Does My Radiator Need Bleeding?

If your radiator feels cold at the top but warm at the bottom — or if you hear gurgling or bubbling when the heating is on — it’s likely time to bleed it. Bleeding removes trapped air that stops hot water from circulating properly.

Signs a Radiator Needs Bleeding

• Radiator cold at the top, warm at the bottom
• Gurgling or bubbling noises
• Partially hot or uneven heat across radiators
• Heating system slow to warm up
• Visible air bubbles or low boiler pressure

Trapped air is the most common reason for uneven radiator heat — and bleeding is a simple fix most homeowners can do themselves.

How to Bleed a Radiator

1. Turn off your heating and wait for the system to cool.
2. Use a radiator key (or flathead screwdriver on some models).
3. Hold a cloth or small bowl under the bleed valve at the top corner.
4. Turn the key slowly anti-clockwise until you hear a hiss — that’s air escaping.
5. Once water starts to flow steadily, close the valve tightly.
6. Check the boiler pressure and top up if it’s dropped below 1.0 bar.

Tip: Start bleeding the radiator furthest from the boiler and work your way in.

What If Bleeding Doesn’t Fix It?

If your radiator is still cold after bleeding, or if multiple radiators are affected, there could be:

• A build-up of sludge in the system
• A faulty pump or motorised valve
• Low boiler pressure or an airlock in the system

In these cases, it’s best to book a professional heating engineer to inspect the system and carry out a flush or repair if needed.

Should I Bleed All My Radiators?

If one radiator needs bleeding, chances are others do too. It’s good practice to check all radiators once a year — ideally before winter sets in.

We Can Help With Radiator Problems

At Jones Heating, we handle more than just boilers. Whether you need a radiator bled, balanced, flushed or replaced — we’ll sort it quickly and properly.

📞 Call us: 01383 660098
🌐 More info: Radiator Repairs in Dunfermline

We cover Dunfermline, Kirkcaldy, and Fife — with fast response and honest advice to keep your heating running at its best.