How To Install a Radiator Valve

Updated: September 1, 2023

When it comes to installing a radiator, you're going to need to also install a radiator valve. However, changing radiator valves on existing radiators is a task that can greatly improve the efficiency and functionality of your heating system.

Whether you have a leaking radiator valve, your radiator valve is stuck or you're simply looking to fit a thermostatic radiator valve to benefit from efficiency improvements, this step-by-step guide will walk you through the process of changing a radiator valve, ensuring that your home stays cosy and energy-efficient.

Anatomy of a Radiator Valve

Let's get started by understanding the components of a Thermostatic Radiator Valve. If you have a Manual Radiator Valve, don't worry, all the essential parts are the same. The only difference will be that you won't have the "Thermostatic Head".

Diagram showing the anatomy of a Thermostatic Radiator Valve

The bits that you are going to want to take note of are the:

  • Securing Ring
  • Radiator Tail
  • Radiator Tail Nut
  • Compression Connection

These are all of the parts that usually need assembling.

Tools That You Will Need

Before you begin, gather the necessary tools and materials:

  • Two/Four large buckets
  • Plenty of towels or rags
  • Waterproof/Plastic sheet (if you have carpets)
  • Flat head screwdriver
  • Small length of hose
  • Jubilee Clip
  • Adjustable wrench
  • Pipe wrench
  • Replacement radiator valve
  • PTFE tape
  • Pipe cutter (if necessary)
  • Pliers

Step by Step Guide

1. Turn Off the Heating System

Start by turning off your heating system. This is crucial to avoid hot water or steam flowing through the radiator while you're working on it, preventing any accidents or burns. If you've recently had it on, wait for it to cool down. Check if the radiator, and the pipework around it, that you're about to work on is cold.

2. Gather Your Tools and Materials

Make sure you have all the tools and materials listed above within arm's reach before you begin.

3. Drain the Radiator

Cover as much of the floor beneath the radiator as possible with your waterproof sheet (if you need it) and towels to catch any spills.

If you can isolate your radiator, then do this now. Locate your isolating valves and using your hands or your flathead screwdriver, close the valves. If you don't have this option, unfortunately, you are going to have to drain your entire system. Find the lowest drain-off valve and follow the next paragraph.

If you have a drain-off valve for your radiator, then attach your length of hose to the drain valve and secure it with the Jubilee Clip. Point the hose into your bucket and carefully open the valve to drain the radiator. When there is no more water draining out, close the valve and come back to your radiator.

The final step is to place a bucket underneath each of the radiator valves you want to remove. Keep other buckets very close by, ready to replace when they fill up.

If you've been able to do all of the above, then that's great. If not, then make sure your buckets are secure and ready. You're about to have a much messier experience.

Now follow the next step.

4. Loosen the Radiator Tail Nut

Making sure you have buckets under your radiator valve to catch any remaining water, turn the Radiator Tail Nut anticlockwise to loosen the connection.

If there is water draining out, then let this happen. Don't move to the next step until there is no significant flow.

5. Completely disconnect the Radiator Valve.

Continue turning this nut anticlockwise to disconnect the Valve from the radiator. Then follow suit with the Compression Connection.

6. Prepare the New Valve

Wrap the threads of the new valve with PTFE tape to ensure a watertight seal. Make sure to wrap the tape in the direction of the threads to prevent unravelling.

More is better here. You need to make a good seal.

7. Attach the New Valve

Put the Radiator Tail inside the new Radiator Tail Nut and carefully screw the Radiator Tail into the radiator threaded connection. Use an adjustable wrench to tighten the screw, ensuring a snug fit. Be cautious not to over-tighten, as this could damage the threads.

Then screw the Radiator Tail Nut onto the valve to complete the connection. Again, you can tighten this for a snug fit, but don't over-tighten.

8. Reconnect the Pipes

Connect the Valve back to the central heating pipework via the Compression connection. You can learn more about this process in our blog: How to install Compression Fittings.

9. Turn On the Heating System

Once you've securely attached the new valve and reconnected the pipes, keeping your towels on the floor and open your isolation valves (if appropriate). You will need to re-fill your central heating system using the filling loop on the boiler. When it's at pressure, turn on your heating system.

Carefully check for any leaks around the valve and pipes. If you spot any leaks, tighten the connections further. If you can't do that, you will have to restart the entire process to apply more PTFE tape.

10. Bleed the Radiator

After turning on the heating system, air may have accumulated in the radiator. Use a radiator key to bleed the radiator and release any trapped air. Open the bleed valve until water starts to flow consistently.

11. Check for Leaks

Double-check all connections for leaks and drips. If you notice any leaks, address them promptly by tightening the connections or restarting this process to apply more PTFE tape.

Wrapping Up Changing A Radiator Valve

It may seem like a daunting task, but with the right tools and a clear understanding of the steps involved, it is a very manageable DIY job. By following this step-by-step guide, you can ensure that your home heating system remains efficient, reliable, and comfortable, all while potentially reducing your energy consumption and bills. If you're unsure about any step or encounter unexpected challenges, you can always call in a professional plumber to help.

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