | - - - | 60 |
Minimum of one (1) elbow and 2 feet of straight pipe must be installed for 3” and 4” pipe.
NOTE: The equivalent feet of pipe listed above are exclusive of the “45° Elbow” termination. That is, the termination “45° Elbow”, with installed screen, is assumed to be in the system and the remainder of the system must not exceed the thirty (30) equivalent feet of 3 inch pipe or
3.The blower discharge adapter is made to accept only straight sections of 3” pipe. To start a minimum of 2 inches of 3” pipe must be attached to the blower discharge. See Figure 6.
If using 3 inch vent pipe:
A minimum of 2 inches, maximum of 4 feet of 3” pipe must be attached to the blower before the first
If using 4 inch vent pipe:
Two inches of 3” pipe must be attached to the blower discharge. A 4” x 3” reducer is added and then up to maximum 4 feet of 4 inch pipe added before the first elbow. An additional 4” x 3” reducer and (1) foot of 3” pipe must be added to the end of the vent system before terminating into the 3” 45° elbow. The total system cannot exceed 100 equivalent feet of 4” venting, where each elbow is equal to 8 feet of straight pipe.
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