Baxi Duo-tec Combi HE LPG Installation & Servicing Instructions Manual page 25

10
8
6
4
2
0
0 2 3 4 5 6
1
Concentric 60/100 Flue (metres) Y
Example 1
Flue Lengths - Not Permissible
10
8
6
4
2
0
0
1
Example 3
Flue Lengths - OK
60Ø Exhaust
Y
Concentric 60/100 Flue
Fig. 17
Additional Accessories
93° Elbow
45° Elbow (Pair)
1 metre 60Ø Extension
© Baxi Heating UK Ltd 2008
10
8
6
4
2
0
0 2
7 8 9 1
Concentric 60/100 Flue (metres) Y
Example 2
Flue Lengths - OK
2 3 4 5 6
Concentric 60/100 Flue (metres) Y
X
45° Elbow
93° Elbow
Concentric Flue
5121369
5121370 Fig. 18
5121368
In the graph the solid line diagonal represents the
relationship between the concentric flue assembly (and any
extensions) and the 60Ø exhaust (and any extensions or
additional bends).
Example 1 - Not Permissible
If, for instance, a concentric length of 6 metres was required
3 4 5 6 7 8 9
and the 60Ø exhaust needed to be 4 metres the graph
shows that this combination would NOT be permissible as
the intersection point would be above the solid diagonal line.
Example 2 - Flue Lengths OK
Where both lengths have been determined they can be
applied to the graph to check that the installation is
permissible. For example, if it was known that 2 metres of
concentric flue and 5 metres of 60Ø exhaust were required,
the values could be applied to the graph as shown in
Example 2. As the point of intersection of the dotted lines is
below the solid diagonal line, the combination of lengths is
shown to be acceptable.
Example 3 - Flue Lengths OK
In the example shown, assume that the concentric part of
the flue needs to be 6 metres long. Find the position of '6' on
the horizontal axis of the graph and then project upwards to
the solid diagonal line. This is represented by the vertical
7 8 9
thick dotted line. Where this dotted line intersects with the
solid diagonal line on the graph, project across to the vertical
axis. As can be seen this corresponds with 2.5 metres.
Therefore, the total equivalent length of the 60Ø exhaust
can be up to 2.5 metres. Any elbow equivalencies must be
accounted for i.e. 93° elbows are equal to 1 metre, each 45°
elbow to 0.5 metres.
Support
Bracket
1 metre Extension
1 metre supplied in kit
9.0 Plume Displacement
9.2 Determining Permissible Lengths
Flue Length - Worked Example
In Fig. 18 opposite an additional 93° elbow and pair of 45°
elbows have been included in the 60Ø exhaust.
Also 3 straight extension pieces have been used.
To calculate total length:-
Length of 60Ø supplied in kit =
3 x 1 metre Extensions =
1 x 93° Elbow =
2 x 45° Elbow =
Total 60Ø =
After consulting the table in Example 3 it can be determined
that the concentric flue could be up to 2.5 metres long.
1 metre
3 metres
1 metre
1 metre (0.5 metres each)
6 metres
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