How To Stop Water Hammer Noise With A Water Hammer Arrestor

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Do you ever turn off a water faucet only to hear a momentary bumping noise in the nearby water pipes? If so, the noise might be due to a plumbing problem referred to as water hammer. Homeowners can usually eliminate water hammer noise and protect their water pipes by installing a water hammer arrestor.

The noise from water hammer occurs when the forward momentum of water flowing through a pipe is suddenly stopped. The sudden blockage causes the water pressure inside the incoming water pipe to instantly spike. The noise of water hammer is created by the shock wave that momentarily rebounds within the walls of the pipe.

Water hammer is not just an annoying noise. The pressure variations that accompany water hammer can potentially damage a water pipe. A key aspect of water hammer is that it occurs in response to a sudden stoppage of water flow. As a result, you can perform a simple test that may identify a water pipe noise as water hammer.

Identifying water hammer

Instead of quickly closing an offending faucet, shut off the faucet more slowly. If a gradual reduction in water flow results in no water hammer noise, the incoming water supply line likely needs servicing. Water hammer is a fairly basic problem, and the solutions for solving a water hammer problem require relatively little modification to your water piping.

In addition to faucets, some household appliances can cause water hammer. Washing machines are notorious for causing water hammer, due to their automatic valves that close instantly. Regardless of the water outlet type, a small water hammer arrestor can be installed near each outlet valve that is causing water hammer noises.

Benefits of a water hammer arrestor

A water hammer arrestor is somewhat like a shock absorber for a water supply line. A sealed pocket of air in the water hammer arrestor absorbs the shock of a sudden valve closure. As a result, there is no water hammer noise and your water pipes are not subjected to harmful spikes in pressure.

Types of water hammer arrestors

Some water hammer arrestors contain a piston that retracts in response to a sudden increase in water pressure. Other water hammer arrestors contain an internal diaphragm to absorb a pressure spike. There is no water flow through the water hammer arrestor itself. The sealed water hammer arrestor is simply connected to a single point on the water supply line.

The installation of water hammer arrestors also presents the opportunity to ensure that your water lines have adequate hangers and support brackets. For more information, visit a website such as