There are many different valves available to aid in the control of plumbing and heating systems. The list below includes some of the most common valves used in plumbing systems and describes when and why they are used.
Ball Valves are the most common valve used in plumbing and heating systems. A ball valve is opened by turning a handle that is attached to a ball inside the valve. The ball has a hole or port in the middle of it that allows water to flow through when it is in line. When the valve is closed, the hole turns perpendicular to the ends of the valve and flow is stopped. The term full port refers to the fact that the hole in the ball is the same size as the pipeline and does not restrict flow.
Boiler drains are horizontal faucets that have male or female threads that are angled perpendicular to the bottom of the valve. They are called boiler drains because they were designed to drain water from a boiler to remove sediment. Boiler drains may also be used for a laundry tub to hookup to a washing machine.
Check valves ensure that water is only able to flow through in one direction and not back in the other direction. They are often used in plumbing and heating systems. These valves come in spring loaded and swing varieties.
Frost free sillcocks are used to prevent frozen pipes in a residential plumbing application. They accomplish this by keeping the valve inside the house and away from the cold. Frost free sillcocks are most commonly used for garden hoses.
Gas ball valves are used in residential applications to aid in the control of natural gas and liquid propane. They feature a ball and handle that will allow the gas line to be turned off.
Gate valves open by lifting a rectangular wedge out of the water line. Gate valves are often used for regulating the flow of water. However, some of these valves are designed to either be fully opened or closed.
Sillcocks are faucets that are designed to be installed horizontally on the outside wall. These are commonly used for connecting to a hose in residential applications.