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Removing a Radiator: Do I Drain the Whole System?

By: Chris Hogan MSc - Updated: 2 Apr 2021 | comments*Discuss
Radiator Central Heating Remove Drain


I am taking a radiator off the wall in my kitchen. Will I have to drain the whole system and once it's off the wall will it be OK to just connect the pipe together as if there was no radiator there?

(G.W, 6 May 2009)


The answer to this is yes and no -- but it's all good news – yes you don't have to drain the whole central heating system but no you don’t even have to connect the two pipes together. By closing the valves at both ends you can drain the water out of the radiator then take it away.

Getting Started

Start by getting a bucket or bowl that will fit under the radiator and close the control valve, that's the larger one which might have a thermostatic valve on it. Then do to the other end, closing the smaller valve that's known as the lockshield valve. You'll need to remove the small white cap and get pliers or a small spanner to do this.

It's important to count the number of turns to close the lockshield valve as you'll need to set it back in the same place when you replace the radiator.

Disconnecting the Radiator

Place a number of old towels or dustsheets under the radiator to collect any water spills and put the bowl under the control valve. Then disconnect the union nut (the nut holding the radiator to the control valve) and water will begin to trickle out of the radiator into the bowl.

Once the radiator is fully drained you can undo the union nut at the other end, by the lockshield valve. Opening the bleed screw at the top of the radiator will increase the flow of water out of it. Then stuff paper into each end of the radiator to prevent drips and remove it from the brackets holding it onto the wall.

Replacing the Radiator

To replace the radiator on the wall, hang it on the brackets and reconnect the valves at both ends, cleaning the threads first and using PTFE tape on the threads. Then open the valves to allow water into the radiator, opening the lockshield valve the same number of turns as when you closed it. This will keep it at the same temperature as before.

Undo the bleed screw to allow air to escape fully although be careful to close it before water gushes out. You may have to bleed other radiators nearby if air gets into the pipes from the radiator you emptied. Check for leaks from the valves too.

Doing Away with the Radiator

If you don’t want to replace the radiator you can join the two valves together with a pipe and this is unlikely to harm the central heating system. Air would get into the pipes though and with no bleed valve you would have to chase the air through other radiators.

You will also have to re-balance the system as the removal of one radiator will upset the equilibrium which means that other radiators will be hotter or colder as a result. You must also protect or hide the pipe that has replaced the radiator as it will get very hot. In some way you need to prevent people from being able to touch it.

The correct solution, as you probably already know, is to re-route the pipework to remove the valves and the unused section of the pipe network.

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the rad is empty but scrap what iwant to know is how can you take off fittings without draining system, I did see this done by a heating engineer but forgot how he did it., do very hope you know. many thanks.
cliff - 10-Feb-20 @ 12:01 AM
Hi all, seeking advice on removing a kitchen radiator which has never got warm when system is in operation. The rad is effectively the 'end of the system' before return but as it never gets warm I wish to remove it and then cap off the pipes, hopefully without needing a joining pipe to create the circuit. The rad has been bled of air etc and still nothing happens, the system is fired by a combi bolier (victorian 3 storey house) all other rads work fine.Thanks for any help
Staffie - 9-Oct-19 @ 12:44 PM
After watching several videos and reading articles on sites such as this, I still have a problem: After shutting off control valve and lockshield valve then loosening union nut (and opening bleed valve), I seem to have managed to drain radiator however when I attempt to disconnect union nuts at either end of rad water shoots out of the flow pipe and strangely the same with the return pipe (in both cases water is under pressure not simply leaking back). Any ideas anyone?
Ceedubyapee - 25-Apr-17 @ 4:32 PM
Hi there,just wanted to know do I drain the system if I wanted to move the radiator across the room. Thank You
sagz - 28-May-15 @ 8:29 PM
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