8
Use the chart on this page to calculate horizontal runs for vertical rises between 29 and 57 inches. FIGURE 7.
When calculating maximum run lengths, include 10 feet for each 90° elbow or 5 feet for each 45° elbow.
(DO NOT INCLUDE THE FIRST ELBOW DIRECTLY OFF THE UNIT.)
FIGURE 7
REQUIRED
VERTICAL
RISE FROM
FIREPLACE
TO FIRST
ELBOW IN
INCHES
OFFSET INSTALLATION EXAMPLE
FIGURE 9
CALCULATED HORIZONTAL VENT RUN IN FEET
SPECIAL INSTALLATION EXAMPLE
When a horizontal run is introduced, even though the termi- nal may be vertical, the installation must be considered
HORIZONTAL.
A through the roof installation requires a total 5 foot rise. FIGURE 8. The location of the fireplace dictates a horizontal run of 5 feet. What is the required vertical rise to the centre of the initial 90° elbow?
The total run is: | 5 ft. (through the roof vertical rise) | |
| 10 ft. (90° elbow) | |
| 5 ft. (horizontal run) |
|
| 20 ft. (total run) | |
Using the chart, will determine that a 57 inch minimum vertical rise immediately off the unit is required for satisfactory venting conditions.
ALTHOUGH THE IMMEDIATE
VERTICAL RUN MAY BE
GREATER THAN 57 INCHES, THE
MAXIMUM COMBINATION OF
HORIZONTAL AND VERTICAL
RUNS, BEYOND THE 57 INCHES,
MUST NOT EXCEED 20 FEET.
FIGURE 8
57"
48" |
|
|
second | run | |
| ||
first | run | |
| ||
72" | ||
If a first run of 72 inches is required, using the "First Vent Run" on the chart shows that
amaximum second run of
48 inches is allowable.
IF NECESSARY, THE FIRST RUN AND THE SECOND RUN MAY BE REVERSED.
FIGURE 10