Air vent FLAMCO FLEXVENT TOP 1/2" model 28515, automatic automatic vent for heating and cooling systems

FLAMCO FLEXVENT TOP 1/2" model 28515 is an automatic air vent intended for use in heating and cooling systems. Fitted with a 1/2" threaded connection, it removes trapped air from radiators, boilers and pipework to maintain steady circulation and reduce noise and corrosion. The compact design allows installation at high points in system layouts where air accumulates.

Advantages

The automatic vent operates without manual intervention, continuously discharging small amounts of air to prevent airlocks and flow disruption. By reducing trapped air, it helps lower noise levels and the risk of localized corrosion, supporting longer component life and more consistent heat transfer. Its standardized connection size simplifies replacement or integration into existing systems.

Suitable for

• Domestic central heating systems including radiators and boilers
• Light commercial heating and cooling installations
• High points of pipework, manifolds and air collection zones
• Retrofit projects where automatic air removal is required

When it may not be suitable

This device is designed for removing small volumes of entrained air and is not a substitute for system flushing or deaeration during commissioning. It may not be appropriate for large industrial systems with high flow rates or where specialized degassing equipment is specified. For systems using aggressive fluids or non-standard additives, compatibility with internal materials should be confirmed.

Key specifications

• Connection: 1/2" threaded
• Function: automatic air vent for heating and cooling circuits
• Typical installation point: high points, radiators, boilers, manifolds
• Operation: continuous automatic air discharge

How to use

Install the FLEXVENT TOP at a system high point or on radiator/boiler air vents using the 1/2" threaded connection. Ensure the vent is mounted vertically and accessible for inspection. Once connected and the system is filled and pressurised to normal operating conditions, the unit will automatically release trapped air; periodic checks can confirm proper operation and absence of leaks. If maintenance is required, isolate the section of the system and follow safe-drain procedures before removing the vent.

What to consider before purchase

• Verify the required connection size is 1/2" to match existing fittings
• Confirm suitability for the system fluid and operating pressures/temperatures
• Check available mounting space and preferred installation point (vertical orientation)
• Determine whether automatic venting alone is sufficient or if additional deaeration measures are needed

Usage recommendations

Place the automatic vent at the system's highest practical location and leave it accessible for periodic inspection. Combine with correct filling, flushing and inhibitor treatment to maintain system efficiency and minimize air-related issues.