Expansion vessel Meibes FLOFIX 12/4.0 10 bar – heating system accumulator 12 L, 4.0 bar pre-charge, max 10 bar

Meibes FLOFIX 12/4.0 10 bar is a 12-litre expansion vessel designed for sealed heating and hot water systems. With a factory pre-charge of 4.0 bar and a maximum allowable working pressure of 10 bar, the vessel compensates for thermal volume changes in closed circuits to stabilise system pressure and protect pumps, valves and piping. Constructed for residential and light‑commercial heating installations, it helps reduce maintenance by preventing overpressure events and maintaining reliable hydraulic balance.

Advantages

The FLOFIX expansion vessel integrates a durable bladder design and a corrosion-resistant steel shell to provide long service life under normal heating system conditions. Factory pre-charging at 4.0 bar removes the need for immediate commissioning adjustments in many applications and the 10 bar maximum working pressure covers a wide range of boiler and system configurations. Compact dimensions and standard connection fittings simplify installation in boiler rooms and distribution cabinets.

Suitable for

• Closed domestic heating systems (radiators, underfloor heating)
• Hot water circulation and sealed potable water circuits
• Light commercial heating installations and small hydronic systems
• Retrofit projects where space-efficient expansion vessels are required

Key specifications

• Nominal volume: 12 litres
• Factory pre-charge pressure: 4.0 bar
• Maximum allowable working pressure: 10 bar
• Type: diaphragm/bladder expansion vessel for closed systems
• Typical connection: standard threaded fitting for wall or bracket mounting

How to use

Install the expansion vessel on the system return line or in the designated connection point of the heating circuit, following manufacturer and local plumbing codes. Before final commissioning, verify the pre-charge pressure with a pressure gauge and adjust if system requirements differ from the factory setting. Ensure secure mechanical mounting and proper hydraulic connections, then fill and vent the system to remove trapped air. Monitor system pressure during initial operation to confirm correct vessel function.

Usage recommendations

Check the pre-charge periodically and after major system work; maintain the vessel within its rated temperature and pressure limits. If the system shows frequent pressure drops or rapid cycling of pumps, inspect the bladder integrity and connections. For precise sizing in complex or large installations, consult hydraulic calculation data or a heating professional.