Expansion Vessel Comap Solarix 25/2.5 (10 bar) for Solar and Heating Systems

Comap Solarix 25/2.5 (10 bar) is a diaphragm expansion vessel designed for closed solar and heating systems. With a nominal volume of 25 litres and a factory pre-charge of 2.5 bar, the vessel absorbs thermal expansion of the heat transfer fluid, stabilises system pressure and reduces the risk of overpressure events. Constructed for domestic and small commercial installations, this unit is suitable for solar thermal loops and hydronic heating circuits where a compact, diaphragm-type buffer is required.

Advantages

The diaphragm design separates the compressible gas chamber from the liquid side to prevent gas absorption and prolong membrane life. A 10 bar maximum allowable working pressure provides a safety margin for higher-pressure heating or solar systems. The vessel’s 25-litre capacity balances space efficiency with sufficient expansion volume for typical small installations. Durable construction and standard connection options make the unit compatible with common system layouts.

Suitable for

• Closed solar thermal systems (domestic hot water and solar collectors)
• Hydronic heating systems in single-family homes
• Small commercial heating circuits requiring a 25 L expansion volume
• Systems where a 2.5 bar pre-charge is appropriate for pump head and static pressure

When it may not be suitable

This expansion vessel is not intended for open systems or potable water expansion applications where direct potable water contact is required. Systems that need a larger expansion volume, a different pre-charge pressure, or an alternative maximum working pressure should select a vessel sized and rated specifically for those conditions.

Key specifications

• Type: Diaphragm (membrane) expansion vessel
• Nominal volume: 25 litres
• Factory pre-charge pressure: 2.5 bar
• Maximum allowable working pressure: 10 bar
• Application: Closed solar and hydronic heating circuits

How to use

Install the expansion vessel on the pressure side of the system, typically near the boiler, pump or solar station, using the appropriate shut-off and isolation valves. Verify and adjust the pre-charge pressure with the vessel isolated and drained from the system if necessary; the correct pre-charge equals the static system pressure at the vessel location. Position the vessel upright and secure it to prevent movement. Periodically check the pre-charge and inspect the vessel for leaks or visible damage as part of routine system maintenance.

What to consider before purchase

• Confirm the required expansion volume for your system based on total fluid volume and maximum temperature rise
• Ensure the factory pre-charge (2.5 bar) matches or can be adjusted to your system static pressure
• Verify compatibility with system maximum pressure; this vessel is rated to 10 bar
• Check physical dimensions and mounting requirements to ensure fit in available space

Usage recommendations

For reliable operation, set the vessel pre-charge to match the system’s static pressure and re-check it after commissioning and periodically during service. Use isolation valves and a pressure gauge nearby to facilitate maintenance. Replace the vessel if the diaphragm shows signs of failure, loss of pre-charge that cannot be restored, or visible corrosion.