Product Manual

4-7
Water Leak
Maximum leak noises
Rapid attenuation
of noises
Figure 4-7 Water Leak Pinpointing
To find this spot, the LD-12 user must carefully mark the location of the water line
on the street after locating it exactly with a pipe and cable locator. Usually, the pip-
ing between the valve or hydrant with the loudest sound and the valve or hydrant
with the second loudest sound is the section of the line that needs to be marked. The
section must be accurately located and marked on the street in order for the LD-12
user to consistently listen directly over the line.
The LD-12 user listens with the 3-pronged base attached to the ground microphone
directly over the line. The LD-12 user moves the ground microphone 3 to 4 feet
each time in the direction of the water line, listening and moving closer to the water
leak. While the LD-12 user is moving, he does not adjust the volume control, since
the volume must be held constant in order to make accurate comparisons. When the
LD-12 user is very close to the leak, it may be impossible to decide based upon the
user’s hearing alone whether the leak is in one spot or is in a spot 3 to 4 feet away.
When this occurs, the LD-12 user must study the LD-12 meter display. Usually, the
meter’s needle will be just slightly higher at one spot than at the other. This is the
most important purpose of the meter display, allowing the LD-12 user to accurately
pinpoint the leak’s location when the user’s hearing can not.