Check valves prevent reverse flow of fluids and gases within a pipeline system. They are designed to allow fluid to flow one way through the pipeline. Due to the simple design, check valves generally operate without automation or human interaction and instead rely on the flow velocity of the fluid to open and close. You can learn more in our complete check valves guide.

How do they work?

Check valves are flow sensitive and rely on the line fluid to open and close. The internal disc allows flow to pass forward, which opens the valve. The disc begins closing the valve as forward flow decreases or is reversed, depends on the design. Construction is normally simple with only a few components such as the body, seat, disc and cover.

Check Valve types

There are several types of check valves for just about any application. Some of the more popular types include:

● Ball

● Dual plate

● Double door

● Spring assisted inline

● Nozzle

● Piston or lift

● swing checks

As with other types of valves, speciality check valves can be found for special applications.

Check valves are found in just about any type of facility from industrial plants and homes.

How much do check valves cost?

Depending on the size of the system and how much it costs, most homeowners pay between $135 and $1,000. The device costs between $35 and $600, while labor costs between $100 and $400. You can expect to pay between $70 and $250 for a back water or check valve.

What is a check valve used for?

The main purpose of a check valve is to prevent backflow in the system. Figure 1 shows an example of a check valve. A check valve relies on a pressure differential to work. They require a higher pressure on the input side of the valve than the output side to open the valve.

How often should a check valve be replaced?

While typical component lifespans are application specific, manufacturers suggest metal and plastic check valves should be replace every 5-7 years whereas check valves manufactured from rubber may remain fully serviceable for up to 35-50 years.

Do I need a check valve?

Do I need a check valve? A check valve is a valve that is used to prevent backflow in a piping system. ... Even if a pump does have a built-in check valve, we recommend that a check valve be installed in the discharge line within 25 feet of the pump and below the draw down level of the water supply.