Air separator Termojet Dn25 (1") 110°C/10bar

The Termojet TJV6G25 air separator is a device for deep deaeration of heating systems: it removes microbubbles and dissolved gases that are invisible to the naked eye but continuously circulate in the heat-transfer fluid. It is installed directly after the boiler on the supply pipeline DN25 and immediately after start-up begins to «collect» air from the entire system volume.

Technical Specifications

How It Works

The heat-transfer fluid enters the enlarged separator chamber — the flow velocity drops sharply. Inside, a coalescent insert made of welded copper wires is placed: microbubbles adhere to the wire surfaces, attract each other, and merge into larger bubbles. These rise upward and are discharged through the built-in automatic air vent. The process is continuous — the separator «cleans» the system throughout the entire season without any action from the installer.

Where and How It Is Used

• Immediately after a gas or condensing boiler. The hottest point of the system is exactly where microbubbles are released from the heat-transfer fluid most actively. DN25 (G1") matches the standard connection of boilers up to 25–30 kW.
• New system after start-up. When filled with water, a huge amount of dissolved gas is present in the pipes. The separator removes it within the first few days of operation — noises disappear and radiators heat evenly.
• Renovation of an old system. When adding new circuits or replacing pipes, fresh air enters the system — the separator absorbs it quickly and without manual intervention.
• Underfloor heating + radiators. Systems with mixed circuits are particularly prone to airlocks in underfloor heating manifolds — the separator on the supply pipeline protects all circuits simultaneously.
• Combined with a dirt separator. For complete system protection, install a dirt separator DN25 on the return pipeline — together they provide comprehensive heat-transfer fluid purification. Research has proven: simultaneous use of air and dirt separators saves up to 13% on gas.

Advantages of Termojet TJV6G25

• Coalescent insert made of welded copper wires — large specific surface area for merging microbubbles, efficiency on par with leading European equivalents.
• Install once and never come back: the separator has no replaceable filter element; the coalescent insert does not clog.
• Minimal pressure drop — does not affect the system hydraulics.
• If simultaneous removal of both air and dirt is needed — consider the air and dirt separator DN25: one solution in one body.

Frequently Asked Questions

Why do you need an air separator if there is an automatic air vent?
An automatic air vent removes free (large) air that has accumulated at high points. But microbubbles smaller than 1 mm do not rise on their own — they circulate with the heat-transfer fluid, absorb heat, accelerate corrosion, and wear out the pump. The air separator collects these microbubbles through the coalescent insert and removes them permanently — regardless of where the device is installed.

Is an angled version needed?
If space after the boiler is limited and there is no straight pipe section for mounting a straight separator — pay attention to the angled air separator DN25: a 90° connection simplifies installation in narrow boiler rooms and technical cabinets.