Valves

Many valves are used to control and isolate water supplies and the majority are normally made from brass and that is why plumbers call them brassware. There are valves that have a chrome finish. These types of valves will isolate water supplies so that maintenance and repair work can be carried out on the plumbing without having to drain a whole system. It is good practice to turn valves off and then on again every now and then to keep them in good working order.
Types:
Ball.

This valve contains a ball with a hole drilled through its centre mounted in the supply line. The ball can be turned 90 degrees allowing for the water to flow or not. When the hole through the ball is in line with the pipe work, the valve is open and when the hole is at right angles it is shut. This makes it easy to see whether the valve is open or closed by checking whether the lever or screw head slot is in line with the pipe or across it. A ball valve can be seen on the supply to a washing machine. Always call a professional service like London Worcester Boiler Service.

Gate.
These valves use a wheel on the spindle which pushes a wedge shaped piece in/out to open or close off the supply line and are installed on a low pressure supply. This valve can be used to isolate the supply of cold water to the various cold water taps in the house. If you are replacing a cold tap in the bathroom, for example, this will be the valve that you use to stop the water, assuming the tap is fed by the cold water storage cistern and not from the main. London Worcester Boiler Repair use skilled technicians, familiar with all appliances.

Spindle. 
These type valves all are fitted with a spindle that when turned clockwise, screws down into the valve and pushes a plunger down that will restrict and even stop the water flow, depending on how much you turn. Because the control over the water flow means that this valve is commonly used. These valves also give the best rate of flow due to a light resistance when it is fully open. This valve type is used on taps, radiator valves, lockshield valves, pump valves and gate valves.