Replacing a Radiator - How to Change a Radiator Like-for-Like and also Replacing a Radiator With one of a Different Size

Summary: Replacing a radiator when decorating or find out how to replace an old radiator with a new radiator. Follow the step by step instructions to changing a radiator over. Learn all about what you need to do to remove a radiator including turning off your heating system and draining a radiator or heating system, how to connect up valves and also how to reconnect a new radiator. Also find out about how to replace a radiator with one of a different size including how to access existing pipework, how to remove valves and valve adapters, how to fit new radiator brackets and how to connect and solder new pipework.

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Sometimes old radiators become corroded and inefficient, or you may want to change a radiator for an attractive designer one. Either way, if you are removing a radiator for decorating then replacing it, or taking out an old radiator and replacing it with a new one, read our guide below.

If you are replacing the radiator with one that’s the same size and dimensions, you can do the job without draining the system.

Removing the old Radiator

We have a very easy to follow project on exactly how to do this job so please refer to our removing a radiator project for full instructions.

Replacing the Radiator

Are you Removing the Radiator for Decorating or Replacing With new?

If you are just removing the radiator for decorating purposes, then you can simply move it out of the way while you decorate, then put it back on when you’re done.

If you are replacing the radiator for one of the same size and style, you should be able to just take the old valves off and fit them to the new radiator. In most cases you will also then want to fill the radiator so you will probably need to top up your system.

Single panel convector radiator

Single panel convector radiator

Empty the Old Radiator Before Removing and Refit Valve Adapters

Make sure the old radiator is empty of water before you remove it (full instructions can be found in this project), and unscrew the valve adapters from the bottom using an adjustable spanner or a specialist radiator spanner.

Clean the threads up with wire wool and wrap some PTFE tape around them four or five times. This will make the joint secure and prevent any leakage. Screw the adapters into the new radiator.

Remove and Refit Blanking Plugs

Use a bleeding key to undo the bleed valve at the top of the old radiator, then use a radiator spanner to undo both blanking plugs. Again, clean the threads with wire wool and wrap with PTFE tape, before screwing them into the new radiator.

Hang the Radiator on Brackets and Reconnect the Valves

Make sure the new radiator fits onto the brackets for the old one, or replace the brackets with new ones if necessary. Once you have decided which you need to do hang your radiator on the brackets

The next job is to connect the valves back into the adapters that you have previously moved over to the new radiator. Ensure that the valve fits flush with the adapter and also fits "square" as if it is at a slight angle you may damage some of the threads when screwing up the adapter nut.

On this note, screw the nut up until it is finger tight. Do not tighten with a spanner until the adapter and nut have been screwed up on the other side also as this will allow for a slight bit of movement. Once both have been screwed up, tighten with a spanner, again being careful not to over-tighten and damage the threads.

Now, open up the valves, fill the radiator and bleed it to make sure no air remains in the system. If you have a combi boiler you may need to check and adjust the pressure after filling the radiator and you may also have to top up the system slightly.

Replacing with a Different Radiator

If you are replacing your radiator with one of a different style or size, you will probably need to drain the system so that you can adjust the pipework.

Drain Down Your Central Heating System

See our central heating draining and removing a radiator projects to get you up to the stage where you can start work on replacing the radiator.

You will need to be confident in soldering pipes to do this job yourself – if you are unsure get a professional plumber in.

Remove the old Brackets

Remove the old brackets from the wall, and lay your new radiator on the floor, face down. Slide one of its brackets into position on the back of the radiator, and measure the position of the brackets.

Transfer your measurements onto the wall, allowing for a clearance of 100-125mm (4-5”) between the bottom of the radiator and the floor.

Hold the bracket up against the wall and mark where you need to drill holes for fixing it. Some radiators come with a template for fixing the brackets, which will make your job a bit easier. Drill and plug the holes, then screw the bracket into place.

Try hanging the radiator on the brackets to make sure it fits well. Additionally, when fitting the brackets use a spirit level to make sure they are level. You don't want a wonky radiator!

Screw in Top Valves and Bottom Valve Adapters

Screw the top valves (normally bleed valves) and bottom valve adapters into the radiator if they are not already fitted, making sure to wrap a few layers of PTFE tape around the threads before you screw them in. Make sure the joints are secure and tight, using an adjustable spanner or radiator spanner.

Access the Existing Pipework

If the pipework is underneath floorboards, take up the floorboard nearest the wall to reveal the pipes. If the floor is screed or concrete there may be a boxed pipe run, which you should be able to remove the top from.

If the pipes come through the wall, you may just have to extend or shorten the pipe run along the wall.

Work out Where Your new Pipes Need to go

Work out where you need to run new pipes, and cut the old pipes wherever necessary, using a pipe cutter. Prepare your new pipe run, making sure your pipe and joints are clean and prepared with flux.

Solder up Pipework

Use a heat-proof soldering mat to make sure any other pipes nearby, and any wooden floorboards or joists, are protected if you are using a blow torch. Use Yorkshire fittings which are pre-prepared with solder in them to make your job easier.

Our project on soldering pipe joints will explain everything. When you are happy that everything is in place and properly prepared, you can solder the joints.

15mm pipe cutter

15mm pipe cutter

Support Pipework With Pipeclips

Once you have connected your pipes up to your radiator and also into the existing pipework you will also have to ensure that it is adequately supported by using pipeclips.

You must ensure that the pipe is suitably supported and no strain is being placed on any joints as this will eventually lead to failure and leaks.

If you are running pipes under floorboards then the chances are that any joists will already be notched and, where possible, you should use any existing notches. PLease avoid created any new ones as each notch will weaken the joist.

Hang the Radiator and Connect the Valves

Hang the new radiator and attach the valves ensuring that they are screwed up tight (but not too tight). Refill the heating system, and check all of your new joints to make sure there are no leaks before you refit any floorboards or boxing.

Don't fancy doing this project yourself? We work with Checkatrade to ensure that we recommend only reliable and trustworthy tradesmen.

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