Bosch GWH 715 ES Installation Instructions Manual page 19

3.11.4 Vent length calculation
Adjusting the minimum power (P2) based on the total
combined vent length.
After installing the GWH 715 ES, the minimum power
fan speed must be selected to compensate for variation
in vent pipe length.
Total vent length calculation
B Determine the total length of all straight sections of
vent pipe and enter in table 8, line 1.
B Count the number of 90° elbows used and enter that
value in line 2. (Do not count end terminal and first
elbow after the appliance).
B Count the number of 45° elbows used and enter that
value in line 3.
B Repeat steps 1 through 3 for air intake pipe and enter
those values in the intake section of table 8.
B Add line 4 from Exhaust to line 4 of Intake and enter
result in line 5.
This is the total equivalent vent length.
NOTE: If total equivalent vent length calculated
is 19 feet or less, no P2 adjustment is needed.
Exhaust
1 Straight section length
2 90° elbows (qty)
3 45° elbows (qty)
4
Intake
1 Straight section length
2 90° elbows (qty)
3 45° elbows (qty)
4
5 Total equivalent vent length =
Table 8 Determining vent length combination (see
example in Table 9)
Example
Exhaust
• 7 - 3' straight sections
• 1 - 1' straight section
• 1 - 90° elbow.
Intake
• 5 - 3' straight sections
• 1 - 90° elbows.
6 720 608 158
__ =
____
__ x 2.5 =
____
__ x 1.25 =
____
Total:
____
__ =
____
__ x 2.5 =
____
__ x 1.25 =
____
Total:
____
____
Total length 22'
Total length 15'
Example
Exhaust
Straight section length
90° elbows (qty)
45° elbows (qty)
Intake
Straight section length
90° elbows (qty)
45° elbows (qty)
Total equivalent vent length =
Table 9 Determining vent length combination example
Total maximum length not to exceed 52 ft.
i
Installation instructions
22 = 22
1 x 2.5 = 2.5
0 x 1.25 = 0
Total:
24.5
15 = 15
1 x 2.5 = 2.5
0 x 1.25 = 0
Total: 17.5
42
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