1 Remove the old valve

Drain the system and lay cloths under the valve to catch any remaining water. Hold the body of the valve with a wrench and use an adjustable spanner to unscrew the cap nuts that hold the valve to the water pipe and adaptor in the end of the radiator. Lift the valve from the end of the pipe and unscrew the adaptor from the radiator.

2 Preparing the new valve

The threads in the end of the radiator must be clean. Wrap PTFE five times around the threads of the new valve's adaptor then screw it into the end of the radiator by hand. Tighten 1 1/2 turns with a spanner.

3 Fit valve to pipe

Slide the valve cap nut and new olive over the end of the water pipe and fit the valve to the end of the pipe. Align the valve body with the adaptor and tighten the cap nut that holds them together, holding the valve body firmly with a wrench. Next, tighten the cap nut that holds the valve to the pipe. Refill the system and check for leaks, tightening cap nuts as required.