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  • Pressure Vessels (Expansion Vessels) in various sizes from 300ml to 50L, Horizontal or Vertical.

Pressure Vessel


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Product Description

Water Expansion Vessels - Various Sizes

Also known as such as expansion vessels, pressure accumulators and surge arrestors.

A pressure vessel prolongs the life of your pump by providing a reserve of pressurised water to your system. It therefore limits the number of starts of and wear on the pump when it is used for quick short periods of time. For example, if someone were to wash their hands, water would initially come from that stored inside the pressure tank, if the tap was then closed, the pressure vessel would automatically refill from the mains pressure without the need for the pump. The pump would only need to kick in once the pressurised water from the tank has been used ie. if you were to fill a bath or use the shower.

How to get rid of Water Hammer

Water hammer, also known as "Surge Flow", is a specific plumbing noise, not a generic name for pipe clatter. It occurs when the flowrate of fluid in the pipe changes rapidly (for example when a tap or valve is closed too quickly). This creates an hydraulic shock wave back to the pump.  

The shock wave can cause very high pressures in pipes and therefore it can cause burst pipes, damaged supports, leakage at joints. The pressure wave can even travel through pumps, damaging the impellor and drive.

Pressure vessels protect your pump from Water Hammer by absorbing these kind of shocks to the system. Pressure vessels have within them a rubber membrane that creates an air pocket. When the pump/tap is stopped, the water maintains a certain amount of momentum, which can damage both pipes and pumps. By having a compressible void, the water can fill the vessel and use the air void as a shock absorber, reducing the chances of the system being damaged.

Install a Pressure Vessel between the pump and the water outlets according to the pump manufacturer's instructions.


Expansion tanks have a warranty of 2 (two) years against defects of material and workmanship beginning from the date of delivery when correctly installed.

Technical Information

  • Connection: male thread
  • Material: steel
  • Surface treatment: powder coating
  • Colour: red, except 0.3L: Black
  • Flange material: steel galvanised
  • Approval: WRAS (8L vessel only)
  • Content: 0.3l Vertical, 8 ltr Vertical, 24L Horizontal, 50L Horizontal
  • Size: 1", except 0.3L: 1/2"
  • Pressure: 10 bar


300ml Pressure Vessel (Vertical)

  • Diameter: 100 mm
  • Height: 90 mm

8 Litre Pressure Vessel (Vertical)

  • Diameter: 220 mm
  • Height: 380 mm

 24 Litre Pressure Vessel (Horizontal)

  • Diameter: 280 mm
  • Height: 470 mm

50 Litre Pressure Vessel (Horizontal)

  • Diameter: 409 mm
  • Height: 480 mm

Useful Information

How to improve water pump efficiency (and save money) - 5 top tips blog post.

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