A ‘humming’ sound coming from a water pipe is often a good indication of water loss occurring somewhere along the piping system. This can occur in two ways: Loss through a fixture or outlet (i.e. faucet or leaky toilet) or loss through an actual leakage point along the line. It is pretty easy to understand the way a running fixture makes noise on pipes. Water flows at a rapid rate through the line and causes the pipe to vibrate as the water leaves the outlet. Also, friction created by the water flow against the inside of the pipe sends vibrations that can be detected by the human ear. The sound created by a leak in the pipe itself is a little more complex to understand. Essentially, the humming sound created by a leak in the pipe is driven by a pressure difference between the water inside the pipe and the ambient atmospheric pressure around the pipe. When a leak develops in a pipe, a pressure loss occurs in the pipe at the leak site as the pressure in the pipe tries to equalize with the pressure outside the pipe.

This pressure loss creates pressure waves that travel in both directions down the pipe and away from the leak. We call this ‘leak energy.’ In most cases, the human ear alone cannot hear this leak energy. It takes electronic leak detection tools that amplify selected sounds. If you can hear the leak energy without equipment, there is a good chance the leak is close by or has developed in size enough to be quite loud.hvac hydronic fan coil unit If the humming sound you hear is not from flow or a leak in the pipe, a contact point between the pipe and a vibrating appliance or machine such as a refrigerator or air conditioning unit could also cause it.car ac repair kyle tx In any of the cases mentioned above, you can save some time and money by taking a look around your home for some obvious clues. auto repair in yuma az

Double-check all of your interior faucets and toilets. Check outside hose bibs and valves, too. If you don’t find anything, you may need to call a leak detection specialist to perform further investigation with specialized electronic equipment and professional experience. Find service near you Tags: humming sound, leak in sink, leaking pipe, plumbing leak, tips, water leak This entry was posted on at 8:10 am by and is filed under plumbing, tips. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response. Why do Some AC Adapters and Power Supplies Make a Whining Noise? Most of the time our AC adapters and power supplies tend to be quiet, but what does it mean when one makes a whining noise? Should you be concerned? Today’s SuperUser Q&A post has the answers to a worried reader’s questions. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

Photo courtesy of Bart Everson (Flickr). SuperUser reader Rishat Muhametshin wants to know why some of his AC adapters and power supplies make a whining noise: I have many different AC adapters and power supplies for a variety of devices, ranging from small 5V/1A USB chargers to laptop power adapters and desktop PSUs. However, I often hear a whining noise from some of these power supplies. This happens most often when they are not connected to a device or otherwise in use, and stop making noise when I connect a device that is not fully charged. Why do some AC adapters and power supplies make this whining noise? Why do some not make this noise? Is there anything that I can do to suppress it? Why do some AC adapters and power supplies make a whining noise? SuperUser contributors DragonLord and Daniel R Hicks have the answer for us. Most power conversion devices contains coils, such as transformers or inductors. These components use electromagnetism to convert AC main power to low-voltage DC power.

The varying magnetic fields generated by these components can cause them to physically vibrate at high frequency, resulting in a high-pitched noise. Most modern AC adapters are switched-mode power supplies. The internal switching frequency of an SMPS is typically low when unloaded and increases with a load (up to a certain point depending on the design). The no-load frequency is often low enough to be within the human hearing range. In addition, in low or no-load situations the PWM (Pulse Width Modulation) used to regulate voltage at the inverter stage will be at a low duty cycle and create a “spikey” output profile which is more prone to causing vibration in coils, and the transformer itself will tend to vibrate as well. Together, these can lead to audible noise especially in cheaper units which fail to suppress this noise. Under a load, a properly functioning SMPS should operate at a frequency well above the human hearing range, typically 50 KHz or higher (although some older designs operate at 33 kHz).

However, the same noise can occur under a load with a poorly designed or defective power supply as the coils may vibrate under electrical stress at a sub-harmonic frequency. This is why you sometimes see a “glue” of sorts on coils inside electronic devices. The glue helps reduce the vibration and noise the coils generate during normal operation. Of course, this means that a user can apply glue onto coils using a glue gun to suppress coil whine—and yes, people have done this successfully with PC motherboards, graphics cards, and power supplies. However, you generally cannot do this easily on small wall chargers of the sort you mentioned without risking damage to the charger or exposure to potentially dangerous voltages. In conclusion, a whining noise is not necessarily a sign of trouble in cheaper wall chargers when they are unloaded. However, a computer PSU or laptop charger that generates coil noise, especially when under a load, may be defective and you may want to consider replacing it.