Home Improvement

How to Replace a Radiator Valve

We all want to be warm and cosy during the harsh winters. Your radiators are an important part of your heating system and keeping them in good shape is vital. Parts get worn out, however, and at some point, you might need to change a radiator valve.

If that time has come, fear not! We have all the information you need to tackle this project on your own.

Table of Contents:

So, if this sounds like you:

  • Your radiator valves are old, damaged or leaking;
  • You want to learn how to change a radiator valve;
  • You’re thinking of replacing a radiator valve with a thermostatic one,

Then read on! This post is for you.

What you need

  • Washing up bowl
  • Towels
  • Jubilee clip
  • Hose
  • PTFE tape
  • Hex key
  • Plumber’s wrench
  • Adjustable spanner
  • Clean cloth
  • Wire wool

How to change a radiator valve

If you have a combi boiler system, you can do this yourself. However, for conventional systems, you will need to call a registered engineer to do the work for you.

So, here is how to replace a radiator valve:

  1. Shut off your heating system and water supply.

    Turn off everything electrical, turn down the room thermostats, make sure the system won’t start up and nothing is calling for heat.

  2. Locate the drain off.

    Usually, you can find the drain valve at the lowest point in your heating system.

  3. Drain the system.

    Connect a hose to the drain off and secure it with a jubilee clip. Take the other end of the hose outside, where the water can flow into a drain or soil. Put towels down under the drain valve to catch any small spills. Open the bleed valve to let air into the system. This will help the water flow out. Open the drain cock and let the water drain for about 10 minutes, or until your system is completely empty.

  4. Remove the old valve.

    Put towels or a bowl underneath the valve to catch any spills. While holding the valve body with a wrench, undo the top nut, then the bottom one. Remove the valve. Take out the chrome tail, using a hex key or a plumber’s wrench.

  5. Clean the area.

    You can give the area a good wipe at this point with the help of a clean cloth. Clean the threads in the radiator end with wire wool.

  6. Fit the new valve on the radiator.

    Wrap PTFE tape around the threaded end of the new chrome tail. This will prevent any leaks. Screw the tail into the radiator, then slide on the nut and olive. Attach the nut and olive to the water pipe. Connect the new valve body to the water pipe, line it up, and attach it to the chrome tail. Tighten the nut on the tail, then do the same for the one on the water pipe.

  7. Attach the valve top.

    Unscrew the protective cap from the top of the valve body. Connect the valve top to the body and lightly tighten the nut.

  8. Close the open valves.

    Close any open valves, including the bleed valve and drain off. When turning off the lockshield, remember how many turns it takes to close. When you open it back up, you’ll need to make the same number of turns.

  9. Turn the water back on.

    Turn the water on to refill the system. Look out for any leaks from the new valve. When the system is refilled, open the new valve so that water flows into the radiator. Keep looking out for leaks.

  10. Bleed the radiator.

    To learn how to do this, check out our helpful blog post on how to bleed radiators.

  11. Open the lockshield valve.

    Noting how many turns it will take, turn the lockshield valve back on.

  12. Turn the heating system back on.

    Switch the power of your boiler back on. Let it run for a few hours and check again if everything is working properly. Bleed and drain valves need to be turned off, the radiator should be bled, and there should be no leaks.

And there you have it! A comprehensive guide on how to change a radiator valve. You should find this information helpful whether you need to switch a manual or a thermostatic valve.

Do you have to drain the system to change a radiator valve?

While there are ways to isolate the radiator or freeze the pipe, it is always recommended that you drain the system before attempting to do any work on it. If you are unsure if you can do this by yourself, always call a Gas Safe registered engineer to help.

Not sure you can manage this yourself?

If you aren’t certain you can handle this task by yourself, or if you have a conventional heating system, it is always better to rely on professionals. The reliable, experienced plumbers at Fantastic Services can help you out! From changing your radiator valves to boiler installation and repair, they can handle it all!

Simply book online using our form and choose a time that suits your schedule. Spend your time where it matters, let Fantastic Services handle the rest!

Need a plumber?

Find a professional to tackle the hard work for you.

Add a valid postcode e.g. SE1 2TH


  • Drain the system before attempting any work on your radiators.
  • Be prepared to catch any spills by placing towels or a washing up bowl underneath the valves.
  • Always make sure your heating system and water supply have been turned off before changing a radiator valve.
  • Open the bleed valve when draining the system to help the water flow out.
  • When turning off the lockshield, remember how many times you need to turn it, as you will need to do the same amount of turns to open it later on.
  • If you are unsure at any point, call a Gas Safe registered engineer to handle the work.


Did you find this post helpful? Do you have any experience with changing radiator valves? Let us know in the comments below!

Image source: shutterstock / IAS75

5 1 vote
Article Rating
Notify of
Inline Feedbacks
View all comments
Would love your thoughts, please comment.x