In general, radiators feature a pair of valves on the pipes which enable hot water to enter them.
The main radiator valve, often referred to as a control valve, is used to switch the radiator on and off for typical everyday use. This valve can also adjust the amount of water entering the radiator to alter temperature.
The other valve is the lockshield valve, which is an integral tool in balancing out each radiator within a heating system.
For more information, consult our Radiator Valve Guide.