How to bleed an aluminium radiator on a sealed system?

Outlined below are the steps to follow to bleed an Afinia aluminium radiator that is connected to a sealed system – if you are unsure about what type of system you have or if you are unsure how to bleed your radiators correctly, please speak to your heating engineer.

1. Turn off any heating or hot water demand and check the lock shield and thermostatic radiator valves are both open.

2. Take a note of the system fill pressure by manoeuvring the red indicator on the pressure gauge as appropriate

Pressure gaugePressure gauge

3. Insert the radiator key into the bleed valve on your radiator and place a cloth underneath to capture any water. Twist the radiator key anti-clockwise until you hear a hissing sound as the air escapes - if this continues for a prolonged period or the hissing stops and water is not apparent, temporarily close the bleed valve and check the system pressure at the system fill point.

4. If the pressure is low, you will need to top up the pressure to the red indicator - this is normally set to 0.5 bar for a single storey dwelling and 1 bar for a 2 storey dwelling. You may need to repeat this process several times.

5. Close the bleed valve when water starts leaking from the valve and re-check the system pressure at the system fill point and top up as required.

6. If switched off, turn on any heating or hot water demands and return to both radiator and system fill point to re-check for leaks.

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