Pressure expansion vessel, 12 l, 8 bar, 3/4"

Product detailed description

Pressure expansion vessels are essential components in closed heating and cooling systems where thermal expansion of water or glycol mixtures must be accommodated. This IVAR model is commonly used in residential and commercial buildings, including underfloor heating systems, heat pump circuits, and central heating installations. Installers must ensure the vessel is correctly sized and positioned to maintain system pressure and prevent damage from overpressure. The vessel is designed for systems operating between -10 °C and +99 °C, with a recommended maximum operating temperature of +80 °C for long-term reliability.

The vessel is constructed with an SBR membrane, which is resistant to thermal cycling and compatible with non-freezing mixtures up to 50 % concentration. It is mounted vertically and requires secure fixing to prevent movement during operation. The 3/4 inch connection is standard for most domestic and light commercial systems, and the vessel must be connected to the system via a non-return valve to prevent backflow. The vessel is CE marked in accordance with EU pressure equipment directive 97/23/EC.

Technical parameters

Installation and connection

Installation should be carried out by qualified personnel following the manufacturer’s guidelines. The vessel must be connected to the system using a 3/4 inch threaded connection, typically via a union or compression fitting. It is important to ensure the vessel is fully charged with air at the factory pressure setting before connecting to the system. A pressure gauge and air valve should be installed for periodic checks. Common installation errors include incorrect orientation (horizontal mounting), failure to secure the vessel, and incorrect air pressure settings. The vessel should be mounted in an accessible location for maintenance and inspection.

Compatibility and accessories

This pressure expansion vessel is compatible with most closed heating and cooling systems that operate within the specified temperature and pressure range. It is typically used in conjunction with pressure-reducing valves, safety valves, and pressure gauges. Accessories such as mounting brackets and air pressure adjustment tools may be required for installation and maintenance. No specific related products are listed for this model.

Technical background for designers

The operating principle of the vessel is based on the separation of water and air by a flexible membrane. As the system heats up, the water expands and compresses the air chamber, maintaining system pressure. The SBR membrane is chosen for its resistance to thermal cycling and compatibility with glycol mixtures. The vessel must be sized according to the system’s expansion volume and operating pressure. The service life is influenced by the quality of the membrane, the stability of the air charge, and the operating conditions. The vessel must be integrated into the system with a non-return valve to prevent backflow and ensure correct pressure regulation.

Service and operation

Periodic checks of the air pressure and membrane integrity are recommended to ensure continued performance. The vessel should be inspected for signs of leakage, corrosion, or damage. No specific service intervals are provided in the brief. If the vessel is found to be under- or over-pressurised, the air charge should be adjusted using a pressure gauge and air valve. In the event of membrane failure, the vessel should be replaced to prevent system damage.

Frequently asked questions

Can the vessel be used with glycol mixtures?
Yes, the vessel is suitable for use with non-freezing mixtures up to 50 % concentration.

Is the vessel suitable for outdoor installation?
No, the vessel should be installed in a protected location to avoid exposure to extreme weather conditions.

Can the vessel be used in a cooling system?
Yes, the vessel is suitable for both heating and cooling systems operating within the specified temperature range.

What is the maximum recommended operating temperature?
The recommended maximum operating temperature is +80 °C for long-term reliability.