Heath Consultants Aqua-Scop - Manual (Page 25)

At point 7 there is no curb valve present nor is there any accessible
contact point on the service to the house. Therefore, a direct contact
inside the house is necessary. At hydrant 8 the noise is also very much
smaller. This acoustical preliminary detection can be accomplished
with far more ease by using the meter on the optional Meter Readout
Module. At this time by listening to the loudest noise that has been
detected, a medium reading of the scale is to be set. In this example,
at measurement point 5, a reading of .60 units is set on the scale by
turning the Meter Readout Control Knob clockwise while a test is being
taken. This setting is recommended to be able to see an increase or a
decrease of the reading on the instrument at the different test points. For
all further comparative measurements, the setting of intensity of sound
and meter are not to be changed, as any change during comparisons will
affect the uniformity of the test. If a change in setting is necessary, all
comparative tests must be repeated at the new setting. Meter reading
at point 4 gives a decrease of reading down to .15 units, which would
substantiate the acoustical result. On the other hand, the meter reading
at point 6 shows an increase to nearly .70 units. This indicates further
search towards point 7 is necessary. The test in house 7 is conducted
with an unchanged setting of the instrument. It gives another decrease
in instrument reading of .30 units. But we are to keep in mind that the
length of the service (the test was taken in the house) might influence
the result of the test. The final measurement at hydrant 8 is less than .10
units. Following this preliminary detection, the leakage should be near
point 6. Pinpointing is now conducted with the Ground Microphone.
C. Pinpointing With The Ground Microphone
The Ground Microphone is exchanged for the Direct Contact
Microphone. The “Listen” Control switch at the upper left of the
instrument is the interface between the Microphone and the Amplifier
and should only be depressed when the Ground Microphone is placed
in a test position. In working with the Ground Microphone, use a setting
of 4 to 6 units of amplification. Using higher sensitivity by opening
the sensitivity (volume) control will also give an amplification of
background noises.
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