Water Hammer – Noisy Water Pipes

Water Hammer.

Water hammer has to be one of the most common complaints we deal with on a day to day basis. So what exactly is water hammer? Well, it can take many forms and shows itself in many different ways. The exact definition is a pressure surge or wave resulting when a fluid (usually a liquid but sometimes also a gas) in motion is forced to stop or change direction suddenly (momentum change). This annoying water pipe noise commonly occurs when a valve is closed suddenly at an end of a pipeline system, and a pressure wave propagates in the pipe. It may also be known as hydraulic shock.

This pressure wave can cause major problems, from noise and vibration to pipe collapse. It is possible to reduce the effects of the water hammer pulses with accumulators and other features.

This common water pipe noise has to be one of the most incorrectly treated plumbing problems amongst Sydney plumbers. The first thing we recommend is to make sure your property is not running water pressure above 500kpa. This may require a pressure regulating valve be fitted to the mains water inlet on your property. Most hot water heater manufactures will insist on water pressure being limited to 500kpa to have warranties honoured.

Some plumbers can over complicate the treatment of this problem. What we find is that 95% of water hammer is situational, ie; a set of taps needs servicing as the lubrication in the spindles and O ring has failed, causing the valve to jump and creating the pipe noise when the tap is turned on or off. The solution is easy – either service or replace the taps in question. Inlet valves in cisterns are another culprit, once a toilet is at the later stages of refilling faulty inlet valves can bounce and cause this problem.

The other big cause of water hammer are appliances that have an instant shut off via an internal solenoid, like a dish washer or a washing machine where the machine takes the required water needed for the cycle and shuts off when it has taken the water it needs. Situational hammer arrestors can absorb this shock. They can be easily installed between the isolation taps and the hose connections. We find using quarter turn washer- less isolator taps takes the moveable washer out of the equation greatly reducing your noisy pipe problem.

So there’s a very brief insight into this very common problem in your house or unit. Do not ignore the noises; it can become problematic when it causes pipe joints to crack. Contact Highlander Plumbing at the first sound of banging pipes, knocking pipes, taps that seem to vibrate; all of these are early signs of water hammer.