Guide to replace a damaged radiator step by step

How to replace a damaged radiator valve

Radiator valves are used to control and isolate the water flow within a radiator. If you’re experiencing difficulties getting one radiator to heat up fully this could be due to a faulty radiator valve.

To replace your radiator valve without needing the help of a heating engineer, follow these eight steps.


What do I need to repair a damaged radiator valve?


  • A spanner
  • PTFE tape (also called plumber's tape, this is typically used to seal pipe threads)
  • A wrench
  • A hose
  • A jubilee clip (a circular metal band or strip designed to hold a hose onto a circular pipe)
  • Wire wool
  • A new valve
  • A dry cloth


1. Drain the system


Before you start any work on your central heating system you’ll first need to drain it.

If you have a combi boiler you can do this yourself following the steps below, however if you have a conventional cylinder tank system you’ll need to contact your local heating engineer for assistance.


  • Usually found at the lowest point in the pipework, connect the hose to the drain cock and secure with the jubilee clip.
  • Run the hose outside and open the drain cock.
  • Wait until all the water has left the system before moving on to the next step.


2.  Remove the old valve 


  • Place the dry cloth under the valves in order to catch any water left in the system.
  • While holding the body of the valve with a wrench, use an adjustable spanner to unscrew the cap-nuts and remove the valve from the end of the pipe.
  • Use the wire wool to clean the area directly surrounding the valve.


3. Remove the old adaptor


  • To remove the old adaptor, simply unscrew it using an adjustable spanner. Depending on the type of adaptor you have you may find it easier to use a hexagonal radiator spanner.
  • Use the wire wool to clean the area directly surrounding the adaptor.


4. Fit the new adaptor


  • Start by winding the PTFE tape around the threads 4-5 times.
  • Attach the new adaptor to the end of the radiator and tighten with a spanner.


5. Fit the new valve


  • Slide the valve cap-nut and sealing components over the end of the pipe and attach the new valve. Be careful not to tighten the cap-nut too early.
  • Use the wrench to align the valve with the adaptor, and then tighten the cap-nut that holds them together.
  • Make sure you also tighten the cap-nut that holds the valve to the water pipe.


6. Refill the system


  • Locate the filling loop, usually found underneath your boiler.
  • Turn the valve and increase it until the pressure gauge reaches 1.5.


7. Bleed the radiators


Releasing trapped air thus allowing hot water to circulate easily, bleeding your radiators is a straightforward process.


8. Refill the system again


Once you’ve removed trapped air from the radiators, go back to the filling loop valve and turn it again, until the pressure gauge returns to 1.5.

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