Do You Bleed A Radiator Hot Or Cold?

Do You Bleed A Radiator Hot Or Cold

Do you bleed a radiator hot or cold? The purpose of this post is to directly answer this question for you. so read on…

Bleeding a radiator is not only easy but also an essential part of keeping your heating system working efficiently and making your house a warm place to be in. By bleeding a radiator, you let the air trapped inside escape so that all the water in the heater can get heated properly and there are no cold spots. Switch off all the radiators and start bleeding them. Furthermore, it is always essential to bleed a radiator when it is cold to avoid getting scalds or burns from the hot air.

How often should you bleed a radiator?

It would help if you bled a radiator once every year before winter starts so that you do not suffer in the cold.

When Should You Bleed a Radiator?

There are some things that you should look out for which indicate that your radiators need to bleed. If you hear a gurgling, clucking, or even a flowing sound, bleeding needs to be done immediately. Sometimes, the presence of cold spots also means that bleeding needs to be done.

Do You Bleed A Radiator Hot Or Cold?

How to bleed a radiator?

  • To bleed a radiator, you will need the following tools:
  • Radiator bleed key
  • A cloth
  • Container/ towel

Let’s now move on to the steps for bleeding a radiator. These steps are pretty simple and easy to follow.

Step 1- Identification of cold spots

You will first start by switching on the heating system so that all the radiators can warm up. Next, run your hand on each radiator to check if it has any cold spots. If there are any other signs as mentioned above as well, then that radiator definitely needs bleeding. We will advise you to wear thin pair of gloves so that your hand doesn’t get a burn from a hot pipe. Moreover, make a list of all the radiators that need bleeding.

Step 2- Cooling of hot water in radiator

It’s now time to switch off your central heating system and wait for some while so that the hot water in the radiator can cool down. This step is crucial because if you forget to switch off your heating system and starting bleeding, you will burn yourself.

Step 3- Locate the first radiator for bleeding

It is always advisable to first bleed the radiator which is furthest away from the boiler. Also, place a container/ towel under the radiator you plan on bleeding so that the flooring or carpet dont get dirty.

Step 4- Bleeding the radiator

This is the step where the real magic happens. Insert the bleed key in the bleed valve. This valve is often found at the top of a corner. Once the key is inserted in the bleed valve and you feel like that it is locked, turn the valve anticlockwise. Be cautious and maintain a distance when doing this because the air which will get released might be hot. You will hear a hissing sound as the air escapes.

Once the air from the radiator has been completely bled, water starts rushing out. We advise you not to open the valve completely (half a turn is more than enough). This is so that no mishap occurs and all the water doesn’t come out. If you open only half the valve, water will drip and not rush out once all the air has escaped.

Step 5- Closing the Bleed Valve

Now that all the air has escaped, turn the valve clockwise. Be careful and not over tighten the valve.
Now, bleed all the other radiators in your house so that you can enjoy a nice warm house.

Step 6- Pressure of the heating system

After you have completed bleeding all the radiators, you will have to check the pressure of your heating system and adjust it. During the process of bleeding, some water from the radiator is lost. If a lot of the water is a lot, the pressure of your heating system needs to adjust so that the needle gauge on the boiler faces green. The ideal pressure can make a lot of difference in warming up your house.

Do You Bleed A Radiator Hot Or Cold

How long does it take to bleed a radiator?

You have to bleed your radiator cold as long as the hissing sound continues and no water drips. The moment the hissing sound stops and water begins to drip, close the bleeding valve. This entire procedure takes about 20 to 30 seconds.

Be careful when bleeding a radiator and make sure that isn’t too hot. The entire procedure is simple and easy to follow. We hope you found the guide useful!


I am John Oakley. I love to share tips and reviews on products to keep our homes warm and comfortable.

Recent Posts