How to change a radiator valve


Our guide will take you through how to change a radiator valve in just a few, easy steps. If you’re upgrading your standard manual control valve to a Thermostatic Radiator Valve (TRV) to get control more over your energy usage, we have the right tools and products for the job.

To change a radiator valve, you’ll first need to drain the radiator. We’ve covered this in detail in our ‘How to remove a radiator’ guide, but we’ll also run through it in this guide.

What you’ll need

changing a radiator valve

How to change a radiator valve: step-by-step

  1. Lay an old towel underneath the radiator, gathering the ends around the pipes at either side of the radiator, to catch any drips.
  2. To isolate the radiator, turn the manual control valve clockwise until it won’t turn anymore. Then remove the cap and tighten the bolt further with a spanner. Remove the cap from the lockshield valve and turn the bolt clockwise with a spanner, as far as you can. Keep track of the number of turns it takes to do this, so you can refasten it to the right balance.
  3. Place your drip tray, tub or bucket under the manual control valve. Brace the valve with one spanner, while using the other to undo the cap nut which connects the valve to the radiator.
  4. Let the water drain, either using multiple tubs or dumping the water into larger bucket. After a few minutes, loosen the bleed valve at the top of the radiator using a bleeding key to increase the flow of water. Don’t forget to close this valve as soon as the flow stops.
  5. Remove the old valve by unscrewing the cap nut which connects it to the water pipe with a spanner. Take the cap nut and olive off as well. This can usually be done by placing the spanner around the pipe, under the olive, and forcing it upwards. If this doesn’t work, you’ll need to saw it off.
  6. If your new valve doesn’t fit with the old radiator connector, you’ll need to remove it. First, loosen it with your spanner, if possible. Then use a hex key to remove it.
  7. Wrap approximately 15cm of PTFE tape around the tail end of the new radiator connector and screw it into the radiator with your spanner. Fit a new nut and olive onto the connector, as well as the pipe. Then wrap some PTFE tape around the top of the pipe where the valve will fit (make sure you clean off any old sealant with steel wool before doing so).
  8. Fit the new radiator valve onto the pipe and screw the cap nut, just using your hands at first. Then screw the cap nut between the valve and radiator connector. Tighten both nuts with your spanner, remembering to support the pipe when you tighten the connector cap nut.
  9. If you’re fitting a TRV, you’ll need to remove the stop cap on the valve and attach the thermostat unit by hand. Turn the thermostat up to a high heat to help refill the radiator.
  10. Reopen the lockshield valve with anticlockwise turns, using as many turns as it took to close it. It’s important to reopen the valve the same amount or you’ll have to rebalance the radiator.
  11. Use the bleed key to let any air out of the radiator, while the system fills back up.

radiator valve replacement

Find out more

For more helpful tips, take a look at our Expert Advice section. Or, pop into your local branch for a chat. We’re always happy to help.

Find out how to remove a radiator completely and 9 ways to keep your home warm this winter. You can browse our full range of radiators, accessories and radiator valves on our product pages.