How To

How to survey and pinpoint with the DNR-18

1. The sounds of leaks in pressurized water pipes can travel for hundreds of meter in every direction down the mains and services. If there is no evidence of the leak, then compare the loudness of the leak sounds at the meters, valves, and hydrants.

Leak sounds travel on pipes.

Leak surveying by listening at a meter with contact rod.

2. With the long metal rod for sensor, attach the tip of rod to each meter or each valve.
Then, save the minimum level value with file number and date/hour. (001 to 250 can be saved). Repeat that for all the locations checked. The Minimum level value expresses the continuous leak noise level picked up with sensor during the sound hearing.

The Saved data file is indicated on LCD by the graphical display. (001 to 250 values can be saved). The higher Minimum Level Value is the closer to the leak. Please check the consumption noise when you survey the leak noise with the meter whether or not the consumer is using the water in the house so that you are not confused by the consumption noise. Please pay attention to the consumption noise which is almost same as the leak noise.

3.Saved readings can be downloaded to a PC and details such as geographical location, the graph of readings etc.

After the leak surveying at valves and meters, you found fourth (4) and fifth (5) points are loudest leak sounds as the above graph. Now you are ready to begin the "Pinpointing".

Sound levels taken at different meters and valves can be saved up to 250.


A "Bar Display" gives a visual indication of the sound level.

4 First, mark the exact location of the pipe between the two loudest Meters with a pipe locator. Then listen and save the leak loudness level every 40-50cm directly over the pipe.
Sound levels taken at different positions along the pipe run, can be saved. The saved results for one survey can then be displayed in graph from indicating the point of maximum leak sound and the position of the leak.

The "Saved" data file showing 10 leak sound levels and graphical display. Leak is at the peak sound level in the center. Let the DNR-18's amplifier pinpoint the leak's location for you instead of relying upon your hearing.

The peak is indicating the point of maximum leak sound and the position of the leak.

Confirmation does save you time and money.

6. There is a case that the loudest point which is not right above the point of water leak, depending on conditions in the ground and the road surface.
After marking the leaking point on the ground make a hole at the marked point by use of the Electric Hammer Drill and Boring bar and then, insert the Listening Stick in to the hole so as to final Pinpointing.

Using the Noise Reduction feature of the DNR-18

The DNR-18 has frequency filters for some of continuous noise from A/C hum, motors, but has an additional Noise Reduction feature which reduces the effect of transient noises.
The NR system, This system removes transient and fluctuating or varying noise and delivers only the "constant" noise caused by leak.
The NR level imposes a delay between the time when the push button is pressed and the sound is heard.
Lv.1: 0.2 seconds
Lv.2: 1.0 seconds
Lv.3: 3.0 seconds
Increasing the Noise Reduction Level increases the effect of this feature.
At all times when the push button is pressed the "Minimum" (MIN 000 to 999)value is the level of the constant noise.
NOTE: The pick-up sensor must be in contact with the ground when the push button is pressed in the NR mode. Failure to ensure this will give incorrect results.

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