Wolf CGB-75 Assembly And Operating Instructions Manual page 44

Flue gas temperature limiter
The electronic flue gas temperature limiter switches the oil
condensing boiler off when the flue gas temperature exceeds
110 °C.
The boiler restarts when the reset button is pressed.
Connection to the balanced flue
The unobstructed cross-section of flues must be able to be
inspected. Therefore, install an inspection and/or test 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.
The balanced flue should be installed with
a slope of at least 3° (6 cm/m) to the gas
condensing boiler. Install spacer clamps to
secure the location (see installation example).
In the worst case scenario, a lesser slope of
the balanced flue may lead to corrosion or
operating faults.
Generally bevel or deburr trimmed flues to
NB
ensure a gas tight installation of pipe joints.
Ensure that gaskets are correctly fitted. Remove
all contamination prior to installation - never fit
faulty parts.
Between the flue terminal and the roof surface, as of a rated
output of 50 kW, there must be a clearance of at least 1.0 m.
44
Design information
Calculating the balanced flue length
The calculated length of the balanced flue system or
the flue is derived from the straight pipe length and the
length of the pipe bends. In this calculation, a 90° bend
or a 87° tee is calculated as being 2 m and a 45° bend as
being 1 m.
Example:
Length of straight balanced flue 1.5 m
Inspection tee 87° = 2 m
2 x 45° bends = 2 x 1 m
L = 1.5 m + 1 x 2 m + 2 x 1 m
L = 5.5 m
Table: Pipe length calculation
Component
87° bend
45° bend
Tee 87° with
inspection aperture
Straight pipe
Calculated length
2 m
1 m
2 m
Subject to length
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