Replacing a radiator: How to Change a Radiator

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.

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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, you can do the job without draining the system.

Removing the old Radiator

Refer to our removing a radiator project for instructions on removing the radiator.

Replacing the Radiator

An example of a single panel convector radiator available from ScrewfixIf 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 etc and fit them to the new radiator.

Make sure the old radiator is empty of water, 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.

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.

Make sure the new radiator fits onto the brackets for the old one, or replace the brackets with new ones if necessary. Hang your radiator on the brackets, then connect the valves back into the adapters. 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.

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. 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 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.

Screw the top 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.

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.An example of a Pipe Cutter available from Screwfix

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. Use a heat-proof soldering mat to make sure any other pipes nearby, and any wooden floorboards or joists, are protected. 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.

Hang the new radiator and attach the valves. Refill the heating system, and check all of your new joints to make sure there are no leaks.


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