Bosch GWH C 800 ES Installation Instructions Manual page 18

Installation instructions
3.12.2 Vent length calculation
Adjusting the minimum power (P2) based on the
total combined vent length.
After installing the GWH C 800 ES, the minimum power
fan speed must be selected to compensate for variation
in vent pipe length.
Fittings or Piping
45 degree elbow
90 degree elbow
plastic pipe per foot
concentric vent kit
Table 6 Friction Loss Equivalent in piping and fittings
Note: See table 4 for maximum vent lengths.
Total vent length calculation
B Determine the total length of all straight sections of
vent pipe and enter in table 7, line 1.
B Count the number of 90° elbows used, multiply by 5,
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, multiply by 3,
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 7.
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 vent length calculated is 19 feet or
less, no P2 adjustment is needed.
18
Equivalent
feet m
3 0.91
5 1.52
1 0.30
3 0.91
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 7 Determining vent length combination (see
example in Table 8)
__ =
____
__ x 5 =
____
__ x 3 =
____
Total:
____
__ x 1 =
____
__ x 5 =
____
__ x 3 =
____
Total:
____
____
6 720 608 643