Expansion vessel VAREM LR CE 18 L 3/4" gas connection, max pressure 6 bar

The VAREM LR CE 18 L expansion vessel with a 3/4" gas connection and maximum working pressure of 6 bar is designed to control pressure changes caused by thermal expansion in closed heating and hot water systems. With an 18-litre nominal volume and a compact cylindrical body, this diaphragm vessel separates the system fluid from the pre-charged gas chamber, maintaining stable pressure and protecting pipes, pumps and valves from pressure spikes and water hammer. The vessel is suitable for domestic and small commercial installations where limited space and reliable pressure management are required.

Advantages

The VAREM LR CE 18 L features a durable elastomer diaphragm that ensures a consistent separation between water and gas, reducing air absorption and loss of pre-charge. Its 3/4" gas connection provides compatibility with common plumbing fittings and allows straightforward installation and servicing. Rated for a maximum working pressure of 6 bar, the vessel is appropriate for typical low- to medium-pressure hydronic systems. The compact 18-litre capacity offers an effective balance between system protection and space efficiency.

Suitable for (tasks / use cases)

• Residential central heating systems
• Small commercial boilers and hydronic circuits
• Domestic hot water systems with closed circuits
• Solar thermal installations with compact expansion requirements

Key specifications

• Nominal volume: 18 litres
• Connection type: 3/4" gas connection
• Maximum working pressure: 6 bar
• Vessel type: diaphragm (pre-charged gas chamber, water-separated)
• Application: closed heating and hot water systems, solar thermal circuits

How to use

Mount the expansion vessel on a stable support close to the boiler or within the hydronic circuit using appropriate brackets or fittings. Before connecting, check and adjust the pre-charge pressure of the gas chamber to match the static fill pressure of the system, typically measured with the circuit drained or at recommended system pressure. Connect the 3/4" gas fitting to the system piping, ensuring sealed threads and correct orientation for access during maintenance. After installation, pressurise the heating system and inspect for leaks, then verify that the vessel responds to temperature-related pressure changes during initial operation.

Usage recommendations

Check the vessel pre-charge periodically and before winter commissioning; if the diaphragm shows signs of deterioration or the vessel fails to control pressure, replace it. Use compatible fittings and isolation valves to allow easy removal for maintenance. For systems with higher fill pressures or larger thermal expansion volumes, select a vessel with appropriate capacity and pressure rating.