Roof (Tee And Upside Down "U"); Combustion Air Pipe; 15: Vertical Termination Of U-Vent And Combustion Air Pipe; Heaters - Rinnai RU80i Manual

Certified PVC/CPVC Vent Termination Options (continued)
NOTE
All figures shown in this section is in reference to flat
roofs. For heights of venting passing through a
pitched roof, refer to NFPA 54/ANSI Z223.1-09 (table
and figure 12.7.2) and/or CSA B149.1-10 (figure 8.1)
PVC/CPVC Roof (Tee and upside down "U")
Terminations:
Locate the vent and intake air termination using the
following guidelines:
1. The total length of the vent or intake air piping
must not exceed the limits given in Table 4-7 (this
document). The equivalent length for 90° elbows
and termination associated with the respective vent
and intake air piping arrangement MUST be
subtracted from total length listed in Tables 4-7.
2. For roof terminations installed as shown in Figure
15, the intake air piping must terminate using a tee
or combination of elbows per figures 14 and 15.
The termination must be installed 12" (30.5 cm),
above roof or the highest anticipated snow level.
3. The vent must terminate vertically with a coupling
to facilitate the bird screen and must be located
12" (30.5 cm) minimum above the combustion air
inlet as shown in Figures 14 and 15.
4. The vent and intake air terminations must be
located a radial distance of 12" minimum (30.5 cm)
from outer wall of vent termination to outer wall of
combustion air intake termination; refer to Figures
14 and 15.
12" min
above air
intake
opening
Figure 14: Vertical Termination of Tee-Vent
and Combustion Air Pipe
Exhaust Vent Termination
Combustion air termination
12" above
anticipated
snow level
or grade
12" min
12" min
above air
intake
opening
Figure 15: Vertical Termination of U-Vent and

Combustion Air Pipe

Multiple Water Heater Installation – Through the
Roof
Locate the vent and intake air termination using the
following guidelines:
1. For installations with multiple Tankless Water
Heaters, refer to Figure 16 for proper exhaust and
combustion air piping placement.
2. Roof penetration of the vent and intake air piping
should be such that the combustion air intake is a
minimum 12" (30.5 cm) from the adjacent vent pipe
of the other water heater. For installations in the
U.S. refer to Figure 16. For installations in Canada,
refer to clearances required by CAN/CSA B149.1.
12" min
12" min
above
air
intake
12" min
Figure 16: Vertical Termination of Multiple
Water Heaters
21
Vent Termination
Combustion air termination
12" above
anticipated
snow level
or grade
12" min
Vent Termination
Combustion air termination
12" above
anticipated
snow level
or grade