How To Change Radiator Valves

Nothing is forever and that unfortunately includes everything from youth, to radiator valves. There could be any number of reasons why you might need to replace your homes radiator valves. But how exactly do you go about this process? 

It’s a quiet involved process but we will take you through it step by step and help you double-check everything is done correctly too. You will need around 15 minutes to replace one radiator or attach the new one.

Why would you need to change a radiator valve?

There could be several reasons for the need to arise. For example, your radiator valve could have simply stopped working and may be leaking. Or maybe, you want to replace one type of valve with another. Moreover, the case could also be that of your old valves don’t fit the modern aesthetic.

Regardless of the reason, this article will help you switch your radiator valves in the minimum number of steps and with the minimum fuss. You will learn how to change a radiator valve and about draining out the system.

As with any other plumbing activity, you must have essential prior experience or knowledge before diving into it. In case of lack of either, you should have a professional help you out.

There could also be a difference in your situation regarding how and which valves need replacing. Some complications could enter the picture in the way these valves are connected as well. 

Some valves are connected to pipes that shoot down into the floor, whilst others will be connected to pipes that jut out of the wall.

How do radiator valves work? 

There are three main types of radiator valve out there. So, to figure out which system would be ideal for you, you must be familiar with both.

  • TRV
  • Manual
  • Lockshield

Thermostatic radiator valve (TRV)

You might have heard people refer to thermostatic radiator valves as TRV as well. The system offers you a unique temperature sensor. The specialty lies in how it automatically turns off your heating on reaching the desired temperature. It can also switch back on to keep a nice stable temperature throughout your house. 

This ensures not just an accurate temperature but also keeps the system constant. The metal spring will expand if the room is hot, thereby stopping the flow of hot water. And similarly when the room is cold, it contracts and reopens the valve allowing hot water to flow through the radiator again. 

A thermostatic radiator valve system can save you a substantial amount each year in your heating costs and shouldn’t be overlooked if you are planning a new home heating system. 

TRV valves are more expensive so if you are updating your system, it’s a good idea to keep one valve as manual. This will help you keep the flow of central heating constant and also save a bit. 

Jammed radiator valve

The most common type of problem you might experience with TRVs is when the head of the valve begins to stick or jam. This renders the heating system useless and you cold. You might experience this issue at the end of the summer or when retuning from holiday, as an unused system is prone to jamming.

You can begin by checking out the pin after unscrewing your TRV’s head. Check if the pin is standing out from the valve’s body. If the pin is lodged inside the valve, then spraying some oil on it should be sufficient. 

Additionally, you could also try a using a pliers to dislodge the pin.  However, if the pin is stuck further inside try tapping the valve gently around its outside edges. It should work wonders if you find the right spot around the pin. Do not whack it, gentle taps will do the trick!

If things are still not looking good it might mean that the pin is stuck deep in the valve. Try tapping carefully on the exact location of the pin. The motion should be gentle but forceful enough for the pin to come. Use WD40 or other oil to help

Lastly, if nothing seems to be working on the new valve, know that the pin might not even be the problem. The liquid capsule or wax that is present in the head could have failed. In this case, knowing how to change a radiator valve might not be of much use. You might have to buy a fresh piece of TRV valve.

Leaky thermostatic radiator valve

In case of leaky thermostatic radiator valves, you can use some plumber’s tape. People also refer to it as PTFE tape and you can pick it up in any hardware store and many of the bogger supermarkets too. 

Firstly you must turn off the TRV and lockshield valve, thereby isolating the radiator. The chances are, that your leak could be coming from one of these two areas. Even though it sounds complicated, look at the radiator’s side, which you can easily loosen. Then, with the olive to you a piece of your PTFE tape. The olive is the beveled-ring-like-looking compression.

In case it is the thread on the insert that keeps leaking, you could try slackening it. Expose as much length as you deem fit. Next, try winding your PTFE tape in the direction of the slackening. You could further rewind it, thereby tightening the nut and its olive. 

Finally, you could run the new valve to check if the leaking has stopped or not. Further, clean the area.

Manual radiator valve

Manual valves are the most common in the UK and work pretty much like a regular tap. As you turn the valve, you allow the hot water to flow through the radiator. When you close the valve, you stop that flow and the radiator will cool. Due to the need for manual management of the heating, it can be costly and you may find yourself unnecessarily heating areas of your home that don’t need it.

If you have a problem with this type of valve, here is how to fix it.

Leaky manual valve

The most common problem with manual valves are leaky glands. If you are unsure what a gland is, it’s the point where the spindle passes through to the remainder of the body of the valve.

The primary purpose of the gland is to prevent water from leaking out the top of the spindle. It is compressed by a cap nut which is the highest nut that you will find on the spindle. 

If you see a leak here, first try to tighten the cap nut. This will compress the packing, thereby ceasing the water from leaking. However, do not go way overboard with it. Increasing the compression on the packing can lead to the spindle sticking and making it difficult to turn the radiator on and off.

Another possible issue is a worn out ‘O’ ring. Some types of manual valves use this ‘O’ ring to make a seal and over time and with use, these wear out. A quick fix can be turning the valve completely on or completely off. But you’ll need to replace the ‘O’ ring.

Lockshield valve

Unlike the previous types, you will find that a lock-shield valve is layered over with a cap made of plastic. What’s more, the word lock-shield refers to this plastic cap that helps shield it.

By removing this plastic cap, you will get a clear view of the spindle. You can adjust or turn this with a spanner and control the flow of water that passes through the valve.

Usually, you’ll only need to adjust the lockshield valve when you are balancing your radiators.

Leaky lockshield valve 

If you adjust the lock-shield valve by balancing the radiator, the water will heat up in just as much time. Since the problem is quite similar to the manual valve issue, you could follow the same procedure. Make sure that the PTFE tape is of good quality and you are all set.

What do I need to replace a damaged radiator valve?

Here are many things that you will need as you learn how to change a radiator valve. 

  • A towel or a dry cloth
  • Hose
  • Jubilee clip and a hex key
  • Plumber’s wrench
  • Adjustable spanner
  • The new valve you intend to fix. 
  • PTFE to tape around the radiators
  • Wire wool
  • Freezing kit: in case you want to avoid draining the system 

Changing your radiator valves

If you have a conventional or heat only boiler, this process will not work for you and you should contact a heating engineer.

This method is ideal for combi boiler systems though and remember that whilst it is possible to do this yourself, if you don’t have the tools or have limited experience, it’s probably best to call a professional heating engineer.

Here are six steps on how to change your radiator, or add a new one.

Step 1. Switch off the heating system and water

Because we will be cutting off the water flow, the first and most important thing to do is turn of the boiler. It’s essential to avoid damaging the heating system and can be seen as a measure to avoid the pumps from burning out too.

Make sure to;

  • Turn off the electricity supply. 
  • Turn off your room thermostats
  • Ensure that all the heat commands are turned off

Step 2. Drain The System

The drain off can usually be found at the lowest point of pipework in the house .You will need to use a hose to connect the drain off to somewhere outside to get rid of the water. Somewhere in your garden or an outside drain will do. 

Then, release the drain cock and empty the radiator before changing it. At this point, you will need a jubilee clip to hold the hose in place and prevent the chances of any spills.

Wait until it is completely drained of all the water. Depending on the type and condition of your radiator, this could take anywhere from 5  to 15 minutes.

Step 3. Removing The Old Radiator Valve

This part is easy, remove the nut at the top first and then the lower one allowing you to completely take off the valve. A decent wrench will come in handy to hold the valve body and you should expect some run off from the system so be ready with a cloth or painting tray to collect any dripping water.

Use the wire wool to clean the around the radiator valve

Step 4. Fit The New Radiator Valve

Try to situate the new radiator tail in place of the old one. Use the plumber’s tape to minimize any risk of leakage. Then, slide the nut into the radiator tail along with the olive. 

After you identify the water pipe, try to slide the nut. Next attach the olive. The equipment is now ready for you to place the new radiator valve in it. Connect its body to the water pipe as you insert it into the radiator tail. 

It would be best if you were careful here because misplacement can lead to a damaged new valve. Then, connect the upper body of the valve to its lower half and tighten the nut. Again, over-tightening could lead to distortion, and you want to avoid that to the best of your capacity. 

Step 5. Turn the mains water back on

Now you need to seal and close the radiator valve that you opened. Chances are, there are more than one valve, so begin from the top. 

After turning off your lock-shield, make sure that you close it in the same amount. In any case, otherwise, you could end up with distortions or damage. 

Remember to turn on the water again, thereby refilling your system. This time, you need to keep an eye out to double-check for leakage problems near the joints. 

Step 6. Bleed the radiator

Did you make sure that none of your radiator valves were showing signs of leakage? Now it is time to release any trapped air by opening up your bleed valve. The radiator bleed key will come in handy here. If you do not carry out this process, the air will keep the water from entering and filling the system. 

  • Drain off valves, and ensure that they are turned off.
  • Ensure that the air cocks and valves are turned off as well. 
  • And you will need to turn on the water mains again.
  • Next, you will have to bleed the radiators and check if the joints are showing leakage problems or not.

Radiator Valve Replacement Tips

Without a doubt, prevention is always better than cure. While you know how to change a radiator valve, here are a couple of ways to keep them clean. 

Firstly, you should check if you have left the radiator bleed key sealed or not. Next, ensure the use of extra equipment such as a dry cloth, towels, or a bowl to catch drips. The last thing you want is your floor and clothes to be spoiled with leakage. 

That said, always prepare yourself, assuming that there could be a spillage. After all, it is better to be over-prepared than under-prepared.

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Last Updated on May 3, 2021


Author: Indra Gupta

Indra is an in-house writer with a love of Newcastle United and all things sustainable.

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