Key Features

• Usage: Prevents water hammer
• Usage: Reduces over pressure in hot and cold sanitary water circuits

What's Included

• Absorber shock inline
• AD HDU shock arrester
• Seal-bonded seal
• Carton
• Label
• Mini grip bag

Use the Worcester Bosch 4 Flow 8000 D Water Arrestor Hammer to absorb shocks that are caused by sudden water pressure changes. This device is installed between a water supply line and a shut-off valve to avoid loud banging noises and damage to pipes, pressure sensors or flow metres. A water arrestor hammer acts like an air chamber to provide pressurised water a space to flow rather than the water getting blocked into a closed valve, creating a noise.

What is water hammer?

Water hammer is the noise your pipes create when moving water inside of them reaches a sudden stop, causing the entire pipework system to shake and rattle. The sudden stop is caused when you switch off the water (usually by turning off a tap), though the water expects to continue flowing and slams into the end pathway in a pipework system.

When this problem first arises, it's essentially more of an annoyance than a danger. But hearing continuous shocks and vibrations in your pipework can not only become a nuisance for you and neighbours, but these movements can weaken the pipework system, making it more prone to cracks and holes in the future.

The common causes of water hammer

There are many reasons why water hammer might occur, such as having old pipes, so the changes in water pressure causes loose pipes to wiggle and move around. High water pressure is another culprit, and when water pressure is higher than around 80 psi, installing a pressure regulator can help to prevent sudden water stoppage. Another reason could be that there's water in air chambers, which builds up pressure, causing water to suddenly stop when you switch of a water appliance.

How often to change a water arrestor hammer

Thankfully, you won't need to update a water arrestor hammer often — around every 5 to 25 years will suffice, depending on water and pipework quality, and the plumbing system's pressure.