How To Bleed A Radiator?

When it comes to keeping your home warm, there is no more important piece of equipment than your radiator. Like most household appliances, a radiator needs regular maintenance to keep your home from becoming a freezer in the winter.

Heating Headaches

If you have noticed that the heating just doesn’t seem to have the same warmth anymore, or you simply want to get ahead of the game, use these simple tips to avoid a heating headache and learn how to bleed your radiator.


The first step to bleeding a radiator is to inspect the radiator and diagnose the likely cause of the issue. This can be a tough task to get right, so if you don’t feel comfortable then it may be best to place a call to your local plumber. Radiator faults usually occur because of cold air being trapped, which then stops the flow of warm air coming into your home.

Some of the more common causes like leaks and pressure are easier to diagnose than a wider heating system issue. Be careful when touching your radiator as it may be very hot, but be sure to check it over thoroughly. Once you understand the cause of the issue, it is easier to bleed and rectify the air intake.

Find the key

Once you understand the issue and feel confident to bleed the radiator yourself, it is time to find the key. A radiator key is crucial to the bleeding process.

radiator key

A radiator key is a simple but effective tool designed to release the valve on your radiator.

A radiator key can be purchased from most hardware stores if you don’t have one. Another step may be to check your toolbox, some valves can be released with smaller implements such as a screwdriver. Once you have the key, then you can continue onto the next stage of the process.

Cool it down

Make sure you switch off your heating system and give the radiator contents ample time to settle. Using the valve can introduce air into the system which can cause further issues if done while the system is still active or unsettled. A rule of thumb to follow at this stage is to wait until every part of the radiator is cool to the touch.

Catch and release

Once cooled, you are ready to bleed the air from your radiator. Make sure both the entry and exit valves are open before you start to bleed the radiator.

Next, you need to locate the bleed screw which will be attached to the bleed valve. Grab that handy key and turn the screw to start the bleed. You will hear the air escaping the radiator as the water begins to fill that space.

At this point, you want to have a small bowl to catch the droplets of water which will start flowing slowly from your radiator.

Once you see the water begin to spray from the bleed valve turn the key the opposite way and close the other valves. The bleeding process is complete.

Repeat and inspect

If you have multiple radiators around your home you will need to repeat the process for each one. Then just as you began, it is time to inspect. Check the pressure gauge on the radiators around your home.

If the pressure has dropped below 12-15 psi the pressure is too low, which will stop heating getting to all areas of your home.

Don’t panic though, if you have an automatic fill system the boiler will top up in no time at all. If you don’t have an automatic fill system, then you will need to top up the boiler with water manually until you hit the 12-15 psi mark.


When your radiators are playing up, you should first try to identify the cause of the issue as there are a number of possibilities as to why they’re not working properly. Once you have identified the problem, try to fix the problem yourself if you have prior experience, but be careful when doing so. Radiators can be tricky business, which is why if you aren’t confident you should contact a plumber. If you are confident though, use this process to relieve the radiator and your heating headache.

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