Main Heating Main Heat 12, Инструкция по установке и обслуживанию

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Fig. C
page 27
9.2 Determining Permissible Lengths - P.D.K.
In the graph the solid line diagonal represents the relationship between the concentric flue assembly (and any extensions) and the 70Ø exhaust (and any
extensions or additional bends).
Example 1 - Not Permissible
If, for instance, a concentric length of 3.25 metres was required and the 70Ø exhaust needed to be 10 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 O K
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 4 metres of 70Ø 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 2 metres long. Find the position of '2' 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 axis. As can be seen this corresponds with 14 metres. Therefore, the total equivalent length of the 70Ø
exhaust can be up to 14 metres. Any elbow equivalencies must be accounted for i.e. 93° elbows are equal to 1 metre, each 45° elbow to 0.5 metres.