Atag Q 25S - Dimensions of the Flue Gas and Air Intake Duct

Installation & Servicing Instructions ATAG Q-Series
20
6.7.1 Dimensioning of the ue gas and air intake duct
The ue diameter is determined by the total length of the run, including for the
connection pipe, elbows ttings and terminal covers etc and the type and number of
boilers installed into the system.
An undersized ue pipe can lead to disorders. Look at table 1 for the choice of the
system and the correct diameter. The table below shows the maximum ue lengths
with the different boiler outputs. A longer ue gas length can be achieved by increasing
the diameter to ø 100mm.
Explanation table 1:
Two pipe ue gas system: maximum noted length = distance between boiler and
roof terminal A
Concentric ue gas system: maximum noted length = distance between boiler and
roof terminal B
When using bends the noted value behind every bend should be deducted from the
maximum straight length.
Pipes with 60/100 diameter are only permitted on wall terminals in
combination with ATAG boilers untill 25kW.
ø80mm
A
in m
ø100mm
A
in m
16-25 kW Maximum straight lenth 80 31 Maximum straight lenth 100 40
87° bend resistance length -1,5 87° bend resistance length -1,8
45° bend resistance length -0,8 45° bend resistance length -0,9
26-38 kW Maximum straight lenth 80 18 Maximum straight lenth 100 39
87° bend resistance length -1,5 87° bend resistance length -1,8
45° bend resistance length -0,8 45° bend resistance length -0,9
39-60 kW Maximum straight lenth 80 6 Maximum straight lenth 100 18
87° bend resistance length -1,5 87° bend resistance length -1,8
45° bend resistance length -0,8 45° bend resistance length -0,9
ø60/100mm
B
in m
ø80/125mm
B
in m
ø100/150mm
B
in m
16-25 kW Maximum straight lenth 60/100 12 Maximum straight lenth 80/125 31 Maximum straight lenth 100/150 40
87° bend resistance length -1 87° bend resistance length -2,8 87° bend resistance length -2,6
45° bend resistance length -1 45° bend resistance length -1,1 45° bend resistance length -1,1
26-38 kW Maximum straight lenth 80/125 13 Maximum straight lenth 100/150 34
87° bend resistance length -2,8 87° bend resistance length -2,6
45° bend resistance length -1,1 45° bend resistance length -1,1
39-60 kW Maximum straight lenth 80/125 6 Maximum straight lenth 100/150 10
87° bend resistance length -2,8 87° bend resistance length -2,6
45° bend resistance length -1,1 45° bend resistance length -1,1
Concentric flue system
Two pipe flue system + chimney lining
Dimensions ue gas system and air supply system Table 5
Example:
A 25kW with a concentric
ue gas system ø80/125mm
has according to the table a
maximum ue straight length
of 31m In the system that is
going to be put in there are 2
x 45° bends, so the maximum
ue gas length is
31 – ( 2 x 1.1 ) = 28.8 meters.