Wolf CGB-2 Series Installation Instructions For Contractors page 74

Connection to the balanced flue
Calculating the
balanced flue length
Minimum duct size for room sealed operation C93x
Assuming: In the installation room:
2x inspection bends, 1x 87° bend and
1.5 m horizontal with 87° support bend
C93x
74
37. Technical information, air/flue gas
routing
If the gas condensing boiler is installed with a balanced flue routed over an external wall
(type C13x), the rated boiler output in heating mode must be reduced to below 11 kW
(for appropriate measures, see chapter "Limiting the maximum output").
It must be possible to inspect the entire cross-section of the flues. Therefore, install an
appropriate cleaning and/or inspection aperture inside the boiler room; agree suitable
arrangements with your local flue gas inspector.
Flue connections are created using couplings and gaskets. Always arrange couplings
against the direction of the condensate flow. Install the balanced flue with a slope
of at least 3° towards the gas condensing boiler. Install spacer clamps to secure
the positioning (see installation examples).
The calculated length of the balanced flue system or the flue is derived from the straight
pipe length and the length of any pipe bends.
Example for a 60/100 system
Straight balanced flue pipe, length 1.5 m
1 x 87° bend ≙ 1.5 m
2 x 45° bends ≙ 2 x 1.3 m
Note: To avoid reciprocal interference between air and flue gas pipes routed above
the roof, we recommend maintaining a minimum clearance of 2.5 m between
the pipes.
Equivalent length of the system:
1)
Flue pipe DN 80
20
19
18
17
16
15
14
13
12
11
10
9
8
Flue pipe DN 80
20
19
18
17
16
15
14
13
12
11
10
Flue pipe DN 60
1) :
L = straight length + bend length
L = 1.5 m + 1 x 1.5 m + 2 x 1.3 m
L = 5.6 m
87° bend
45° bend
100 110 120 130
Square duct [mm]
9
8
110 120 130
Round duct [mm]
Connecting pipe
DN 60/100
square
Connecting pipe
DN 60/100
round
Duct cross-section in [mm]
60/100 80/125
1.5 m 3 m
1.3 m 1.5 m
Connecting pipe
DN 80/125
Connecting pipe
DN 60/100
a
a
140 150 160
Connecting pipe
DN 80/125
Connecting pipe
DN 60/100
Ø
140 150 160
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