Bosch 940 ES Installation Manual page 12

Installation instructions
Calculation example for 3" venting:
Exhaust
System used
Number of 90° elbows needed:
Number of 45° elbows needed:
Table 8
Calculation of example
Max. length
90° elbow reduction
sub-total =
45° elbow reduction
Table 9
For this example, the maximum allowable
i
exhaust pipe length is 23.5 feet.
Combustion air
System used
Number of 90° elbows needed:
Number of 45° elbows needed:
Table 10
Calculation of example
Max. length
90° elbow reduction
sub-total =
45° elbow reduction
Table 11
For this example, the maximum allowable
i
combustion air pipe length is 22.25 feet.
12
Concentric
1
2
28.5'
- 2.5'
26'
- 2.5'
Total = 23.5'
Concentric
2
1
28.5'
- 5'
23.5'
- 1.25'
Total = 22.25'
Calculation example for 4" venting:
Exhaust
System used
Number of 90° elbows needed:
Number of 45° elbows needed:
Table 12
Calculation of example
Max. length
90° elbow reduction
sub-total =
45° elbow reduction
Table 13
For this example, the maximum allowable
i
exhaust pipe length is 57.25 feet.
Combustion air
System used
Number of 90° elbows needed:
Number of 45° elbows needed:
Table 14
Calculation of example
Max. length
90° elbow reduction
sub-total =
45° elbow reduction
Table 15
For this example, the maximum allowable
i
combustion air pipe length is 58.5 feet.
Twin pipe
2
2
61.25'
- 2.5'
58.75'
- 1.5'
Total = 57.25'
Twin pipe
1
2
61.25'
- 1.25'
60'
- 1.5'
Total = 58.5'
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