radiator replaced

How to Replace a Radiator Easily Like a Pro


Knowing how to replace a radiator is a skill that can save you a lot of money.

Being a heating engineer, I have replaced a fair few radiators in over ten years of plumbing.

What I can tell you from all those radiator replacement jobs is that every job is different – some are very easy, some are very hard.

Whether you need to how to remove a radiator for decorating, or how to replace a radiator valve, I can teach you.

How to Replace a Radiator – the Easiest Way

If you want to know how to replace a radiator the easiest way possible, then buying the exact same radiator is the way to go.

The same make, the same model, the same size.

This way, you can use the same radiator brackets that are already fitted to your wall for the old radiator.

Just remove the old radiator and hang the new one straight on.

How to Remove a Radiator Without Draining the System

  1. Close the radiator valves on the radiator.
  2. Place some old towels under the radiator valves to catch the dirty water.
  3. Crack the nuts with an adjustable spanner in between the radiator and radiator valves.
  4. Let the water drop on to the towels until it stops coming out. If it doesn’t stop coming out, you will need to drain the system.
  5. Pull the valves off the radiator and place your thumbs over the tails to stop the water coming out of the radiator. If you can’t reach both tails, you will need someone to help.
  6. Then remove the radiator by lifting it off the brackets and empty the water down the drain or toilet.

If you managed to buy the exact same radiator to replace, then you need to fit new radiator valve tails. Or use the old ones from the old radiator. Then:

  • Hang the new radiator on the old brackets
  • Connect old valves on to new radiator tails
  • Open both radiator valves
  • Bleed the radiator
  • Top the pressure up

This is the easiest way to change a radiator or remove a radiator for decorating if you are refitting the old one.

Replacing a Different Radiator

Replacing a radiator with a different radiator is much more difficult.

You will have to fit the new brackets for the new radiator, which will always be in a slightly different place.

Yeah, it’s only a few screws, but it’s getting the correct height measurements to fit the old pipes that is the tricky part.

Imperial vs Metric Radiators

Old imperial radiators are measured in inches, new radiators are measured in metric millimetres.

It’s very common to replace an imperial radiator with a metric radiator.

The problem with this is you can’t get the same size radiator. You will have to buy a metric one that is slightly shorter or slightly longer.

Height doesn’t really matter, it’s all about the length.

I always go slightly smaller. This way I can use longer radiator valve tails.

You can get them 100mm long and cut them down with a standard pipe slice to the length you need.

This won’t always be possible because of larger size differences, you might need to adapt the old radiator pipes to fit the new radiator.

How to Replace a Different Radiator

You can stand the radiator in place to mark the wall with a pencil where the brackets will go vertically, but for the height measurement, you will need to take some measurements.

First, measure the height from floor to the centre radiator valve pipe hole.

Then, measure from the bottom of the fixed bracket on the radiator, to the centre of the radiator valve hole on the radiator.

Add these two measurements together, and then mark the wall in line with one of the other pencil marks you made.

You should mark it horizontally, a good 40mm or so.

This is where the bottom of the radiator bracket will sit, not the bracket that gets fixed to the wall, but the bottom one on the radiator.


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