Radiator Installation

Contents:

• Tools & materials
• Step-by-step
• Common mistakes
• How to move a radiator
• How to change radiator valves
• FAQs

Well fitted, good quality modern radiators keep rooms warm and they work efficiently to save you money on your energy bills. If any of your radiators are worn out or aren’t working properly, it might be a good idea to replace them.  

In this guide, we’ll give you step-by-step instructions for how to replace a radiator. We’ll also answer some of the common questions about radiator installation.

Installing a radiator is a job you can do at home if you have some basic plumbing experience and reasonable general DIY abilities. You also need to have a few tools, including a power drill and a small selection of plumbing tools.

Here are all the tools and materials you need to change a radiator:

• New radiator (with wall mount and fixings)

• Adjustable wrench or waterpump pliers x 2 – for shutting off and disconnecting your radiator.

• Lockshield valve key (optional) – for shutting off the lockshield valve.

• Radiator key – for emptying your old radiator and bleeding your new one.

• PTFE tape – for creating watertight connections.

• Flat head screwdriver – sometimes you need a flathead screwdriver to take the cap off the lockshield valve.

• Radiator draining kit – for collecting the water when you empty your radiator and for catching spilled water.

• Measuring and marking equipment (including a spirit level) – for fitting your new radiator mounts

• Power drill – for attaching your new radiator mounts to the wall.

Check the size of your new radiator

When you're picking your new radiator, think carefully about the size.

The easiest thing is if your new radiator fits in exactly with the location of the pipes for the old one. This way, you can swap the radiator without needing to change the position of the pipes. If you want to use a radiator with dimensions that don’t match the locations of your pipes, you’ll need to hire a plumber to move the pipes before you can fit your new radiator.

Step 1. Turn off the heating system

Turn off your central heating and let your entire heating system cool down before you do any work. You should also check you know where the shut off valve for your central heating system is in case you have a leak.

 

Step 2. Disconnect the old radiator

The next step is to shut off the radiator valves so you can disconnect the radiator without flooding the room.

At one side, you should have either a manual control valve or a thermostatic valve. To shut off a manual control valve, turn it clockwise until it is completely closed. If you have a thermostatic valve, make sure it’s turned completely off.

At the other end, there will be another valve called a lockshield valve. This controls the amount of water that flows through the radiator. Use an adjustable wrench or a lockshield valve key to turn it clockwise until it’s completely closed. Count the number of turns it takes to close it because you’ll need to open it by the same amount after you fit the new radiator.

 

Step 3. Drain the old radiator

Before you disconnect your old radiator and take it off the wall, you need to drain it.

Place towels around the radiator anywhere water could leak. Then place a large tray underneath the swivel nut next to your manual control or thermostatic valve. This should be ready to catch the water when you drain the radiator. Then use one adjustable wrench to grip the valve while you loosen the swivel nut that connects the valve to the radiator. Completely disconnect it from the radiator.

The water won’t rush out until you release the bleed valve at the top of the radiator.

Next, remove the bleed valve cap and use your radiator key to loosen the bleed valve at the top of the radiator. This will break the vacuum inside the radiator so the water flows out and into your tray.

Carefully drain all the water out, making sure you don’t get any on the floor. Often, people keep a bucket handy and move water from the tray to the bucket.

 

Step 4. Remove the old radiator

Once the old radiator is completely drained, you can take it off the wall.

First, loosen and disconnect the swivel nut on the other side of the radiator that connects the lockshield valve to the radiator. Then make sure the pipes are completely disconnected at both ends.

The method for taking the old radiator off the wall will depend on the type of mount used to attach it. Often, you can just lift it off. Make sure, however, to check for the right method for your radiator.

After you’ve removed the old radiator, take the old mounts off the wall as well. This will mean removing the fixings from the wall. You might also need to fill any holes and redecorate the wall.

 

Step 5. Hang the new radiator

The next step to change a radiator is to hang the new radiator on the wall.

First, you’ll need to fit the mounting brackets to the wall. The method for fitting these will depend on the type of radiator you have and the type of wall you're attaching it to. Refer to the instructions that come with your radiator. 

Make sure you follow the right method for the type of wall. Fitting mounts to a stud wall will take a completely different approach to fitting them to a masonry wall. A wall scanner might be useful for detecting wood and metal studs, as well as live electrical wires at this stage.

After the mounts are fitted, attach your new radiator to the mounts.

 

Step 6. Connect the new radiator

Next, you can attach your radiator to your central heating pipes.

Reconnect the swivel nut that connects the manual control or thermostatic valve to the radiator, using PTFE tape to get a watertight connection. Then connect the swivel that connects the lockshield valve to the radiator. Again, use PTFE tape.

You shouldn’t overtighten the connections. Normally, hand tightening the joint and then adding ½ to ¾ of a turn with a wrench is enough.

Next, make sure the bleed valve is correctly installed on the radiator and closed.

After this, you can turn the water to the radiator back on. Reopen the manual control or thermostatic valve on one side of the radiator. Then reopen the lockshield valve on the other side of the radiator.

Remember to open the lockshield valve to the same point as it was originally. Have a careful look for leaks after you turn the water on.

 

Step 7. Bleed the new radiator

The final step in changing a radiator is to bleed the new radiator to get all the air out so it works properly. Learn how to bleed a radiator. After this, you can turn your heating back on.

Be aware that you may need to repressurise your heating system or balance your radiators after you’ve finished. Learn how to balance radiators.

Here are some common mistakes to avoid when you’re replacing a radiator:

• Not turning off the heating before you start

• Spilling dirty radiator water on the floor

• Overtightening connections

• Not properly bleeding the radiator

• Not making sure the system is correctly balanced after installing the new radiator

• Not repressurising the heating system

If you want to fit a new radiator at a new location in your home, this will mean laying new pipe to the location. This is a job that involves using pipe cutters, installing new sections of copper pipe or PEX pipe and adding new pipe fittings. If new pipes need to be installed, we recommend hiring a competent and suitably qualified, registered plumber for this. This will add to the radiator installation cost, but it’s necessary.

If you’re hiring a plumber to help you with the piping, it will normally make sense to ask them to fit the radiator and any radiator accessories as well.

Make sure you discuss the type of radiator you are going to install with your plumber before you install it. You should check it has a high enough BTU rating for the room it will heat. You also need to be careful you don’t install too many radiators for the output of your boiler (measured in kW).

Electric radiators are an alternative to plumbing in a new radiator.

If you want to move a radiator to a new location in your house, this will also mean adapting the pipework. Again, we recommend hiring a competent and suitably qualified, registered plumber for the task. And again, it will normally make sense to ask them to fit the radiator as well as move the pipes.

If you’d like to speed things up and reduce your radiator installation costs, you can remove the old radiator before they come.

Find out the best way to remove a radiator so you minimise damage and ensure optimal functioning post move.

It’s best to leave changing radiator valves to a plumber. Changing the valves means draining the entire system, and this is a job for a suitably qualified professional plumber.

If a valve on a radiator is leaking or malfunctioning, it will need replacing. While this will come with an installation cost, new radiator valves will function better. Smart thermostatic radiator valves, for example, can save you money on your energy bills with a scheduling function or even by detecting open windows. You can also use them to create zoned heating in your home.

While most radiator valves need a professional, you can change radiator bleed valves and caps yourself.

Radiator installation for replacing an old worn out radiator is a job you can do yourself with some basic plumbing and DIY experience. Make sure you get properly prepared, make sure you work carefully as well and make sure you do any follow up work you need to. You might need to repressurise your central heating system, for example.

Find out about radiator selection in the radiator buying guide.