Bosch C 950 Installation Manual page 13

4.3.2 Vent specifications
Establish vent clearances that comply with the vent manufacturer's
specifications and all applicable national/local codes.
Venting specifications
Diam.
E 3 or 4 inches
x
2, 3 or 4 inches
h
a
3 inches PVC Flue Cap*(ECAP321)Vertical terminations
u
s
t
3 or 4 inches Concentric (196016, 196006)
I 3 or 4 inches
n
2, 3 or 4 inches
t
a
3 inches PVC Flue Cap*(ECAP321)Vertical & horizontal
k
terminations approved 3" diameter only
e
3 or 4 inches Concentric (196016, 196006)
Table 7 Venting specifications for intake and exhaust
[*] ULC S636-95, UL1738 certified
Condensate drain requirements
When the Water Heater is installed in a residential single family dwelling
without direct recirculation an external condensate drain is not required.
If the Water Heater is installed in an application other than a residential
single family dwelling an external condensate drain (not supplied with
the Water Heater) is required in the following circumstances:
• Vertical terminating exhaust vent installations.
• Horizontal terminating exhaust vent installations greater than 6 feet
(1.8 m) linear measurement, (NOT total equivalent length).
• Vent installations where any section of the exhaust vent pipe passes
through an unconditioned space.
Note: An external condensate drain is recommended in all installations
as best practice in order to maximize the longevity of the Water Heater.
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, except with
the Common Vent System where the provided air intake grill cap is used.
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 2" diameter venting.
Refer to table 9 if using 3" diameter venting.
Refer to table 10 if using 4" diameter venting.
2" Venting Maximum
allowable
Exhaust pipe
length
Twin pipe with 9.5ft
two terminations
Table 8 Maximum Allowable Exhaust and Combustion Air Lengths for 2"
PVC venting
1) If using 90° short sweep elbow.
2) If using 90° long sweep elbow.
Greentherm
Approved terminals
"T" terminal
90° elbow
3" diameter only
"T" terminal
90° elbow
Elbow Equivalency
Combustion
air pipe
length 90°
1) 2)
9.5ft 5 ft /2.5 ft 2.5 ft
3" Venting
Twin pipe with two
terminations
Twin pipe with
concentric
termination
Table 9 Maximum Allowable Exhaust and Combustion Air Lengths for 3"
PP, PVC, CPVC, and ABS venting
Maximum
4" Venting allowable
Exhaust pipe
Twin pipe
Concentric
Table 10 Maximum Allowable Exhaust and Combustion Air Lengths for
4" PP, PVC, CPVC, and ABS 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:
Max. number of 90° elbows
Twin pipe with two terminations 1
Twin pipe with concentric
termination
Table 11
1) If using 90° short sweep elbow.
2) If using 90 ° long sweep elbow.
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 11 above.
Calculation example for 3" PVC, CPVC, or ABS venting:
Exhaust
System used
Number of 90° elbows needed:
Number of 45° elbows needed:
Table 12
45°
Calculation of example
Max. length
90° elbow reduction
sub-total =
45° elbow reduction
Total =
Table 13
Installation instructions | 13
Maximum
allowable
Exhaust pipe Combustion air
length pipe length
31ft 31ft
23ft 23ft
Combustion air
length pipe length
63ft 63ft
43ft 43ft
2" venting 3" venting 4" venting
1) 2)
or 2
_
Twin pipe with concentric
termination
6 720 805 440 (2014/11)
Elbow
Equivalency
90° 45°
5 ft 3 ft
5 ft 3 ft
Elbow
Equivalency
90° 45°
2.5ft 1.5ft
2.5ft 1.5ft
5 7
4 7
1
2
23'
- 5'
18'
- 6'
12'