Bosch C 1210 ES - Page 12

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Installation instructions
3.3.2 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 feet (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 5 if using 3" diameter
venting. Refer to table 6 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 combus-
tion air piping:
Diam. Aproved 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 4 Venting specifications for intake and exhaust
3"
Venting Maximum
allowable
Exhaust
pipe length
Maximum
allowable
Combustion
air pipe
length
Elbow
Equivalency
90° 45°
Twin pipe
system
31ft 31ft 5 ft 3 ft
Concen-
tric system
23ft 23ft 5 ft 3 ft
Table 5 Maximum Allowable Exhaust and Combustion
Air Lengths for 3" venting
4"
Venting Maximum
allowable
Exhaust
pipe length
Maximum
allowable
Combustion
air pipe
length
Elbow
Equivalency
90° 45°
Twin pipe
system
63ft 63ft
2.5ft 1.5ft
Concen-
tric system
23ft 23ft
2.5ft 1.5ft
Table 6 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 6
Table 7
i
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 7 above.