R
C. Equivalent Feet of Pipe
The table below can help you calculate the equivalent feet of pipe which is a method used to determine pellet vent size. See
Figure 14.1.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause injury or property damage. Refer to the owner’s information manual provided with this appli- ance. For assistance or additional information consult a qualified installer, service agency or your dealer.
Example of 3
2 ft. | Pellet Venting | # of | Feet of | Multiplied | Equivalent | Components |
Component | Elbows | Pipe | By | Feet | Equivalent Feet | |
| 90o Elbow or Tee | 3 |
| X | 5 | 15 |
3 ft. | 45o Elbow |
|
| X | 3 |
|
Horizontal Pipe |
| 7 | X | 1 | 7 | |
| Vertical Pipe |
| 2 | X | 0.5 | 1 |
Total Equivalent Feet
23
2 ft.
Note: This is a generic example and is not intended to represent any specific fuel type.
2 ft.
Figure 14.1
D. Pipe Selection Chart
The chart will help you in determing proper venting size according to the equivalent feet of pipe calcuated above and the altitude above sea level of this installa- tion. See Figure 14.2.
Locate the calculated equivalent feet of pipe on the vertical left side of the chart. Move to the right horizontally on the chart until you reach your altitude above sea level.
If you fall below the diagonal line, 3 or 4 inch (76 to 102mm) pipe may be used. If it is anywhere above the diagonal line, a 4 inch (102mm) diameter pipe is requried.
The chart reveals that a 90° elbow is 5 times as restrictive to the flow of exhaust gases under positive pressure as 1 foot of horizontal pipe, and a foot of horizontal pipe is twice as restrictive as a foot of vertical pipe.
| 30 |
| 4 in. (102mm) Diameter Pipe Only |
| ||||||
|
|
|
| |||||||
Example 1 |
|
|
|
|
|
|
|
|
|
|
| 20 |
|
|
|
|
|
|
|
|
|
Equivalent Pipe |
|
|
|
|
|
|
|
|
| |
Length In Feet |
|
|
|
|
|
|
|
|
|
|
Example 2 | 10 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
| 3 in. or 4 in. (76mm or 102mm) Diameter Pipe |
|
| |||||||
| 0 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 1 | |||||||||
ALTITUDE IN THOUSANDS OF FEET
Figure 14.2
Example 1: If the equivalent length of pipe is 23 feet (7m)with altitude of 8,000 feet (2438m) you must use 4 inch (102mm) diameter type “L” or “PL” vent.
Example 2: If the equivalent length of pipe is 12 feet (3.7m) with al- titude of 6,000 feet (1829m) you may use 3 or 4 inch (76 to 102mm) diameter type “L” or “PL” vent
WARNING
Fire Risk.
Do NOT pack insulation or other combustibles between firestops.
•ALWAYS maintain specified clearances around venting and firestop systems.
•Install firestops as specified.
Failure to keep insulation or other material away from vent pipe may cause fire.
Page 14 | February 3, 2010 |
