Turn off the heating system and let the radiator cool completely
Close the radiator valves
Place towels or a tray under the valves
Loosen the bleed valve to release pressure and drain water
Use two wrenches to disconnect the valve nuts
Remove the radiator from the wall brackets
Lift the radiator away carefully
Check the wall brackets and pipe connections
Install the new radiator onto the brackets
Reconnect the valve nuts tightly
Close the bleed valve
Open the valves slowly
Refill and bleed the radiator to remove air
Check for leaks at all connections
Tighten fittings if needed