Category - Boilers
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Will Scholfield, Engineer

31 Jan : Updated 19 Apr ● 9 min read

Radiator valves explained: Types and uses

When it comes to radiators, valves are the vital components that allow your home to heat up effectively and quickly. With a range of radiator types, there are a few factors to consider. So, it's important to do your research to understand what it is you’re buying. 

In this guide, we’ll explain everything you need to know, from how radiator valves work to the different types you’re likely to come across.

What do radiator valves do?

Each radiator in your home uses radiator valves to control how much heat it emits. It is common to use a thermostat to control the central heating around your home, but radiator valves determine how much heat a single radiator releases.

Radiator valves vary significantly, and the type of radiator valves you have in your home will likely differ depending on how recently they were changed.

From manual to smart thermostatic, we'll take a closer look at the different types of radiator valves you could have in your home.

The most common types of radiator valves

When purchasing a radiator, it’s easy to overlook the importance of radiator valves. The wrong valve could lead to an ineffective radiator. A valve that fits appropriately is required to get the most out of your central heating system.

Read on to find out the three main types of radiator valves:

Thermostatic radiator valves

What is a thermostatic radiator valve?

Thermostatic radiator valves (also known as TRVs) provide an easy and inexpensive way to control the temperature of individual rooms around your home. When used correctly, these radiator valves can help reduce the energy and heat you use. This efficiency will help you to save money on your energy bills in the long run.

Looking for more informatio­n on thermostat­ic radiator valves?



Check out our complete guide to thermostat­ic radiator valves which answers what they are, how they work and how they benefit the home.

Thermostat­ic radiator valves guide

How do thermostatic radiator valves work?

Thermostatic radiator valves consist of two different parts: the head and the body. They can change the flow of water when the temperature reaches a certain point, preventing your radiators from getting any hotter. To do this, the head of the valve expands, moving a pin to open and close the valve's body.

If the room becomes too hot, the valve will close, slowing the water movement to the radiator. If a room becomes too cold, the valve will open to allow more water to flow through.

Each radiator with a thermostatic valve can be amended individually. That’s why if you prefer a lower temperature in a certain room, changing it is easy. Simply turn the dial on the valve head (usually found on the side of your radiator) to your desired setting.

Advantages of thermostatic radiator valves

  • An environmentally friendly option compared to other radiator valve types
  • An easy solution for controlling the temperature in each room
  • Helps to save money on your heating bills by reducing heat in rooms that don't need it

Disadvantages of thermostatic radiator valves

  • Thermostatic radiator valves can be expensive to buy, but can save money in the long run
  • These valves can get stuck in a certain position which means the valve won’t be able to open or close (depending on the temperature)
  • A thermostatic radiator valve isn't recommended in bathrooms as the humidity can cause false readings
  • They also aren't recommended in rooms with wall thermostats

Manual radiator valves

What is a manual radiator valve?

Manual radiator valves are angled taps that you can find at the side of your radiator to turn the radiator off and on.
The manual radiator valve is possibly the most simple to operate as well as being the most common type. Depending on how warm or cool you require your room to be, you can easily turn them up and down.

How do manual radiator valves work?

Think of manual radiator valves like taps: turn the head anti-clockwise to turn it on and clockwise to turn it off. This adjusts the amount of hot water flowing through the radiator, which dictates how much heat is emitted into the room.

Advantages of manual radiator valves

  • Manual radiator valves are the most common type of radiator valve, making them easy to find
  • There are plenty of styles and colours to choose from
  • Controlling your heating is simple and easy but does need to be done manually
  • These radiator valves are cheaper than others

Disadvantages of manual radiator valves

  • Manual radiator valves make it more difficult to control the room temperature as you simply turn the head up or down
  • These radiator valves don't come with any automation, so won't adjust the temperature according to the readings

Smart thermostatic radiator valves

What is a smart radiator valve?

Smart thermostatic radiator valves are similar to thermostatic radiator valves as they allow you to control the temperature of each room. However, smart radiator valves take it one step further: they allow exact temperature control of every radiator in your home straight from an app on your smartphone.

To find out what to set the temperature to in each room of your house, our guide on the ideal room temperature in the UK should help.

How do smart radiator valves work?

Smart or wireless radiator valves work alongside a smart thermostat to control your home's temperature. The smart thermostat connects to a Wi-Fi signal. This enables you to control the temperatures of your radiators from a mobile or tablet device.

Unlike a standard thermostatic radiator valve, where you simply turn the dial to your desired setting, smart radiator valves allow you to choose an exact desired temperature, even when you're away from home. Thanks to an app, you’ll have ultimate control of your heating wherever you are. 

Advantages of smart radiator valves

  • You can set the temperature in degrees celsius or Fahrenheit, which is much easier than the scale on a thermostatic radiator valve
  • Monitor your energy use in the app
  • Change the settings remotely, whether you're at home or not

Disadvantages of smart radiator valves

  • SRVs are costly, usually between £35 and £80 each
  • SRVs require a compatible smart thermostat for full functionality
  • You have to stick to one brand as most SRVs are only compatible with that manufacturer's thermostat and connecting device

Types of radiator valve fittings

With lots of different types of radiator valve fittings, it's easy to get confused with which your radiator requires. We've created an overview of some of the most popular radiator valve fittings to help you figure out which your radiator needs.

Lockshield radiator valves

Lockshield radiator valves are covered radiator valves, usually at the side of a radiator. They're covered with a plastic cap to prevent accidental alterations. Every radiator has one, as they're an essential component of your central heating system.

This type of valve fitting controls how much water can exit the radiator. Once installed, you shouldn't need to adjust the lockshield valve unless your radiator takes too long to warm up. If required, simply turn the spindle to open the lockshield and allow a greater flow of hot water through the radiator.

Angled radiator valves

Angled radiator valves are placed at a right angle (90°) and are one of the most common valve shapes. They're particularly handy for homes with concealed pipework.

Corner radiator valves

A corner valve helps to save space. They work similarly to angled radiator valves but can be a little fiddly to adjust.

Straight radiator valves

Straight valves are ideal if your pipe runs straight along the wall to the valve. This is commonly used for heated towel rails.

H-block or twin valves

H-block vales have a double connection to allow the water inlet and outlet to be located in just one valve to ensure that hot water flow is consistent around the radiator.

Which size radiator valve do I need?

If you're trying to figure out which size radiator valve you require, it's important to remember that it’s not necessarily the size of the valve itself but rather the size of the connection to the pipework. Of course, if you’re short on space surrounding your radiator, the valve size may be something you do consider.

Pipework for radiators can sometimes vary from 8 mm to 28 mm. The most common size is usually 15 mm. Valves tend to be manufactured to fit this specific size, but variation can occur. It’s unlikely that you’ll find an 8 or 10 mm radiator valve - but adapters are available if you struggle to find the appropriate size.

Do you have a room with a specific theme? Don’t want the radiator to ruin the aesthetic? That’s not a problem. As well as size, there is also an array of alternative valve styles available for purchase. Choose from brass, chrome, or even more traditional styles. They're all fairly simple to install and replace.

How to fit a radiator valve

If you have a standard boiler system, you’ll need to seek the help of a registered professional before fitting radiator valves. To fit or change a radiator valve, you must follow several steps to ensure it’s successful:

Step 1: Switch off your heating system and shut off the water

Before you change the radiator valve, you'll need to switch off the heating system and water supply. This means that water can no longer enter the boiler. Without doing this, the boiler could overheat.

Step 2: Locate the drain-off valve

Once complete, you'll need to drain your central heating system. Locate the drain-off valve. Connect a hose to the drain-off valve and position the other end of the hose to allow water to run into an outside drain.

You’ll then need to wait for the water to drain completely from your radiator. This can take up to 10 minutes.

Step 3: Remove the old radiator valve

To do this, undo the top nut on the existing valve and then spin the bottom nut. This will allow you to remove the valve entirely. Water can sometimes run out at this point, so have a towel ready.

Step 4: Fit the new radiator valve

Fitting the new radiator valve will vary depending on the fitting and type you're installing. Because of this, it's best practice to follow the manufacturer's guidelines on how to fit the radiator valve.

Step 5: Turn on the water mains

Once you've installed your new radiator valve and tightened everything up, it's time to turn the water mains back on. This will refill the system, so keep an eye out for leaks at the new joints. Once refilled, open the new valve to allow water to flow into the radiator.

Step 6: Bleed the radiator

Once you're happy there are no leaks, open the bleed valve to let out any trapped air. Trapped air can prevent the radiator from filling with water, so this is an important step to get the most out of your heating system.

If you're stuck on how to bleed a radiator, we've created a simple guide to take you through every step.

Step 7: Turn on the boiler

Get your boiler back up and running again. Once your heating system has had time to warm up, look at the radiator one last time to ensure there are no leaks and that the radiator is working as it should.

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