Where Should Water Hammer Arrestors Be Installed

Where Should Water Hammer Arrestors Be Installed? A Comprehensive Guide

Water hammer, that unsettling bang or thump in your pipes, is a serious issue that can lead to costly repairs. Preventing it requires strategic installation of water hammer arrestors. This comprehensive guide explains where these essential devices should be placed to maximize their effectiveness and protect your plumbing system. Understanding the causes and effects of water hammer is key to proper arrestor placement.

Understanding Water Hammer and Its Causes

Water hammer occurs when the rapid deceleration of water flow creates a pressure surge within the pipes. This often happens when a valve suddenly closes, such as a faucet being turned off quickly. The sudden stop of water momentum creates a shockwave that travels through the pipes, leading to the characteristic banging sound. The severity of water hammer depends on several factors, including pipe material, water pressure, and the speed of valve closure.

Ideal Locations for Water Hammer Arrestors

The placement of water hammer arrestors is crucial for their effectiveness. Here's a breakdown of optimal locations:

1. Immediately Downstream of Valves: This is arguably the most critical location. Install arrestors immediately after valves that frequently experience rapid closure, such as:

• Faucet shut-off valves: Install an arrestor on the supply line to each faucet, particularly those used frequently or those with high flow rates.
• Toilet shut-off valves: Toilets are notorious for generating water hammer due to their rapid valve closure.
• Washing machine shut-off valves: The sudden stop of water flow during a washing machine's cycle can create significant water hammer.
• Dishwasher shut-off valves: Similar to washing machines, dishwashers can also contribute to water hammer.
• Main shut-off valves: Consider installing an arrestor after your main shut-off valve as an added layer of protection.

2. At the End of Long Pipe Runs: Water hammer energy can build up and become amplified over long distances. Installing an arrestor at the end of long, straight pipe sections helps dissipate the shockwave before it reaches fittings or appliances.

3. Near Appliances: Protecting vulnerable appliances like washing machines and water heaters is essential. Install arrestors on the supply lines immediately before these appliances to mitigate the risk of damage.

4. Before Pressure Regulators: Pressure regulators can amplify the effects of water hammer, so placing an arrestor upstream can help prevent damage to the regulator and downstream components.

5. On Vertical Pipe Runs: While less common, water hammer can be particularly forceful on vertical pipes. Installing an arrestor at the base of a vertical run can help absorb the shockwave before it travels further.

6. Consider Pipe Material and Diameter: The size and material of your pipes influence the severity of water hammer. Smaller diameter pipes and rigid materials are more susceptible to damage. In these instances, strategic arrestor placement is even more vital.

Types of Water Hammer Arrestors and Selection

Various types of arrestors are available, each with its own advantages and disadvantages. The selection depends on factors such as flow rate, pressure, and application. Common types include:

• Air Chamber Arrestors: These relatively simple and inexpensive devices utilize a trapped air pocket to absorb the shockwave.
• Hydraulic Arrestors: These are more complex and generally more effective than air chambers, offering greater protection against severe water hammer.

Maintenance and Considerations

Regular maintenance is vital for the longevity and effectiveness of water hammer arrestors. Air chambers, for example, may require periodic air replenishment as air can gradually be absorbed over time. Consult a qualified plumber for routine inspections and to address any concerns about water hammer.

By strategically placing water hammer arrestors in the locations mentioned above, you can significantly reduce the risk of damage to your plumbing system and prevent those annoying and potentially damaging bangs. Remember to consult with a professional plumber for advice tailored to your specific plumbing setup.