How to bleed a radiator – your step-by-step guide

We’ve all experienced it. You turn on the heating and something isn’t quite right. You might be hearing strange noises coming from your radiators. They might have cold areas across the top. Or perhaps your radiator is not heating up at all.

No need to panic – chances are, you just need to bleed your radiators. It’s easy to do and will have your radiators working as good as new in no time. Our step-by-step guide on how to bleed a radiator shows you everything you need to do to get your home nice and warm again.

How do I know if my radiators need bleeding?

Easy. Just follow these steps:

  • Turn on your heating and wait for it to warm up
  • Feel each radiator – if it’s hot at the top and cold at the bottom, it doesn’t need bleeding
  • If it’s hot at the bottom and cold at the top, read on to find out how to bleed it

How do you bleed a radiator?

Want to watch our experts show you how it’s done? Then enjoy our video demonstration. Or if you prefer, just follow the simple steps shown in the video.

Can you bleed a radiator when the heating is on?

Granted, a new boiler isn’t cheap. But if your boiler is giving up on the regular then you know just how inconvenient and expensive that can be too. The family is freezing, while those breakdown bills pile up, so it’s worth doing your sums to figure out if a new boiler could leave you better off in the long run.

No! It’s very important to make sure your heating is off, and the radiators are cool before you bleed them. This is because radiators are filled with water and air, which is what escapes when you open the valve. When the heating is on, the water and air inside become dangerously hot – so you could scald yourself when it’s released.

What tools do I need to bleed my radiator?

  • Radiator bleed key (or flat head screwdriver for more modern radiators)
  • Cloth
  • Old towel
  • Container

You should have most of these at home anyway. But if not, they don’t cost much and can be found online or in most DIY stores.

Bleeding a radiator in two steps

1. Give it a feel

Turn on the heating and then go around the home and feel the radiators. Be careful not to burn yourself! Check for any cold patches and listen out for odd gurgling sounds. If a radiator is cold at the top, then it needs bleeding. If it’s not, then just leave it be – you don’t want to bleed a radiator that doesn’t need bleeding.

2. Release the pressure

  • Keep your old towel and container handy for each radiator you go to
  • Locate the valve and use your radiator key (or screwdriver) to open it by turning it anti-clockwise. If it’s tough to open, use the cloth to get a better grip
  • Only open it slightly until you hear the hissing noise – that’s air escaping
  • Once the sound stops and water starts streaming out, make sure you catch the water in the container
  • Now it’s time to re-tighten the valve
  • Clean up any excess and move on to the next one!

Once you’ve finished, you’ll not only be an expert in bleeding radiators, but your home will almost be back to full heating efficiency! .

What happens after you finish bleeding your radiator?

You want to make sure your hard work gets results by performing some checks. First, you need to check your boiler pressure. While it will decrease a bit after bleeding radiators, you want it to be between 1.0 to 1.5 bars when it’s switched off and approximately 2 bars when it’s on.

If the pressure is too low, your boiler will have to be re-pressurised. But don’t worry. This is easier than it sounds – find out how to re-pressurise your boiler here.

If the pressure is fine, turn the heating back on, then go back and check all your radiators. They should all be working and warming up properly, so you can get back to enjoying a cosy home again.

What is the best way to bleed a radiator?

If you follow our step-by-step guide on how to bleed a radiator, you should have no issues in making sure your radiators are working properly. However, if you’re wondering how to bleed a radiator without a bleed valve, or want to double check that you’ve bled your radiators properly, here are some handy tips:

How to bleed a radiator without a bleed valve

Before reaching out for expert help from a plumber, check the entire radiator first – sometimes valves can be hidden under layers of paint, or they can be on the back face of the radiator. If you still can’t find a bleed valve, the best course of action would be to ask for help from a plumber as they can offer alternative options.

How to check you’ve bled your radiators properly

You will know if you have bled your radiator correctly if there is not a huge drop in boiler pressure afterwards. If you do experience this, read our guide on how to increase boiler pressure.

  • Do not open the valve all the way – you could cause a big drop in boiler pressure

If your radiators still aren’t heating up, it could be a boiler issue. If this is the case, you can always get a free quote on a new one and find out how we can help you find the right boiler for your home.

How often should you bleed your radiators?

Bleeding your radiators is key for keeping your boiler running efficiently, which in turn keeps your home warm and your energy bills as low as possible.

So, when should you bleed your radiators? We recommend bleeding your radiators on a regular basis – every few months should do the trick. It’s always good to bleed your radiators after long periods without use too, like at the end of summer.

With regular bleeding, you’ll reduce strain on your boiler and ensure that your radiators are correctly warming your home.

Is my radiator broken or does it just need bleeding?

Radiators still not working properly? If your radiators are still not heating up like they should, just get in touch with us and we’ll help with any repair work for your radiators or boiler.