How To Drain A Central Heating System

Draining your central heating system is advised whilst performing any repairs as it helps to ensure that there is no chance of water leaking out. Within this article, we walk you through the exact steps on how to drain a central heating system.

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How To Drain Central Heating System
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Whether you are repairing a leak or replacing a radiator, you may need to drain the central heating system in your home. Although it can be time consuming, it’s good practice as it helps to remove any sludge or limescale build up. It also gives you complete peace of mind that there won’t be any water leaks whilst carrying out the work.

Below you can find the steps to drain a central heating system with the photos taken from a recent radiator replacement at my house on the top floor.

What You’ll Need

  • Hose pipe
  • Adjustable spanner
  • Jubilee Clip
  • Radiator key
  • Towel (to clean any spillages)

How To Drain A Central Heating System


1. Switch Off The Boiler

Before you begin to fix any leaks or replace any radiators, you will want ensure that you switch off the boiler beforehand. This is a safety measure and provides you with complete peace of mind whilst carrying out any repairs.

2. Connect The Hose Pipe

With the boiler switched off, you are now ready to drain the central heating system by firstly locating the drain off valve. Once located, attach a hose pipe to the drain valve and secure it using a jubilee clip. If it isn’t securely attached, you run the risk of dirty water from the central heating system spilling all over your floor.

3. Direct The Hose Pipe Outside

The next step is to direct the hose pipe outside of your home as we did in the below photo. If it doesn’t reach, we would recommend buying a new hose pipe because it’s a crucial part of draining your central heating system.

How To Drain A Central Heating System

4. Open The Drain Valve

Now that you have setup the draining of water, use an adjustable spanner to open the drain valve.

5. Open The Bleed Valves

In order to drain the water at a much faster rate, you can open the bleed valves of the radiators. Whilst you are opening them, you should be able to hear the air being sucked from the central heating system.

6. Check Water Is Draining Out

Once the drain valve and bleed valves are open, double check that water is being drained from the central heating system. The length of time it takes to completely drain out can vary but most systems take between 10 to 15 minutes.

Once you are happy that all of the water has been drained, you can close the radiator bleed valves. After that, you can proceed to close the drain valve and remove the hose pipe. However, whilst handling the hose pipe, be warned that there may be some water still inside of the pipe, therefore walk straight outside with it.

Conclusion

Although it may seem daunting at first, to drain a central heating system is relatively straightforward. As long as you securely attach the hose pipe, there should be no issues whatsoever and once drained, you can happily complete any repair work to the radiators in your house. If you have any questions, feel free to get in touch and we can provide our advice where possible.

The Author Who Worked On This Article

author dan darimo

Dan Morgan

As a keen DIY’er, gardener and somebody that loves the latest tech, Dan is someone that brings years of experience in multiple trades. Since buying his first house, he has been obsessed with renovating properties and filling it with the latest products. This has led him down the road of testing hundreds of products and creating in-depth “how-to” and informative guides that offer his first-hand experience. Other interests include working on cars, keeping fit through sports or his home gym, caravanning and drinking great coffee.

If you would like to read more about Darimo and the authors, you can visit our about page. This goes into great detail regarding how we test products, create our guides and everything else.

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