Expansion Vessel Meibes BASEFLEX 50/1.5, 6 bar for central heating

Meibes BASEFLEX 50/1.5 is an expansion vessel for central heating systems with a nominal capacity of 50 liters and a maximum working pressure of 6 bar. The vessel compensates for thermal expansion of the heating medium, helps stabilize system pressure and reduces the frequency of automatic filling cycles. It is designed for installation in residential and small commercial heating circuits where reliable pressure management and protection of pumps, valves and piping are required.

Advantages

The BASEFLEX construction integrates a durable elastomer membrane that separates the air cushion from the heating fluid, ensuring consistent precharge performance and reducing air ingress. The compact vertical design and standard connection fittings simplify installation and replacement in existing systems. Rated for 6 bar working pressure, the vessel is suited to higher-pressure applications compared with lower-rated alternatives, providing additional margin for system safety.

Suitable for

• Domestic central heating systems
• Small commercial heating circuits
• Closed-loop boiler and heat pump installations
• Circuits requiring a 50‑litre expansion capacity and 6 bar rating

Key specifications

• Nominal volume: 50 liters
• Maximum working pressure: 6 bar
• Membrane/precharge characteristic indicated by model: 1.5
• Vertical, compact vessel design suitable for wall or floor mounting
• Material: metal vessel with elastomer membrane (membrane type construction)

How to use

Install the expansion vessel in accordance with local regulations and the heating system manufacturer’s instructions. Mount the vessel at a convenient location on the return line or near the boiler/heat pump manufacturer’s recommended point, using appropriate fittings and isolation valves. Set or verify the precharge pressure of the air side before commissioning, ensuring it matches the static system pressure requirements. Perform initial leak testing, then bring the heating system to operating temperature while checking that the vessel accommodates thermal expansion and that system pressure remains within the expected range.

Usage recommendations

Regularly check the vessel’s precharge pressure and inspect for visible corrosion or membrane failure during scheduled maintenance. If system pressure behavior changes or the vessel shows signs of failure, isolate and replace the unit to maintain system protection. Use compatible fittings and follow manufacturer guidance for mounting orientation and precharge adjustment.