APG KA Cable Suspended user manual - Manual (Page 13)

Rev. A2, 12/08 KA Series
13
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• Operating Level Adjustment
Switch operating levels depend on the height at which the fl oat is
positioned in the tank by the cable fastening and the distance along the cable
between the fl oat and the weight. The Termination and Height Fixing section
on the next page of this manual discusses the methods for securing the cable
at the required height. The height of the face of the fl oat in the free hanging
position, with no liquid present, is used as a zero reference for adjusting all
switch point operating levels per the graph and diagram below. Level settings
may vary slightly between switches. Final adjustments should be made under
actual pumping conditions. If there is surface wave motion, some variation in
actual switching levels may occur.
For single level types (1L, 1H, 1C, 1LE and 1HE), the fl oat should be hung
so that the desired switching point is 5 inches above the zero reference. This
represents the diff erence in height between levels O and LL. Note that these
single level switches do not require a weight on the cable for their tilting
operation.
For multi level types, the distance A (from zero reference 0 to weight) has
to be adjusted to obtain the desired switching diff erential. For most switches
the diff erential height B between levels H and L is the crucial dimension. The
required value for B, together with the corresponding value of A, is selected
from the graph shown on the next page. Then, if the weight is wedged at
that distance and the fl oat hung in accordance with the diagram, the switch
points will operate with the correct diff erential. The graph gives the distance
C between levels H and HH for the determined value of A. It will be seen that
switching levels HH and LL bear a specifi c relationship to A and B and cannot
be independently adjusted. Thus, if it is essential to be able to adjust these
levels separately, two fl oats may be needed rather than just one.