Expansion vessel Reflex S 25 L model 9702900, diaphragm tank, 25-liter capacity

Reflex S 25 L model 9702900 is a diaphragm expansion vessel with a nominal capacity of 25 liters, designed for heating and hot water systems. The internal membrane separates the system fluid from the precharged air cushion, allowing the vessel to absorb pressure fluctuations and compensate for thermal expansion. The device is suitable for domestic and light commercial installations where stable system pressure and protection of circulation pumps and safety valves are required.

Advantages

The diaphragm design prevents contact between the system fluid and the air cushion, reducing the risk of corrosion and loss of precharge. The compact cylindrical body enables wall or floor mounting in plant rooms with limited space. By smoothing pressure peaks, the vessel reduces pump cycling and wear on system components, improving operational stability. The robust construction and compatibility with standard heating system connections ensure straightforward integration.

Suitable for

• Residential central heating systems
• Domestic hot water installations
• Small commercial or light industrial heating circuits
• Systems requiring pressure compensation and reduced pump cycling

Key specifications

• Nominal volume: 25 liters
• Diaphragm (membrane) type: separates air and system fluid
• Function: compensates thermal expansion and absorbs pressure fluctuations
• Typical mounting: wall or floor installation in plant rooms
• Suitable media: water-based heating and hot water systems

How to use

Install the expansion vessel in the heating circuit according to system design and local regulations, ensuring correct orientation and secure mounting. Connect the vessel to the system using appropriate fittings and check for leaks. Verify and set the precharge pressure on the air side to match the static system pressure before commissioning. During commissioning, monitor system pressure while filling and heating to confirm the vessel is compensating expansion correctly.

Usage recommendations

Regularly inspect the vessel and verify the air precharge pressure during routine maintenance intervals. Check for signs of membrane failure such as continuous loss of system pressure or frequent pump start/stop cycles. Replace the vessel if the membrane is damaged or if the unit no longer maintains the correct precharge pressure.