This part is often known by the generic term ballcock although strictly speaking a ballcock is an older form of this valve that is rarely installed anymore.
Roof tank ballcock.
One of the most common toilet repairs is adjusting or replacing the fixture s fill valve.
How to change the ball valve ballcock in your cold water storage tank in the loft.
Make sure the water is turned off by taking off the lid of the cistern or tank and pushing down on the ballcock arm.
They work by rising with the water level in the tank which in turn activates a lever which then shuts the valve.
On a roof tank you should find the tap on the top pipe.
There should be no water gushing out.
Ballcocks also known as float valves are found in water tanks and are used to control the flow of water into the tank.