A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. Small valves may be so compact as to be barely noticeable, particularly when they are integrated into the bodies of existing taps (faucets).
Similarly, you may ask, why do you need a double check valve?
Double check valves protect the water supply from the risk of backflow and back siphonage in domestic homes and commercial buildings, ultimately preventing potential contaminants getting into other parts of the system, especially drinking water.
Also Know, how do you use a double check valve? The double check valve only allows water to flow through in one direction, therefore, preventing backflow of potential contaminants. To install, simply push the valve fully on to the pipe. Should the need arise to demount the connection push the collet towards the body of the fitting and pull the pipe to release.
Regarding this, what is the difference between a double check valve and a backflow preventer?
The main thing to take away from this is that both backflow prevention device types perform the same function when they are operating properly, but only the RPZ is designed to protect the public water supply by disposing of any backwards-flowing water if any of the check valves or the relief valve fails.
Does a double check valve reduced flow?
Double check valves allow water to flow only in one direction, therefore preventing the reverse flow of water and any harmful chemicals reaching the home. It is comparable to the design of the human heart valve; it allows the flow of water through one way and closes if pressure comes back through.
19 Related Question Answers Found
What is the difference between a single check valve and a double check valve?
the difference between double check valve and single check valve. A double check valve is merely two single check valves in close series. A single check valve stops backflow, but miniscule amounts of “contaminated” water will have passed back along the pipe before it closes.
Why do I need a check valve?
Check valves are designed to permit water to flow in one direction and are a requirement on all submersible pump installations. Their job is to prevent water in the column above the pump and in the pressure tank from draining back into the well when the pump shuts off.
When should I use a check valve?
Stop-check valves can be used for many applications. They’re designed to start, stop, and regulate the flow of materials, and they help to prevent backflow. If pressure in the system is too low, these valves will automatically close to prevent reverse flow. As a result, damage usually caused by backflow is prevented.
How does a double check backflow preventer work?
Double Check Valve Assembly – DC The two check valves (1st & 2nd Check) will have similar spring loadings. The check valves in a DC will open when something downstream of the DC in the piping system opens a water-using fixture, and as the water begins to flow to that fixture, the pressure drops.
Can a double check valve be installed vertically?
There are backflow preventers that can be installed horizontally, vertically (up or down) and other orientations that can make an installation easier. The key point to realize however is that they can only be installed in the orientation that the approval agency has determined they will work in.
Where should you use a check valve?
Check valves are used in many different applications. For example they are often placed on the outlet side of a pump, to protect the pump from backflow. Centrifugal pumps, the most common type of water pumps, are not self-priming, and therefore check valves are essential for keeping water in the pipes.
Do I need a non return valve on mixer tap?
If your tap is not dual-flow, then you would need non-return check valves on both the hot and cold feed pipes to stop the water mixing (it might be that the cold pressure sometimes falls, drawing hot water into the cold pipe via the leaky tap).
Do non return valves restrict flow?
Non-return valves (check valves) are mechanical valves that permit gases or liquids to flow in only one direction, preventing flow from reversing down the line. They are classified as one-way directional valves. Fluid flow in the desired direction opens the valve, while backflow forces the check valve to close.
Can I use a check valve instead of a backflow preventer?
A backflow preventer protects your potable water. A check valve controls flow but it is not absolute. A check valve is not an appropriate substitute for a backflow preventer.
Does a backflow preventer reduced pressure?
The reduced pressure is guaranteed by a differential pressure relief valve, which automatically relieves excess pressure in the chamber by discharging to a drain. It is theoretically possible that, when both valves are faulty, backflow could occur, should the reverse flow rate exceed the capacity of the relief valve.
What are the different types of backflow preventers?
6 Types of Backflow Preventer Explained Atmospheric Vacuum Breaker. This is an elbow-shaped device bent at a 90 degree angle. Chemigation Valve. This type of valve is used on agricultural areas. Hydrostatic Loop. When pipes are arranged into a vertical form it is referred to as a hydrostatic loop. Double Check Valve. Reduced Pressure Zone Device. Air Gap.
What are double check valves used for?
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination.
Do I have a backflow preventer?
The key to preventing backflow is to have a properly installed, maintained, and inspected backflow prevention device as part of your culinary water system. The answer is: you need backflow prevention if you have a culinary water connection that may be used to supply a sprinkler system.
How much does a backflow valve cost?
Backflow parts cost between $35 and $900. Labor costs between $35 and $250. Backwater valve installation, a different process, costs between $125 and $250 to install on a new system. These valves cost around $500 to $1,000 to retrofit onto an existing system.
What is the difference between a backflow preventer and a vacuum breaker?
A hose connection vacuum breaker should be installed on each faucet or hose bibb that is connected to the potable water supply to prevent backflow into the water supply. An HVB prevents backflow to the water supply by venting water to the atmosphere (onto the ground) when backflow conditions exist.
What are four types of approved backflow prevention devices?
Types Of Backflow Preventers Overview Of Four Common Backflow Preventers Pressure Vacuum Breaker. Pressure Vacuum Breaker Assemblies: Double Check Valves. Double Check Valve Assemblies: Reduced Pressure Zone Assembly. Reduced Pressure Zone Assemblies: Atmospheric Vacuum Breaker (Anti-Siphon)
How does a check valve work?
Simply put, a check valve allows flow in one direction and automatically prevents back flow (reverse flow) when fluid in the line reverses direction. They are one of the few self-automated valves that do not require assistance to open and close.
What is a tap with double check valve?
A device must be installed in the pipework to prevent water being drawn back into the household water supply should a negative water pressure be created. The usual device fitted is a double check-valve which basically incorporates two spring loaded non-return valves.
What is the difference between a check valve and a non return valve?
A non-return valve allows the flow of fluid in only one direction. A check valve also allows flow in one direction and automatically prevents backflow when fluid in the line reverses direction. Typically the check valves are designed for a specific cracking pressure.