Recent changes to building codes allow for an alternative to cold water expansion valves (CWE), utilising an expansion vessel for mains pressure hot water cylinder installations.

The use of an expansion vessel has been used in many countries as a means of allowing for thermal expansion for various reasons. These include the elimination of the CWE relief drain pipework and the prevention of the loss of the expansion water to waste.

For complete details on using an expansion vessel, refer to The NZ Building Code G12 Amendment 13 details an alternative to cold water expansion valves (CWE), utilising an expansion vessel for mains pressure hot water cylinder installations. It is the installer's responsibility to size and install the expansion vessel appropriately.

• Comply with BS EN 13831 and be suitable for use with potable (drinking) water

• Be sized to ensure that the maximum system pressure does not exceed the working pressure of the hot water storage vessel and the working pressure of expansion vessel itself

• Be pre-charged to a pressure matching the water supply pressure to the mains pressure storage water heater

• Be installed with a heat trap on the cold-water supply pipe between the expansion vessel and the storage water heater when the expansion vessel is located within 500mm of a storage water heater inlet

• Be installed in a manner which provides for easy access for replacement, servicing and maintenance

• Be adequately supported or restrained to prevent damage at the point of connection of the vessel to the pipework if the vessel is subject to external forces

The sizing of the expansion vessel is critical to its correct operation.

This table shows the common sizes of hot water cylinders and the thermostat settings. It is provided to assist in the selection of the correct-sized expansion vessel.

Chart sizing based on maximum incoming pressure of 500kPA and the TPR Valve set to 850kPA.

BIA-BPT-60

Bianco Pressure Tank

60 Litre Vertical 

Almond 

4 Bar Pre-Charge

Code: 811173

BIA-BPT-40

Bianco Pressure Tank

40 Litre Vertical 

Almond 

4 Bar Pre-Charge

Code: 811870

BIA-BPT-24

Bianco Pressure Tank

24 Litre Vertical 

Almond 

4 Bar Pre-Charge

Code: 811172

BIA-BPT-18

Bianco Pressure Tank

18 Litre Vertical 

Almond 

4 Bar Pre-Charge

Code: 811171

BIA-BPT-8

Bianco Pressure Tank 

8 Litre Vertical 

Almond 

4 Bar Pre-Charge

Code: 811170

Bianco Pumpz Pressure Tanks, where innovative engineering meets exceptional performance in water management systems.

Bianco Pumpz is a trusted name in the industry, offering a wide range of pressure tanks designed to meet the diverse

needs of residential, commercial, and industrial applications.

The Bianco Pumpz Pressure Tanks are meticulously engineered to provide optimal water pressure, maintain system stability, and ensure a consistent flow of water for various purposes. 

Built with attention to detail, our tanks are crafted from premium materials to ensure long-lasting durability, even in demanding environments. 

They are corrosion-resistant, guaranteeing exceptional performance in harsh conditions.

• 4 bar nitrogen pre-charge

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• Air valve with sealing cap eliminates leak

• Food grade approved high-grade diaphragm ACS

• AS/NZS4020

• Complies to BS EN 13831

• Thermal Expansion

• Booster and Borehole systems

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• HVAC (Heating, Ventilation and Air Conditioning) minimum thickness of 55 micron in Almond

• Air valve with sealing cap eliminates leaks

• Water hammer arresting

The size range of the tanks offers users the flexibility to choose the optimal size for their specific needs. The tanks fall into the below application groups;

Vertical standing pressure tanks include their tall, slender design, which allows them to be installed in areas with limited horizontal space while maximising vertical space utilisation. 

Vertical standing pressure tanks include their tall, slender design, which allows them to be installed in areas with limited horizontal space while maximising vertical space utilisation. 

Disclaimer: Every effort has been made to publish the correct details in this website. No responsibility will be taken for errors, omissions or changes in product specifications.

White International is the industry leader in Pumps &  drinking water systems.