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DV425TR DIRECT VENT ROOM HEATER
02/01 Page 35 250-5533
Step 7.
Continue to assemble pipe sections until
the height of the vent cap (H) (Figure 15) meets
the minimum code requirements as outlined in
the current CAN/CGA-B149 Installation Codes (in
Canada), the National Fuel Gas Code NFPA 54/ANSI
Z223.1 (in USA), or local codes. Note that for steep
roof pitches, the vent height must be increased.
See Table 1 below. In high wind conditions, nearby
trees adjoining rooflines, steep pitched roofs, and
other similar factors can result in poor draft, or down
drafting. In these cases increasing the vent height
may solve this problem.
VERTICAL INSTALLATION, cont.
Fig. 15
Dimension "H"
Obtained From
Table 1
TABLE 1
MINIMUM HEIGHT
ROOF PITCH FEET METERS
Flat to 7/12 1 0.30
Over 7/12 to 8/12 1.5 0.46
Over 8/12 to 9/12 2 0.61
Over 9/12 to 10/12 2.5 0.76
Over 10/12 to 11/12 3.25 0.99
Over 12/12 to 14/12 5 1.52
Over 14/12 to 16/12 6 1.83
Over 16/12 to 18/12 7 2.13
Over 18/12 to 20/12 7.5 2.29
Over 20/12 to 21/12 8 2.44
The height of the vent cap must meet the
minimum building code requirements
described above.
H