Air separator Termojet DN25 (1") 110°C/10bar TJ-CA-DN25

The TJ-CA-DN25 air separator removes microbubbles and dissolved gas from the heating fluid in heating systems with a DN25 (1″) connection. Invisible microbubbles reduce heat transfer efficiency, cause pipe noise, and accelerate corrosion. The separator resolves all three problems automatically, without maintenance. Maximum temperature 110°C, pressure 10 bar.

Technical Specifications

How It Works

The heating fluid enters the expanded separator chamber and the flow velocity drops sharply. The coalescing insert with a honeycomb structure of welded copper wires increases the contact surface area: microbubbles adhere to the insert wires, approach each other, and merge into larger bubbles. These rise upward and are discharged through the automatic air vent. The cycle repeats continuously — without any maintenance.

Where It Is Used

• After the boiler (gas or solid fuel). The hottest point in the system — where gas solubility is at its lowest and microbubbles leave the heating fluid most actively. The separator is installed immediately after the boiler on the supply pipe.
• New system. On first startup the heating fluid contains the maximum amount of dissolved air — the separator deaerates the system within the first few weeks of operation.
• Noisy system. Gurgling and knocking in pipes or radiators is a sign of microbubbles. The separator eliminates the cause of the noise, not the symptom.
• Cold radiators with a hot supply. Air locks block circulation in radiator sections — the separator removes them automatically.
• Solar DHW systems. When the collector heats the fluid, dissolved gas actively leaves the heating medium — the separator prevents gas pockets from accumulating in the circuit.

Advantages

• Maintenance-free. The automatic air vent discharges air continuously — no manual intervention after installation.
• Removes microbubbles. Unlike a Schrader valve or an automatic air vent, the separator captures invisible bubbles smaller than 1 mm — which circulate and do not rise on their own.
• Low pressure drop. The coalescing insert creates no significant hydraulic resistance at the rated flow of 2,0 m³/h.
• High thermal resistance. 110°C — full compatibility with condensing and standard boilers.

Frequently Asked Questions

Why use an air separator if each radiator already has a bleed valve?
A bleed valve removes only free air — large bubbles and air pockets that have already collected at the top of the radiator. Microbubbles (smaller than 1 mm) are invisible to and cannot be removed by a bleed valve — they keep circulating, causing noise, uneven heating, and corrosion. The TJ-CA-DN25 separator captures precisely these invisible bubbles and removes them permanently. If protection against dirt is also required, consider the combined air and dirt separator DN25.

Where is it better to install — on the supply or the return?
Optimally on the supply pipe immediately after the boiler: that is where the heating fluid is hottest and gas leaves it most actively. The return pipe is appropriate only if the supply is already occupied or structurally inaccessible. Also browse the Termojet separator catalogue.