Empire Heating Systems PVS18(N,P)-1 Owner's Manual And Installation Instructions page 31

Notice: The vent terminal elbow does not contribute to the
overall vent length measurement. For each 45° elbow in-
stalled in the run, the length of the run MUST be reduced by
1.5 feet (45 cm). Reduce the length of the run three feet (91.4
cm) for every 90° elbow.
All vent components are supplied by the installer.
Calculation example of vent run maximum 50 feet
Figure 50 displays a two-pipe vertical installation. The first 90° el-
bow must be added to the total vent length. The equivalent length
of the second 90° elbow also needs to be added to the total length.
The equivalent length of the third elbow does not need to be added
since it is the termination. The total horizontal vent length of the
flue system is eleven feet, and the total vertical length is 33 feet.
The two 90° elbows are equivalent to six feet, bringing the total to
50 feet.
32084-1-0713
WALL FURNACE INSTALLATION
DIRECT VENT EXAMPLES
Figure50
Notice: For vertical termination, the exhaust must be a minimum
of three inches above the inlet air pipe. The inlet must be at least
twelve inches from the roof line or the maximum expected snow
level as indicated in Figure 51.
ROOF PITCH
Flat to 6/12
6/12 to 7/12
Over 7/12 to 8/12
Over 8/12 to 16/12
Over 16/12 to 21/12
Determining Minimum Vent Height Above the Roof
WARNING
Major U.S. building codes specify minimum chimney and/or vent
height above the rooftop. These minimum heights are neces-
sary in the interest of safety. These specifications are summa-
rized in Figure 51.
H (Min.)
12" (305 mm)
15" (381 mm)
18" (457 mm)
24" (610 mm)
36" (914 mm)
Figure 51
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