FAQ: What does a flow check valve do?

Flow check valves are controls that prevent hot or chilled water from circulating in the heating or cooling system at certain times. We offer flow check valves (or boiler check valves) that provide positive shutoff when the circulator is not running, preventing the flow of water to radiation units.

How does a flow check valve work?

A check valve is a device that only allows the flow of fluids in one direction. … They require a higher pressure on the input side of the valve than the output side to open the valve. When the pressure is higher on the outlet side (or the input side pressure is not high enough), the valve will close.

What is the difference between a check valve and a backflow preventer?

Check valves are used in a wide variety of equipment, cars, planes, pneumatic and fluid systems, while backflow preventers are typically used in plumbing systems for structures. A check valve has a variety of roles but is mostly used to regulate and control the flow of fluids, especially into pumps.

What is the main purpose of a check valve?

Check valves are one-way or nonreturn valves that open with fluid movement and pressure, and close to prevent backflow of the pressure to upstream equipment such as pumps and compressors. In fact, check valves allow the fluid to flow in only one direction.

Does a check valve restrict water flow?

Check valves are designed to prevent water flowing in one direction while moving somewhat freely in the other direction. … The guts of a swing check valve. This one’s corroded “axle” (often made from brass) allows the gate to fall into the water stream, preventing it from checking or reducing flow.

Does a check valve reduce water pressure?

No. A check valve prevents backflow. A pressure reducing valve can regulate water pressure. A PRV can be either a fixed outlet pressure or a dial up type can be adjusted to suit application.

Does a check valve go before or after a pump?

The most common installation is at the pump. A check valve may be installed on the suction side of the pump to maintain the pump’s prime in the event of a pump shutdown. A check valve will be used commonly on the discharge of the pump to prevent backflow from the downstream system, when the pump shuts off.

Where should a check valve be installed?

Check Valve Installation and Piping Design Guidelines Webinar

Is a check valve the same as a back flow valve?

Backflow occurs when pressure changes in pipes cause the flow of liquids, gas, or semisolids to reverse in the wrong direction. Check valves are designed to ensure substances in a pipe only flow one way, automatically closing to prevent unwanted backflow if the direction is reversed.

When would you use a swing check valve?

Swing check valves function well with a variety of media, including liquids and gases. Some frequent use cases for swing check valves include firefighting equipment, flood prevention in sewage systems, and toilet flush mechanisms.

Is a check valve necessary?

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.

Do I need a check valve and a foot valve?

We recommend using only one check valve or foot valve in a pump system. A foot valve should be at the inlet to the suction line of turbine, centrifugal, and jet pumps. … If an additional check valve is required, it should be placed after the pressure tank to allow the pump and discharge pipe to remain pressurized.

What is the importance of check valves in hydraulic system?

Check valves are the simplest form of hydraulic devices in that they permit free oil flow in one direction and block oil flow in the opposite direction. Check valves may also be used as a directional or pressure control in a hydraulic system.

Can a check valve get clogged?

A preventer can provide years of service without any problem, but if either of the two check valves inside the device becomes clogged with debris or a mineral buildup, it spits water into an open-ended vertical pipe.

Do you need a check valve on water line?

Check valves used on well water system piping are used to hold pressure in the system when the pump stops. Check valves on well piping also prevent backspin of the well pump, water hammer and upthrust inside the pump.

How do I know if my valves are failing?

For example, failing check valves will start to vibrate and even lose some internal parts when problems begin to arise. Other symptoms of check valve failure include reverse flow and excessive component wear and damage. Check valves will also emit noises as they start to break down.

Will a check valve prevent siphoning?

Check valves allow one directional water flow and are used to prevent back siphoning. They are commonly used on return pump outputs to prevent water overflowing the sump in the event of a power outage, pump failure or maintenance.

How long do check valves last?

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.

What is check valve obstruction?

The check valve mechanism of airway obstruction is a condition usually associated with the aspiration of an exogenous foreign body [3]. However, in this case, the cause of the tension pneumothorax was considered to be the check valve formation by a blood clot mixed with numerous fungal hyphae in the carina.

How far should check valve be from sump pump?

Best height ( unless owner’s manual states otherwise) is two to three feet off of the top of the sump pit. This way your sump pump motor doesn’t have to work as hard as when your check valve is in lower position.

How much pressure does it take to open a check valve?

The minimum upstream pressure required to operate the valve is called the cracking pressure, generally between 1 and 5 psi. Check valves are designed specifically with this number in mind. The degree of opening on a check valve is determined by the flow rate.

Does a water heater need a check valve?

Check valves are important in a water heater because they prevent flooding or overflowing. They also stop the water from constantly flowing backwards, even when the heater is off. This prevents eroding of the pipes and saves power.

How much does it cost to install a check valve?

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.

Do toilets have check valves?

Since toilet water lines do not contain drinking water they do not need the extra protection a backflow preventer offers – all you need is a check valve in most cases but some areas require a sewer backflow preventer if it is near the plumbing impacting the water supply.

Do you need a check valve on a shower?

Plumbing Code Requirements

Plumbing codes require that hand-held showers be provided with backflow protection. Backflow protection can be an air gap, two independent check valves, or a vacuum breaker. … If a second check valve is required, a handshower hose that contains a check valve should be used.

Do I really need a backflow preventer?

Understand that it is always recommended to install a backflow preventer in any situation where incoming water and waste water have a chance of being cross-connected. This serves to protect you and your home, keeping your drinking, bathing, and cleaning water safe.

Which is better swing check valve or spring check valve?

A spring loaded check valve will help minimize effects of water hammer, while a swing check valve can exacerbate the issue. Any water hammering effects present in a piping system can potentially be amplified by a swing check valve.

Will a check valve work horizontally?

Check valve can be installed in horizontal or vertical piping runs, with the flow running upward. Mounting for vertical installations is critical.

What is the difference between wafer check valve and swing check valve?

Wafer check valves get their name from their wafer thin design. These valves are sleek and made to fit in tight spaces between two flanges. … Swing check valves, as the name implies, also uses a swinging disc to allow or block flow. The difference between the two is in the body design.

Why do I need a check valve on a sump pump?

Sump pump check valves are an important part of any sump pump system. Installed in the discharge pipe leaving your sump pump, the sump check valve prevents your pump from having to re-pump water it has already discharged.

Should I have a check valve on my sump pump?

If you do not have a Check Valve installed, it will cause your system to work much harder and more often to pump out the same amount. Installing one of these valves will drastically reduce the stress that is put on your pump and save energy by limiting the amount that the pump needs to run.

Should a bilge pump have a check valve?

Parts Needed. And no, you should not use a check valve in the bilge pump line to prevent the back flow of water. The use of a check valve is not recommended due to the potential for sticking and causing the pumping system to fail. … Therefore, it’s a good idea to remove as much of that water as possible.

Do I need a check valve on my shallow well pump?

Do I need to use a check valve or foot valve with this pump? Yes. The check valve should be installed in the suction side piping as close to the source of water as possible.

Where do you put a check valve on a irrigation pump?

Sprinkler Pump Loses Prime Check Valve Replacement – YouTube

Do I need a foot valve on a shallow well?

Foot valves are used in shallow well jet pump and deep well jet pump installations. The foot valve is required to be installed at the bottom of the well suction line piping. … If you notice that a shallow well no longer has any water, one of the first things to check would be if the foot valve needs to be replaced.

How do I know if my hydraulic valve is bad?

3 Signs Of Pressure Relief Valve Failure

  1. System Cannot Reach Pressure. If your system isn’t reaching pressure, this could be a sign of pressure relief valve failure. …
  2. System is Over Maximum Pressure. …
  3. Pressure Relief Valve is Leaking or Has No Pressure.

Why do check valves chatter?

Chattering occurs when the valve is oversized for the application and is one of the most common causes of check valve failure. … By knowing the temperature, pressure, media, flow rate, and viscosity we can help to determine the flow characteristics of the valve when in service.

What is the most common application of a check valve in a hydraulic system?

What is the most common application of a check valve in a hydraulic system? Allowing free flow of fluid through a line in one direction, while preventing reverse flow in that line. A three-way directional control valve has 3 ports. Describe what each port is connected to in the system.

How do I know if my check valve is working?


How do you unclog a check valve?

Step 1: Use the two wrenches and carefully unscrew the check valve, being careful not to lose the spring and ball valve on the inside. Step 2: Rinse or wipe in order to clear any debris from the inside of the check valve. Pay particular attention to the ball or where the ball has contact inside the check valve.

Can a check valve be repaired?

1 Inch Spring Check Valve Repair – YouTube

Why do valves fail?

A: Failures in valves can be caused by many factors. Some of the more prominent causes include: Wear of the elastomers and/or seat seals over time. Temperatures or pressures outside the designed operating parameters, especially unexpected pressure spikes in the pipeline.