Expansion Vessel Comap Contra-Flex 100 L, 1.5 bar pre-charge, 6 bar max, 3/4" connection, red

Closed expansion vessel Comap Contra-Flex 100 L is designed for central heating (c.o.) systems to absorb thermal expansion and stabilize system pressure. The tank has a 100-litre capacity with a factory pre-charge of 1.5 bar and a maximum working pressure of 6 bar. It comes with a 3/4" threaded connection and a red corrosion-resistant coating for typical residential and light commercial heating installations.

Advantages

The Contra-Flex design separates the system fluid from the internal gas cushion, reducing oxidation and prolonging service life. A factory-set pre-charge of 1.5 bar enables immediate installation without initial pressurization steps for many home heating systems. The compact 100 L volume is suitable for single- and multi-loop domestic systems, while the 6 bar maximum rating provides a safety margin for varied system pressures. The red coating offers visual identification and additional surface protection against corrosion.

Suitable for

• Residential central heating systems (single- and multi-boiler installations)
• Light commercial or small apartment building heating circuits
• Systems requiring a 100 L expansion volume with a 3/4" connection
• Installations where a factory pre-charge of 1.5 bar is compatible with system static pressure

When it may not be suitable

This expansion vessel may not be suitable for high-pressure industrial systems that exceed the 6 bar maximum working pressure or for installations that require a different connection size than 3/4". Systems requiring a different pre-charge pressure or larger expansion volume should use a vessel matched to those specific parameters.

Key specifications

• Type: closed expansion vessel for central heating
• Capacity: 100 litres
• Factory pre-charge: 1.5 bar
• Maximum working pressure: 6 bar
• Connection size: 3/4" threaded
• Exterior finish: red corrosion-resistant coating

How to use

Mount the vessel at an appropriate location on the heating circuit where it can be accessed for inspection and maintenance. Ensure the system is depressurized and drained locally before making the connection. Fit the 3/4" threaded connection to the system pipework using suitable sealing methods and torque values recommended by the installer or local regulations. After installation, refill and pressurize the heating system, check the vessel pre-charge with a pressure gauge and adjust only if required to match system static pressure. Carry out leak checks and monitor system pressure during the initial heat-up cycle.

What to consider before purchase

• Confirm the vessel capacity (100 L) is appropriate for the total system volume and heat output
• Verify that the factory pre-charge of 1.5 bar suits the system static pressure or whether recharging is needed
• Check that the 3/4" connection matches your piping and fittings
• Ensure the maximum working pressure of 6 bar is sufficient for your installation

Usage recommendations

For reliable operation, inspect the expansion vessel periodically for external corrosion or damage, verify the pre-charge pressure annually, and ensure system water quality to reduce corrosion and sediment that can affect vessel performance.