VAREM EXTRAVAREM LR expansion vessel for heating systems 25 l, 3/4", 6 bar

VAREM EXTRAVAREM LR 25 L is a diaphragm expansion vessel designed for closed water-based heating systems. It compensates for the increase in heating-water volume as temperature rises and helps maintain stable pressure within the system, reducing pressure fluctuations during normal heating and cooling cycles.

The EXTRAVAREM LR range uses a fixed membrane and crimped-flange construction. The membrane separates the heating medium from the pressurised air chamber. As the heating water warms and expands, the additional volume enters the vessel and compresses the air chamber; as the system cools, the water returns to the heating circuit.

Model UR025231CS000000 has a nominal capacity of 25 litres, a maximum working pressure of 6 bar, a standard factory pre-charge of 1.5 bar and a 3/4" connection. The manufacturer's specified dimensions are 290 × 460 mm.

The vessel is designed for operation with water from -10 to +99 °C. VAREM's conformity documentation for the EXTRAVAREM LR 12–25 L group specifies PS 6 bar, test pressure PT 9 bar and a standard pre-charge pressure of 1.5 bar.

VAREM does not recommend water mixed with ethylene or propylene glycol as the standard application for the EXTRAVAREM LR range. Where glycol is used, its concentration must not exceed 20%, and the maximum fluid temperature is +70 °C. With water, the vessel can operate up to +99 °C.

EXTRAVAREM LR vessels are not suitable for potable-water applications. The range is designed specifically for heating systems; potable-water and sanitary applications require a VAREM vessel intended for that purpose.

For its heating range up to 400 litres, VAREM specifies a galvanised-steel flange, standard 1.5 bar pre-charge and red finish. The 25-litre model has a packaging volume of 0.041 m³, with 63 units per pallet.

The 25-litre model is subject to CE marking under the PED. With a PS × V value of 150, it falls within the PED Category I range stated by VAREM. The EXTRAVAREM LR 25 L model is also included in the manufacturer's conformity documentation according to EN 13831.

Technical information