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.
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.
Leak surveying by listening at a meter with contact rod.
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
Sound levels taken at different meters and valves can be saved up to 250.
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.
A "Bar Display" gives a visual indication of the sound level.
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.
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.
Confirmation does save you time and money.
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
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.