Multiple Concentric Vent Installations; Vent Pipe Length - American Water Heater Powerflex Installation And Operating Manual

ORIENTATION OF EXHAUST PIPING AND COMBUSTION AIR PIPING RELATIVE
TO EACH OTHER MAY BE VERTICAL (AS SHOWN) OR AT ANY OTHER ANGLE
TO SUIT THE INSTALLATION.
EXHAUST
COMBUSTION
AIR
Figure 24
VENT DIA.
2"
3"
Table 2
Figure 24 illustrates the concentric vent kit for a horizontal
(side wall) installation. To prevent rain water from entering
the exhaust outlet, slope the vent kit at a downward
pitch of 1/4" per 5' away from the inside wall. Ensure the
combustion air intake location is above the anticipated
snow level.

Multiple Concentric Vent Installations

When two concentric vent kits are being installed, the vent
hood centers shall be either less than 9.5" apart or more
than 43.5" apart. Spacings between 9.5" and 43.5" are not
allowed due to the possibility of exhaust cross circulation
(see Figure 25).
When more than 2 kits are installed only 2 of them shall
be less than 9.5" apart. Never install 3 termination kits
together less than 9.5" apart (see Figure 26).
WALL
Figure 25
28
STRAP (FIELD
SUPPLIED)
SLOPE 1/4" OVER 5'
ELBOW (FIELD
SUPPLIED)
P/N
9008586005
9006328005
O R
9 .5 " M A X
4 3 .5 " M IN
NOTE: IF AN
ELBOW IS
REQUIRED
BY LOCAL
CODES
INSTALL
SCREEN
IN ELBOW
INSTEAD OF
CONCENTRIC
VENT
EXHAUST.
SCREEN
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COMBUSTION
AIR
WALL
NOTE: IF AN ELBOW IS REQUIRED BY
LOCAL CODES INSTALL SCREEN IN ELBOW
INSTEAD OF CONCENTRIC VENT EXHAUST.
9 .5 " M A X ..
Figure 26

Vent Pipe Length

The maximum allowable pipe lengths for air intake and
exhaust are listed in Table 3. The specifi ed maximum
lengths are for each of the intake and exhaust systems and
not for the combined lengths of both systems. In addition,
each system requires a 45° long sweep elbow termination
with a restrictive screen. Minimum pipe length is 3' with a
minimum of one 90° elbow per side (intake and exhaust).
1. Determine termination type and pipe size.
2. Determine number of elbows in vent system. Do not
include termination elbow. Calculate the maximum
equivalent length of the exhaust and air intake system.
90° SHORT SWEEP ELBOW
(MORE RESTRICTIVE)
Figure 27
PIPE NIPPLE (USE
WITH ELBOW)
90° ELBOW
(SEE LOCAL
CODES)
1" MAXIMUM
SCREEN INSIDE
4 3 .5 " M IN .
SCREEN WALL
90° LONG SWEEP ELBOW
(LESS RESTRICTIVE)
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