16
No. of
Elbows
3
2
1
4
Max. Straight Vent Length**
3" (75mm) PVC or CPVC
Max. Straight Vent Length**
4" (100mm) PVC or CPVC
** Not including the concentric termination
16' (4.8m)
N / A
22' (6.6m)
28' (8.4m)
30' (9.0m)
N / A
36' (10.8m)
42' (12.6m)
Maximum Vent Length Adjustment Dip switches.
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
0.00
0.90
1.80
2.70
3.60
4.50
5.40
6.30
7.20
8.10
9.00
9.90
10.80
11.70
12.60
m
1
0
2
3
ft
Vent length***
Elbows
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
N /A
Number of
pieces****
-5%
-5%
3
3
0%
3
3
4
4
4
4
4
4
4
4
4
4
4
3
3
0%
4
4
4
4
4
4
4
4
4
4
4
4
4
-3%
-3%
-3%
-3%
-3%
-5%
4
4
4
4
4
4
4
4
4
4” Pipe
<Maximum Vent Length and Reduced Input Configurations>
*** Refer to page 13 for 3" pipe Maximum Vent Length Adjustment Dipswitches table.
3
4
Short length using 4" (100mm) pipe
Long length using 4" (100mm) pipe
****Table assumes straight vent pieces are 3’ (0.9m) each.
Shorter or longer vent pieces may also be used up to the maximum
allowed vent length.
H
H
H
H
H
H
H
Hanger
Straps
3" (75mm) or
4" (100mm)
Intake*
Horizontal Vent Termination- 3" (75m) Concentric PVC/CPVC Termination
3" (75mm) or
4" (100mm)
Exhaust*
The concentric termination TWHHORCONC may be
shortened, but not lengthened from its original
factory supplied length.
The concentric termination may only be used
for horizontal terminations.
Terminate at least 12" (300mm) above grade or
above snow line.
Terminate at least 7' (2.1m) above a public walkway,
6' (1.8m) from the combustion air intake of any
appliance, and 3' (0.9m) from any other building
opening, gas utility meter, service regulator etc.
Terminate at least 3' (0.9m) above any forced air
inlet within 10' (3m), 1' (0.3m) below, 1' (0.3m)
horizontally from or 1' (0.3m) above any door,
window, or gravity air inlet into any building per
National Fuel Gas Code ANSI Z223.1/NFPA 54.
Slope the horizontal vent 1/4" upwards for every
12" (300mm).
Use a condensation drain if necessary.
In the Commonwealth of Massachusetts a carbon
monoxide detector is required for all side wall
horizontally vented gas fuel equipment.
Please refer to Technical Bulletin TB 010606 for full
installation instructions.
Slope vent
Upwards
* 4" (100mm) pipe requires the use of a reducing coupling
just prior to the termination.
H
H
H
H
3" (75mm) or 4" (100mm) PVC or CPVC pipe
may be used with the concentric termination.
Maintain the same vent pipe diameter from the
water heater flue to the termination.
Do not exceed the maximum vent lengths as
specified in this section.
When using 4" (100mm) pipe, it will be necessary
to use 4" (100mm) x 3" (75mm) reducing couplings
and a short section of 3" (75mm) pipe to connect to
the termination.
Use no more than a 6" (150mm) section of pipe to
make the connection between the reducing
couplings and the termination.
H
Install a securing strap to prevent movement of
the termination.
There must be a 1" (25mm) to 4" (100mm) clearance
between the outside wall and the air intake section
of the termination as illustrated on the left.
1" (25mm) to
4" (100mm)
Insert Bird Screen ***
in End of Termination
*** Not supplied with
water heater,
order separately.
Strap
