How to Fit and Change a Radiator


Learning how to change a radiator makes the process of upgrading your home's central heating system much easier. Choosing to replace a radiator ensures your home is effectively heated and can reduce your energy bills.

Within this guide, we'll talk you through step by step how to fit a new radiator and how to change radiators safely. If replacing radiators isn't for you, a plumber will be more than happy to help!

Things you need to know before you start

There are a few things you need to know before changing or replacing a radiator. Once you've found the perfect radiator for your home, ensure you measure the replacement radiator correctly. Use the pipe centre number which shows the distance between the valves at either end of the radiator connected to the pipework.

Remember to measure depth as it could be difficult to connect existing pipework if your new radiator sits closer or further away from the wall. The height of your replacement radiators shouldn't have any impact as long as the wall is strong enough to support the weight.

Modern Radiator In Bathroom

Can you remove and replace radiators yourself?

If your radiator has identical pipe centres, it's easy to remove and replace the radiator yourself. If this is not the case, you'll need to change the position of the valves, which requires a plumber.

You should also be aware that you could find yourself with water damage to walls and floors if anything goes wrong.

Is it easy to install a new radiator?

Fitting a new radiator like for like is easy to do, as long as the radiators you are replacing have identical pipe centres. It shouldn't take long to do, and you might not need a plumber.

However, if you fit a new radiator that isn't the same size, you'll need to call a plumber. There is a chance adjustments will need to be made to your pipework to ensure everything fits correctly.

Do you need to turn the water off to change a radiator?

Before you start replacing a radiator, you must switch off your central heating system and allow it to cool down. After this, shut off the radiators and bleed out any water from the radiator before removing it.

To do this, close and turn off the radiator valves at either end. At one end is the lockshield valve, which controls the system flow. Remove the protective cap and turn this clockwise to close it.

The other is the manual control valve which turns the heat on or off. Rotate the valve clockwise to shut this off. You may have a thermostatic radiator valve (TRV) instead. If you do, turn the valve to the off position or past zero.

The tools and materials you'll need for the job

Tools Needed For Radiator Fitting

Teaching yourself how to change a radiator is a valuable skill to have. There are a few tools and materials that you need to find before you start installing a new radiator:

  • New radiator and fixing kit
  • Adjustable spanner x2
  • Radiator bleed key (flat-head screwdriver is an alternative)
  • Bucket
  • Cup or small container (for bleeding)
  • Pipe cable
  • Multi-purpose digital detector
  • Large allen key
  • Drill driver (internal walls) or hammer drill (masonry walls)
  • Masonry drill bit
  • Steel wool
  • PTFE tape (thread seal tape)
  • Cloths or an old rag
  • TRV and lockshield valves

PlumbNation stocks a wide variety of plumbing supplies needed for installing a new radiator.

Things to check before you begin

Before you start to fit your replacement radiator, check the condition of your wall. Look carefully for any signs of crumbling plaster and cracks. If the wall plaster or masonry is damaged, then you'll need to make these repairs first.

It's essential to check whether the wall is a stud wall or a brick wall. The tools you need for replacing a radiator depends on the wall type.

You also need to know where your water pipes, wall studs and wiring are. It's best to use a digital detector to locate any wires or pipes to prevent unwanted damage.

6 simple steps to changing your radiator

Follow our simple 6 step guide on how to replace a radiator below:

Step 1 - Isolate the radiator

Firstly, you need to isolate the radiator. Turn off your central heating system and water supply before you start any work. Give the system time to cool down and then close the valves off. There are different radiator valves, so make sure you take the proper steps for your valves.

To switch off a manual valve, turn clockwise until it no longer turns. You may have a thermostatic valve instead. In this case, turn the valve to off or zero.

For lockshield valves, take the plastic cap off and use an adjustable spanner to turn the square shaft clockwise. Remember to note the number of turns so you can fit your new radiator to the same flow rate.

Step 2 - Drain the radiator

Once you've isolated your radiator, it's time to drain it. Find the connection you need at both ends of the radiator. Place a small bowl or tub underneath to collect any water.

Use one adjustable spanner to turn and loosen the nut. You might need your second spanner to hold the valve body in place to prevent pipework from bending or buckling.

Next, you need to bleed the radiator by letting in air. Use a radiator key or screwdriver to loosen the bleed valve cap nuts at the top. Turning this clockwise should release water into the bowl.

If the bowl is filling up quickly, close the top valve and empty the bowl or have another bowl ready to use.

Once all the water has drained, repeat the step on the other side of the radiator. Have some old towels or rags on hand to wipe away any spillages.

Step 3 - Remove the radiator

Remove your radiator by lifting it off the old brackets or the floor. Be careful as you may need to pull the pipes at the sides of the radiator out slightly before lifting. Radiators can be heavy, so it might be good to get some help.

There will likely be remaining water to empty. Tilt the radiator to remove the water and place tissue or an old rag into the outlet at one end to stop any leaks.

It's worth removing the valve tails from your old radiator as you'll be able to reuse these. Use wire wool to clean them and PTFE tape to keep the seal intact.

Step 4 - Replace the wall brackets

Your old radiator brackets will probably need replacing. Unscrew the existing brackets from the wall and fill any gaps left from the previous fixing holes. You need to measure the distance between the fixtures as well as the bottom of the radiator and base of the bracket.

Before you drill, use a multi-purpose detector to check for pipes, wiring and wall studs. After this, mark on the wall where the new brackets need to go and fit them.

Step 5 - Hang the new radiator into place

The next step in replacing your radiator is to fit it into place. Make sure everything is in alignment and put the bleed valves and valve tails into the radiator.

Hang your radiator to the new radiator brackets and connect this to the pipework by tightening the nuts. Usually, this is a job for two people.

Step 6 - Close the bleed valve & reconnect the water

Open up the isolated manual or thermostatic valve and slightly open the bleed valve to let out any trapped air. Once you've finished letting any air out, ensure the radiator bleed valve is correctly closed.

As your radiator fills up, you should hear gurgling. If you don't, double-check the valves to make sure they're open enough. Open the lockshield valve once the radiator is full or has stopped making a gurgling noise.

Check over the radiator for any leaks before and after you switch your central heating system back on. You also need to feel for any uneven heat distribution across the radiator.

If everything is fixed and there are no leaks, turn on your central heating. For homes with a combi boiler, you might need to check the pressure and adjust accordingly.

If you need any further advice on how to remove a radiator safely, read our other guides.