D. How to Use the Vent Graph
1.Measure the distance from the top of appliance 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 top of the appliance to the center of the 90° elbow is 7 ft. (2 m), the horizontal run to the outer wall flange must not exceed 13 ft. (4 m).
Example 2: If the vertical dimension from the top of the appliance is 21 ft. (6.4 m), the horizontal run to the outer wall flange must not exceed 9 ft. (3 m).
4.Each 90° elbow is equivalent to 3 ft. (914 mm) of vent pipe and each 45° elbow is equivalent to 1 ft. (305
mm)of vent pipe, and must be subtracted from vent pipe run. A single vertical to horizontal 90° elbow is already calculated into the allowable 15 ft. (5 m) run. Each additional 90° elbow reduces the maximum horizontal distance by 3 ft. (914 mm).
Example: The use of three elbows would reduce the allowable horizontal run to 9 ft. (3 - 1 = 2 elbows x 3 ft. = 6 ft.; 15 ft. max. - 6 ft. = 9 ft. max.)
E. Venting Guidelines
•The maximum horizontal vent run is 15 ft. (5 m) when the vertical vent rise is 10 ft. (3 m).
•The minimum horizontal vent run is
•Horizontal sections require a 1/4 in. (6 mm) rise for every 12 in. (305 mm) of horizontal travel.
•Horizontal sections require noncombustible support every 3 ft. (914 mm), e.g. wall strap.
•Wall thickness: Minimum 4 in. (102 mm). Maximum 20 in. (508 mm).
•Vent Diameter: Exterior
EXCEPTION FOR REAR VENT KIT (Snorkel Kit SLK-
SNKD), HORIZONTAL INSTALLATION:
•The maximum horizontal vent run is 3 ft. (914 mm).
•The maximum horizontal vent run with a 45° elbow is 2 ft. (610 mm).
•No external minimum rise is required. The minimum horizontal vent run is
•For any vertical rise when rear venting, a minimum of 2 ft. (610 mm) vertical must be used prior to any horizontal run.
•Snorkel Kit
EX. 2
VERTICAL DISTANCE
FROM APPLIANCE TO THE 90º ELBOW
EX. 1
35' |
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34' |
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32' |
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30' |
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28' |
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26' |
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24' |
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22' |
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20' |
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18' |
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| RESTRIC | D |
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| TOTAL HORIZONTAL RUN TO | |||
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16' |
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| OUTSIDE OF EXTERIOR WALL | ||||
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14' | TE | REQUIRE |
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12' | VENT |
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| To adjust the vent restrictor |
PLA |
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10' |
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| plate, see page 34. |
8' |
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6' |
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4' |
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2' |
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0' |
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| 4' |
| 6' | 8' | 10' | 12' | 14' | 15' | ||
(MIN) |
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Figure 5.2
6 ft. (2 m) Minimum Vertical Termination
C
L
CL For rear vent or top of appliance for top vent.
3 ft. (914 mm) Maximum Horizontal run with no vertical pipe and with 1/4 in. (6 mm) rise per foot.
6 in. (152 mm) Minimum starter pipe
12 | Heat & Glo • Paloma • |
