How to bleed a radiator

How to Bleed a Radiator: A Step-by-Step Guide

A cold patch at the top of your radiator? That’s a telltale sign it needs bleeding! Trapped air in your central heating system can prevent your radiators from heating efficiently, leading to higher energy bills and a chilly home. Thankfully, bleeding a radiator is a simple DIY task you can tackle yourself. Here’s a step-by-step guide tailored to UK central heating systems.

Why Bleed Your Radiators?

Over time, air can accumulate in your radiators, creating a barrier that prevents hot water from circulating properly. This trapped air results in cold spots, reduced heating efficiency, and can even lead to corrosion within your system.

What You’ll Need:

• Radiator bleed key (available at most DIY stores)
• Old cloth or rag
• Small container or bowl

Step-by-Step Guide:

1. Turn Off Your Heating: Before you begin, switch off your central heating system and allow your radiators to cool down completely. This prevents hot water from spraying out when you bleed them.
2. Locate the Bleed Valve: The bleed valve is usually located at the top corner of the radiator. It’s a small square or slotted valve.
3. Prepare for Water: Place your cloth or rag underneath the bleed valve to catch any water that may escape. Have your container or bowl ready to catch more substantial water flow.
4. Insert the Bleed Key: Insert the radiator bleed key into the valve.
5. Turn the Key Slowly: Gently turn the bleed key counterclockwise. You should hear a hissing sound as the trapped air escapes.
6. Wait for Water: Continue turning the key until water starts to trickle out. Once water appears, it means all the air has been released.
7. Close the Valve: Carefully tighten the bleed valve by turning the key clockwise. Don’t overtighten it, as this can damage the valve.
8. Repeat for All Radiators: Repeat the process for all radiators in your home, starting with the radiator furthest from your boiler.
9. Check Your Boiler Pressure: After bleeding your radiators, check your boiler pressure gauge. Bleeding radiators can sometimes cause a drop in pressure. If the pressure is too low, you may need to top it up according to your boiler manufacturer’s instructions.
10. Turn Your Heating Back On: Switch your central heating back on and check that all your radiators are heating up evenly.

Tips and Considerations:

• If you have a combi boiler, you may need to repressurise the system after bleeding the radiators. Consult your boiler’s manual for specific instructions.
• If you experience persistent air in your radiators, it may indicate a more significant issue with your central heating system. In this case, it’s best to consult a qualified heating engineer.
• If you have a thermostatic radiator valve, make sure it is fully open before bleeding the radiator.
• If you have very old radiators, be very gentle with the bleed valve, as they can sometimes be fragile.

By following these simple steps, you can keep your radiators working efficiently and your home warm and cozy throughout the colder months.