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Heating engineer · Brussels and Wallonia
Bleeding a radiator
A radiator that's hot at the bottom but lukewarm at the top, or that gurgles, has air in it. Bleeding it takes a few minutes and all you need is a radiator key.
Before you start
- A radiator key (from a DIY shop) or a flat screwdriver, depending on the valve.
- A cloth and a small container for the water.
- The water can be hot: protect your hands.
Step by step
- Open the valves on all radiators and turn the thermostat up.
- Wait until the radiators are hot, then switch the boiler off.
- Wait about ten minutes for them to cool down.
- Start with the lowest radiator in the house, then work your way up floor by floor.
- Open the bleed valve with the key, holding the cloth against it: the air hisses out.
- Close it as soon as water comes out.
- Switch the boiler back on and check the pressure: if it's too low, top it up (see the pressure guide).
Call us if…
- The radiator stays cold even after bleeding.
- You have to bleed very often: air is getting into the system somewhere.
- The bleed valve is stuck or leaking.
A breakdown, a question? Get in touch.
Call us or message us on WhatsApp. Or leave your number, with a photo of the boiler if you like: we'll call you back.
