Understanding the Types of Valves Before Tackling Home Plumbing Repair

You don't need to let that annoying faucet of yours drip another night. Before you can fix this however, you must understand the different valves so you do not make a mistake during home plumbing repair.

There are common types of valves used in home plumbing systems. Keep in mind that water and gas valves are not interchangeable. Use only gas valves for gas.

Gate valve. This valve has tapered a disc or wedge-shaped "gate" that moves across the opening to stop the flow of water and pulls out of the way to let the water flow. When this valve is open, the water can flow straight through with no obstruction or change in direction to impede its full pressure, velocity, and volume. Gate valves are used where a line is either fully open or fully closed most of the time.

Globe valve. This is a compression-type valve with a disc and seat that are set in a partition parallel to the flow of the water. When the valve is open, the water must change direction twice in order to get through, which reduces the pressure, velocity and volume. This is a poor choice of valve for any high-volume water supply line that usually remains fully open. Glove valves are used where a line is opened and closed frequently or where a valve is needed to control the volume and the loss of pressure through the valve will not be problematic.

Angle valve. The mechanism in this valve is very similar to that in a globe valve, but with openings at right angles to each other like an elbow. Because the water only changes direction once instead of twice, an angle valve impedes water flow less than a globe valve. By inserting an angle valve where a pipe turns, you get the benefits of a globe valve without its main drawback, and you eliminate the need for an elbow.

Bleeder valve. Also called a stop and waste or drainable valve, it has a plug on the outlet side that allows water to be drained from the system when the valve has the water shut off. This kind of valve or some other way of draining the system is required by code in cold-weather areas where pipes can freeze in the winter.

Check valve. This automatic valve allows the free flow of water in one direction, but closes if the liquid starts to flow the other way. The primary use of a check valve is on private water supply systems between the well and the pump. It keeps the water in the system from draining back into the well when the pump stops.

Make sure you are familiar and have identified all these valves in your home before taking on a plumbing repair project. It will save you hours of tedious labor if you educate yourself on the valves.