John Wood Polaris Commercial High-Efficiency - Manual (Page 11)

11
VERTICAL TERMINATIONS
When 3 inch pipe is used between the water heater and the
roof, reduce it to 2 inch pipe before penetrating the roof.
A maximum of 18 inches (45.7 cm) of 2 inch pipe may be
used between the 3 inch transition and the inside of the
roof.
The vertical inlet air termination requires a return bend
or two short or long sweep radius 90 elbows to keep the
inlet downward and prevent entry of rain. These elbows
are considered part of the termination and should not be
included when calculating the maximum allowable vent
pipe length. Refer to figure 9 for the proper location of the
air inlet with respect to the exhaust outlet termination. The
vertical exhaust outlet termination is a 2 inch (30.5 cm) pipe
which terminates at least 12 inches (30.5 cm) above the
inlet air termination.
The air inlet and exhaust outlet terminations must be at
least 12 inches (30.5 cm) above the roof line or anticipated
snow levels. See figure 9 below.
Note: See “Venting Additional Polaris
® Units” below if
installing more than one Polaris ® gas water heater.
Venting Additional Polaris ® Units
When using two (2) Polaris ® units, install vent terminations
using either Method A or Method B below:
When using three or more Polaris ® units, install vent
terminations per Method C or Method D:
Figure 9: Vertical Termination
Notes:
1. Support Horizontal Pipe Every
Four Feet (1.2 m). Support Vertical
Pipe Every Six Feet (1.8 m).
2. When Using 3 Inch Pipe, Reduce To
2 Inches Before Penetrating The
Roof.
3. 18 Inch (45.7 cm) Maximum When
Using 2 Inch Pipe.
4. Increase The 12 Inch (30.5 cm)
Minimum Above Grade To Keep
Terminal Openings Above Anticipated
Snow Levels.
4” (10 cm) Max.
12” (30.5cm) Min.
Above Roof or
Anticipated Snow
Level. See Note 4.
12” (30.5 cm) Min.
12” (30.5 cm)
Min.
4” (10 cm)
Max.
12”
(30.5 cm)
Min.
*
*
3” (7.6cm) Max.
4” (10cm)
Max.
3”
(7.6 cm)
Max.
4”
(10cm)
Max.
36” (91.4 cm)
Minimum 3” (7.6 cm) Max.
4”
(10cm)
Max.
3”
(7.6 cm)
Max.
4”
(10cm)
Max.
4”
(10cm)
Max.
36” (91.4 cm)
Minimum
4”
(10cm)
Max.
4”
(10cm)
Max.
4”
(10cm)
Max.
36” (91.4 cm)
Minimum
36” (91.4 cm)
Minimum
Figure 9A, 9B
Figure 9C, 9D