A.O. Smith BFC Cyclone, Installation, User And Service Manual

Page: 63 / 118

Refer to the table for the correct pipe dimensions of the C13 or a C33 parallel venting
systems.
Description Unit BFC 2 8 - 60
(1)
BFC 80 - 120
(2)
Default
Diameter flue discharge/
air inlet mm 2x100 2x130
Maximum length air inlet m 55 65
Maximum length flue gas
outlet m 55 65
L
equivalent
45°-bend m 1,2 1,4
L
equivalent
90°-bend m 4,6 2,4
Diameter enlargement
Diameter flue discharge/
air inlet mm 2x130 2x150
Maximum length air inlet m 100 100
Maximum length flue gas
outlet m 100 100
L
equivalent
45°-bend m 1,4 1,6
L
equivalent
90°-bend m 2,4 2,6
1 - When the maximum total length for the default diameter of 100 mm is insufficient,
diameter 130 mm should be used. Any diameter enlargement must be carried out on both
air inlet and flue gas outlet.
2 - When the maximum total length for the default diameter of 130 mm is insufficient,
diameter 150 mm should be used. Any diameter enlargement must be carried out on both
air inlet and flue gas outlet.
Caution
Always make sure the installation is in compliance with the requirements stated in this
table.
Caution
Use a run-off of 50 mm per meter towards the water heater.
Calculate the maximum length of the air inlet and the flue gas outlet seperately:
Sum the lengths of the different pipe sections without bends. Ignore the length of
the adaptor box.
Sum the lengths of the bends. Ignore the bend in the adapter box:
Sum L
equivalent
for each 45° bend.
Sum L
equivalent
for each 90° bend.
Sum the lengths of the pipe sections and the lengths of the bends to calculate the
overall length of the air inlet and the flue gas outlet.
Adjust the length of the air inlet and/or the flue gas outlet when the overall length
exceeds the maximum length as stated in the table.
c
1.
2.
-
-
3.
4.
0311704_BFC_28-120_III_ ENEN_V2.4, 2022-10-17 63