Lockshield valves are used in plumbing systems to open and close water supply to radiators, effectively turning them on or off. The valves are usually located in the piping next to the radiator, and can be identified by the presence of an Allen key bolt. You might want to open lockshield radiator valves to switch on the radiators in your office as winter or a period of cool weather approaches. Allow about a minute for each valve.

Locate the valve near the skirting boards where the piping enters the radiator.

Insert a #6 Allen key into the bolt in the valve. Alternatively, rotate the screw cap clockwise.

Turn the bolt clockwise a few times to open the valve. Water will begin entering the radiator.

Close the valve by turning the Allen key counterclockwise until tight.