JWD Heating & Plumbing

How To Bleed Radiator Heating

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

A properly functioning heating system is essential for keeping your home warm and comfortable, especially during the colder months. If your radiators aren’t heating up properly—warm at the bottom but cold at the top—they may have trapped air inside. This common issue affects the overall performance of your home heating.

Knowing how to bleed a radiator is a quick and simple way to fix the problem. It helps improve heating efficiency and can even lower your energy bills. Follow this step-by-step guide to bleed your radiator safely and effectively.

Step 1: Gather Your Tools

Before you start, make sure you have the following:

  • A radiator bleed key (available at most hardware stores)

  • A cloth or small container to catch any drips

  • Gloves (optional, but helpful)

Step 2: Turn Off the Heating

Make sure your central heating is turned off. Let the system cool down completely—this prevents any hot water from escaping when you start the bleeding process.

Step 3: Locate the Bleed Valve

You’ll find the bleed valve at the top of your radiator, usually on one end. It looks like a small square or slotted screw.

Step 4: Bleed the Radiator

Insert the radiator key into the valve and turn it slowly anti-clockwise. You should hear a hissing sound as the air escapes. Hold your cloth or container under the valve to catch any drips.

Step 5: Close the Valve

When a steady stream of water begins to come out, that means all the air has been released. Turn the valve clockwise to close it. Don’t over-tighten it.

Step 6: Check Your Boiler Pressure

After bleeding, check the boiler pressure gauge. Bleeding radiators can reduce pressure slightly. If it’s too low, top up your system using the manufacturer’s instructions.

Step 7: Turn the Heating Back On

Switch your heating system back on and check the radiator. It should now be heating evenly from top to bottom. If cold spots remain, repeat the bleeding process.

When to Call a Professional

If problems persist—such as cold spots, strange noises, or a significant pressure drop—it may be time to call a professional. At JWD Heating & Plumbing, we’ve been solving home heating issues for over 20 years. Our expert engineers can diagnose and repair any faults quickly and reliably.

How to Bleed Radiator Heating – Final Thoughts

Regular radiator maintenance, including bleeding, is key to keeping your heating system running smoothly. If you’re unsure about the process or have concerns about your home’s heating, get in touch with JWD Heating & Plumbing today. We’re here to help!