Replacing a Radiator

You don’t have to drain the entire heating system to replace a radiator, you just turn off the heating and isolate the radiator by closing off the valve at either end. Turn the manual valve clockwise until it wont go any further. Pull off the plastic shield of the lock shield valve at the other end and turn the square shaft clockwise with an adjustable spanner. Count the number of turns so that you can reset the radiator at the same flow rate. If replacing several radiators you will lose corrosion inhibitor from the system so you should drain it down and add some more. Woodford Plumbers can refit radiators.


1). With both valves turned off, use an adjustable spanner to slacken the cap nut holding one of them to the radiator. You may need to hold the valve body with a second spanner or pipe wrench to prevent it turning and buckling the pipe.

2). Place a tray beneath the valve to catch the water as it drains out. Open the bleed valve at the top of the radiator and loosen the cap nut. When the tray is nearly full, retighten the cap nut and empty the tray. Be ready with cloths to mop up any spillages as the water will be filthy. Repeat until all the water has drained out then disconnect the other valve.

3). Lift the radiator and tilt it to drain any remaining water. Stuff tissue into the outlet on the other end to stop it leaking. If the existing brackets don’t suit the new radiator, unscrew them and fit the ones supplied with the new radiator. Check for pipes and cables before drilling new fixing holes. A Woodford Plumber can fit a radiator.

4). Remove the valve connectors from the old radiator, using an adjustable spanner or large allen key. Clean the threads with wire wool and wind PTFE tape around the threads about five times to ensure a good seal. Screw the connectors into the radiator, making sure they are tightened fully. Hang the radiator. Connect the valves and reset them, allowing water to enter the radiator. You will need to open the bleed valve about half a turn so that air can escape, close it when water starts to appear.