Popping Noise in Copper Plumbing

Preventing Water Hammer

Water hammer occurs because water is stopping or starting very suddenly, creating a shock wave that flows through the copper. Plumbing that is installed correctly includes air chambers that compress when the shock wave travels through it. These chambers are built into fittings known as water hammer arrestors. These devices install midway through a pipe or near the end of the pipe and collect all of the shock from the pressure.

Normally, arrestors are designed to drain the liquid out of the air chamber after each shock wave. Once the chamber is drained, it fills with air and is ready for the next shock wave. Air chambers, or water hammer arrestors, can fail over time if they fail to properly drain. If a chamber fails to drain, you may need to drain the main supply lines to restore the functionality of the arrestor. This can be done at the lowest point in the copper piping, usually where a drain cap is located. Removing the cap and allowing the system to drain for several minutes provides enough air in the pipes to restore the arrestor.

Air chambers can fail because of mineral buildup in the pipes. Minerals cling to the walls of pipes and slowly build up over time. Because air chambers are installed along the pipe, they are susceptible to mineral buildup. It's important to clean the filter on the arrestor every year to prevent buildup. Shut off the main water line, remove the arrestor from the fitting and clean the screen using a nylon brush to remove scale and buildup.

Water hammer is capable of wearing down copper pipes over time. The constant banging action inside the pipes can cause pipes to burst or crack. Fittings can become dislodged inside copper pipes as the solder and flux used to connect fittings slowly is separated. This is especially dangerous for copper pipes installed inside of walls, as they are not easily accessible for maintenance or replacement. In the long run, installing a hammer arrestor saves you time and money.