Why bleeding helps
Air rises to the top of a radiator and stops hot water filling the whole panel, so the top stays cold and the room never quite warms up. Letting the air out lets the radiator fill properly again. It’s a common cause of cold radiators.
What you’ll need
A radiator bleed key (cheap from any DIY shop) and a cloth or small container to catch drips. That’s it.
Step by step
Turn the heating off and let the radiators cool. Fit the key to the bleed valve at the top corner and turn slowly anti-clockwise — you’ll hear air hiss out. As soon as water dribbles out steadily, close it again. Wipe up any drips.
Re-check the pressure
Bleeding releases pressure from the system, so check the boiler gauge afterwards. If it’s dropped below about 1 bar, top it up via the filling loop. If you’re forever topping up, that’s worth investigating.
Bled the radiators and still cold, or the pressure won’t hold? We’ll find out why — sludge, a valve or a leak — and sort it. South Manchester and Cheshire.
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