Installation instructions
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13
6 720 644 887 (2013/02)
C 1210 ES/ESC
4.3.2
Vent specifications
Establish vent clearances that comply with the vent manufacturer's
specifications and all applicable national/local codes.
Venting specifications
[*]
ULC S636-95, UL1738 certified
Condensate drain requirements
An external condensate drain (not supplied with the heater) must be
installed under the following conditions:
• All vertical terminating vent installations.
• Horizontal terminating vent installations where the total linear vent
length is greater than 6 feet (1.8 m).
• Vent installations where any section of the exhaust vent pipe passes
through an unconditioned space.
Minimum combustion air and exhaust pipe length
The minimum exhaust pipe length is 1 foot (0.3m) of straight vent pipe.
The minimum combustion air pipe length is one 90° elbow.
Maximum combustion air and exhaust pipe length
The following tables display the maximum allowable straight pipe
lengths for combustion air and exhaust piping with consideration to the
number of elbows used. Reduce the equivalent length for each elbow
used from the maximum allowable length depending on the system
used. Refer to table 8 if using 3" diameter venting. Refer to table 9 if
using 4" diameter venting.
Use of elbows
It is recommended to limit the amount of elbows used in the exhaust and
combustion air piping to reduce friction in the air flow. The following lists
the maximum amount of 90° elbows allowed in either the exhaust or
combustion air piping:
Calculation example for 3" venting:
Exhaust
Combustion air
Diam.
Approved terminals
E
x
h
a
u
s
t
3 or 4 inches
“T” terminal
90° elbow
PVC Flue Cap*(ECAP321)Vertical terminations
only 3" diameter only
Concentric (196016)
I
n
t
a
k
e
3 or 4 inches
“T” terminal
90° elbow
PVC Flue Cap*(ECAP321)Vertical & horizontal
terminations approved 3" diameter only
Concentric (196016)
Table 7 Venting specifications for intake and exhaust
3" Venting
Maximum
allowable
Exhaust pipe
length
Combustion air
pipe length
Elbow
Equivalency
90°
45°
Twin pipe
system
31ft
31ft
5 ft
3 ft
Concentric
system
23ft
23ft
5 ft
3 ft
Table 8 Maximum Allowable Exhaust and Combustion Air Lengths for 3"
venting
4" Venting
Maximum
allowable
Exhaust pipe
length
Combustion air
pipe length
Elbow
Equivalency
90°
45°
Twin pipe
system
63ft
63ft
2.5ft
1.5ft
Concentric
system
43ft
43ft
2.5ft
1.5ft
Table 9 Maximum Allowable Exhaust and Combustion Air Lengths for 4"
venting
Max. number of 90° elbows
3" venting
4" venting
Twin pipe system
5
7
Concentric system
4
7
Table 10
Two 45° elbows are equal to one 90° elbow. Any
combination of 45° and 90° elbows may be used in
the vent system as long as the combination does not
exceed the maximum listed in table 10 above.
System used
Concentric
Number of 90° elbows needed:
1
Number of 45° elbows needed:
2
Table 11
Calculation of example
Max. length
23’
90° elbow reduction
- 5’
sub-total =
18’
45° elbow reduction
- 6’
Total =
12’
Table 12
For this example, the maximum allowable exhaust pipe
length is
12 feet
.
System used
Concentric
Number of 90° elbows needed:
2
Number of 45° elbows needed:
1
Table 13
Calculation of example
Max. length
23’
90° elbow reduction
- 10’
sub-total =
13’
45° elbow reduction
- 3’
Total =
10’
Table 14
For this example, the maximum allowable combustion
air pipe length is
10 feet
.
