Air chambers are an essential part of any plumbing system, as they regulate pressure and prevent water from forming waves in the supply pipes. Installing air chambers at key points in your system can help to eliminate the waves that cause water hammers. Air chambers are small lengths of pipe that are mounted in water pipes, close to a fitting. They are designed to stop hydraulic shock, also known as water hammer. The air in the chamber compresses and absorbs the impact of water that moves sharply in the pipes.
This happens when a device shuts off the water quickly. In the past, water hammer suppressors consisted of air chambers that were a vertically installed, air-filled piece of plugged pipe. The air provides a cushion to absorb the water hammer. Unfortunately, air is water soluble, so over time these air chambers can become flooded as all the air is absorbed by the water. Once flooded, the bladder is no longer an air chamber, but a water chamber and will no longer absorb the pressure of the water hammer.
To fix this issue, you need to remove the plumbing fixture where the water hammer is taking place. Trim the drywall around the water supply valves to access the wall pipes. Loosen the water supply valve coupler with an adjustable wrench, and then slide the valve, ferrule, and coupler out of the copper tubing. Cut an 18-inch copper pipe that matches the diameter of the copper pipe in the wall with a pipe cutter. Clean the burrs on each end of the pipe, and then apply flux to one end of the copper pipe and to the inside of a copper cap of the same diameter as the pipe.
Weld the cap to the pipe with welding wire and a torch. A more modern solution is a water hammer suppressor which works much like an old-style bladder, but includes a chamber filled with air or gas that is sealed by a diaphragm or piston. This type of suppressor is more reliable than traditional air chambers and can help to reduce or eliminate water hammer.