radiator balancing

A lockshield valve is the adjustable balancing valve on a radiator, usually on the return side, and it's there to control how much hot water flows through that radiator so the whole house heats more evenly. It's designed to be set with a tool rather than by hand, and typical UK radiator and lockshield valve

Balancing your central heating radiators is a simple but vital job. It just means adjusting the valves on each radiator to make sure hot water from the boiler is shared out evenly across your home. The process involves carefully restricting the water flow to the radiators that get hot first. This encourages more hot water