What is the Purpose of a Water Hammer Arrestor?

What is Water Hammer?

A water hammer is a phenomenon that occurs when water flowing in a pipe suddenly stops or changes direction due to a fast-closing valve, such as a faucet, a dishwasher, or a washing machine. This causes a pressure surge or shock wave that travels back and forth in the pipe, creating a loud banging or clanging noise. Water hammer can also damage pipes, fittings, valves, and appliances by causing leaks, cracks, or bursts.

What is The Purpose of Water Hammer Arrestor?

The purpose of a water hammer arrestor is to prevent or reduce water hammer by absorbing the pressure surge with a cushion of air. It consists of a chamber filled with air or gas that is separated from the water by a piston or a diaphragm. When a valve closes quickly and stops the water flow, the piston or diaphragm moves up and compresses the air or gas in the chamber, thereby absorbing the shock wave. When the pressure returns to normal, the piston or diaphragm moves back to its original position, ready for the next surge.

What are the Types of Water Hammer Arrestors?

There are different types of water hammer arrestors available for different applications and pipe sizes. Some of the common types are:

• Screw-on arrestors: These are easy to install and can be attached to faucets, dishwashers, washing machines, and other appliances with screw-on connections. They are usually designed for residential use and have small pipe diameters.
• Tee arrestors: These are installed by cutting the pipe and adding a tee fitting. They can be used for larger pipe diameters and commercial applications. They are more durable and effective than screw-on arrestors.
• In-line arrestors: These are installed by cutting the pipe and inserting the arrestor between two couplings. They can be used for any pipe diameter and application. They are similar to tee arrestors but have a more compact design.

How to Install a Water Hammer Arrestor?

The installation of a water hammer arrestor depends on the type and location of the device. However, some general steps are:

• Identify the source of the water hammer by turning on and off different valves and appliances until you hear the noise.
• Choose an appropriate type and size of water hammer arrestor for your pipe and application.
• Turn off the water supply and drain the pipes before cutting or attaching anything.
• Follow the manufacturer’s instructions for installing the water hammer arrestor. Make sure it is securely attached and oriented correctly.
• Turn on the water supply and test the valve or appliance that caused the water hammer. Check for leaks and noise reduction.

What are the Benefits of a Water Hammer Arrestor?

A water hammer arrestor can provide several benefits, such as:

• Eliminating or reducing annoying and potentially damaging noise caused by water hammer.
• Protecting pipes, fittings, valves, and appliances from leaks, cracks, or bursts due to water hammer.
• Extending the lifespan and performance of plumbing systems and appliances by preventing water hammer.
• Saving money on repairs and replacements of damaged plumbing components due to water hammer.

Common FAQ

Are water hammer arrestors necessary?

The answer to your question depends on the type of appliance and pipe you have. According to some sources, a general plumbing rule is that water hammer arrestors are needed on appliances that have quick-closing valves such as solenoid valves. These include dishwashers, washing machines, water dispensers, and refrigerator icemakers. However, other sources suggest that you may not need water hammer arrestors if you have PEX pipes, which are flexible plastic pipes that can absorb some of the pressure surges. Therefore, you should consult your plumber or manufacturer for the best advice on whether you need a water hammer arrestor for your specific situation.

Where should a water hammer arrestor be placed?

To prevent sudden pressure changes that can cause jarring banging noises in your plumbing system, it’s important to install appropriately sized water hammer arrestors on the hot and cold water supply piping for any fixtures, equipment, or apparatus where shock may occur. Additionally, installing a pressure-reducing valve on the discharge side of your water meter can be highly beneficial in protecting your home’s piping system.

Do water hammer arrestors really work?

Installing a water hammer arrestor correctly can effectively eliminate any shock and noise that may be produced from your piping. In residential plumbing systems, the occurrence of severe shock is common when there is excessive water pressure. By installing water hammer arrestors properly, you can reduce the likelihood of damaging your plumbing system.

What happens if you ignore water hammer?

Water hammer may seem harmless at first glance and sound, but neglecting it can lead to significant damage to your plumbing system over time.

Conclusion

The purpose of water hammer arrestor is to prevent or reduce water hammer by absorbing the pressure surge with a cushion of air. It can protect your plumbing system and appliances from damage and noise caused by water hammers. It can also save you money on repairs and replacements of damaged plumbing components due to water hammer. Therefore, it is advisable to install a water hammer arrestor if you experience a water hammer in your pipes.