Potterton Performa 24 Eco HE Installation & Service Instructions Manual page 24

3
2
1
0
0 1 2
Concentric 60/100 Flue (metres) Y
Example 1
Flue Lengths - Not Permissible
3
2
1
0
0
Example 3
Flue Lengths - OK
60Ø Exhaust
Y
Concentric 60/100 Flue
Fig. 17
Additional Accessories
A - 93° Elbow 5117381
B - 45° Elbow (Pair) 5117382
C - 1 metre 60Ø Extension 5117380
24
© Baxi Heating UK Ltd 2009
3
2
1
0
3 0 1
Concentric 60/100 Flue (metres) Y
Example 2
Flue Lengths - OK
1 2
Concentric 60/100 Flue (metres) Y
X
93° Elbow
Fig. 18
9.0 Plume Displacement
9.2
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 2 metres was required
2 3
and the 60Ø exhaust needed to be 1.5 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 1 metre of
concentric flue and 1.5 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 1 metres long. Find the position of '1' on
the horizontal axis of the graph and then project upwards to
the solid diagonal line. This is represented by the vertical
thick dotted line. Where this dotted line intersects with the
solid diagonal line on the graph, project across to the vertical
3
axis. As can be seen this corresponds with 2 metres.
Therefore, the total equivalent length of the 60Ø exhaust
can be up to 2 metres. Any bend equivalencies must be
accounted for i.e. 93° bends are equal to 1 metre, each 45°
bend to 0.5 metres.
Support
Flue Length - Worked Example
Bracket
Potterton Performa 24 Eco HE
In Fig. 18 opposite an additional 93° bend has been included
Extension
in the 60Ø exhaust. with 2 x 1metre extensions which have
been cut to 0.25metres and fitted. The waste is discarded.
Concentric Flue
To calculate total length:-
2 x 0.25 metre Lengths =
1 x 93° Elbow =
Total 60Ø Exhaust =
After consulting the table in Example 3 it can be determined
that the concentric flue could be up to approximately 0.5
metres long.
Determining Permissible Lengths
0.5 metres
1 metre
1.5 metres