D. How to Use the Vent Graph
1.Measure the vertical distance from the center line of the flue pipe to the center of the 90° elbow. On the graph below, draw a horizontal line from that measurement on the vertical axis across until it intersects with the slanted line.
2.From the point of this intersection, draw a vertical line to the bottom of the graph.
3.The point at which this line meets the bottom line of the graph is the maximum length of the horizontal run.
EXAMPLE 1: If the vertical dimension from the center line of the flue vent to the center of the 90° elbow is 7 ft. (2m), the horizontal run to the outer wall flange must not exceed 16 ft. (5m).
EXAMPLE 2: If the vertical dimension from the center line of the flue vent is 21ft. (6m), the horizontal run to the outer wall flange must not exceed 12 ft. 10 in. (4m).
4.Each 90° elbow is equivalent to 3 ft. (914mm) of vent pipe and each 45° elbow is equivalent to 1ft. (305mm) of vent pipe, and must be subtracted from the vent pipe run. A single horizontal to vertical 90° elbow is already calculated into the allowable 20 ft. (6m) run. Each additional 90° elbow reduces the maximum horizontal distance by 3 ft. (914mm).
EXAMPLE: The use of 3 elbows would reduce the allowable horizontal run to 9 ft. (3
E. Venting Guidelines
NOTES
The maximum horizontal vent run is 20 ft. (6m) when the vertical vent rise is 10 ft. (3m).
The minimum horizontal vent run is 6 in. (152mm) Horizontal sections require a 1/4 in. (6mm) rise for every 12 in. (305mm) of horizontal travel.
Exterior Vent Diameter =
Horizontal sections require noncombustible support every 3 ft. (914mm), e.g. wall straps.
For any vertical termination a minimum of 6 ft. (2m) vertical must be used.
EXCEPTIONS FOR HORIZONTAL INSTALLATIONS: *When installing the Topaz in a rear vent configuration with no vertical rise, a Snorkel Kit must be used.
*The maximum horizontal vent run is 3 ft. (914mm). *The maximum horizontal vent run with a 45° elbow is 2 ft. (609mm).
*The minimum horizontal vent run is 6 in. (152mm).
INDIVIDUALINSTALLATIONS MAYVARY. PERCENTAGE CLOSED BASED ON FULL RANGE OF DAMPER TRAVEL.
NOTE: If your installation falls within the
*In the Commonwealth of Massachusetts, the word damper shall be replaced with the words flue restrictor.
40 ft. (12m) | 40' |
Maximum Vertical | 39' |
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Example 2 | 22' |
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VERTICAL DISTANCE | 18' |
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FROM APPLIANCE TO | 14' |
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90° ELBOW | 12' |
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Example 1 | 8' |
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6 in. (152mm) Minimum | 2' | 4' | 6 ' | 8' | 10' | 12' | 14' 15' 16' | 17' | 18' | 19' | 20' | |
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CL For rear vent or top of | 6 in. (152mm) Minimum starter pipe | |
appliance for top vent | ||
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Figure 5.2
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