VAREM EXTRAVAREM LR expansion vessel for heating systems 12 l, 3/4", 6 bar

VAREM EXTRAVAREM LR 12 L is a diaphragm expansion vessel designed for closed water-based heating systems. It compensates for the increase in water volume caused by rising temperature and helps maintain stable system pressure, reducing excessive pressure fluctuations in boilers, heat pumps, pipework, valves and other heating-system components.

The EXTRAVAREM LR series uses a fixed membrane that separates the heating water from the pressurised air chamber. As the heating medium expands, the additional volume enters the vessel and compresses the air chamber. When the system cools, the water is returned to the heating circuit. The vessel uses a galvanised carbon-steel counterflange.

The nominal capacity is 12 litres, maximum operating pressure is 6 bar, and the factory pre-charge pressure is 1.5 bar. Connection size is 3/4", with overall dimensions of 270 × 310 mm.

The vessel is designed for operation with water from -10 to +99 °C, making it suitable for conventional heating, underfloor heating, boiler and heat-pump circuits where its capacity and pressure rating meet the system design requirements.

VAREM does not recommend water/glycol mixtures as the primary application for the EXTRAVAREM LR range. Where ethylene or propylene glycol is used, the permitted concentration is limited to 20%, with a maximum fluid temperature of +70 °C. With water, operation is permitted up to +99 °C.

EXTRAVAREM LR vessels are not suitable for potable water. Domestic hot-water and potable-water installations require an expansion vessel from a VAREM range specifically approved for those applications.

The vessel is finished in red, the standard colour used by VAREM for this heating range. The heating-line specification includes a galvanised steel flange and a standard 1.5 bar pre-charge.

The 12-litre model is covered by VAREM's CE/PED conformity documentation. The manufacturer's declaration lists EXTRAVAREM LR 12–25 L vessels with PS 6 bar, 1.5 bar standard pre-charge and an operating temperature range of -10 to +99 °C in accordance with EN 13831.

Technical information