Prestwich Hydroponics® Barbed Anti-Syphon Valve – 6918835667029

An anti-syphon valve is a device used in plumbing and irrigation systems to prevent the backflow of water or other liquids from the system into the main water supply. When a faucet or other water outlet is turned off, a vacuum can form in the pipes, causing water to be siphoned back into the main supply. This can cause contamination of the water supply, leading to health hazards.

An anti-syphon valve works by allowing air to enter the system to break the vacuum and prevent the siphoning effect. It is typically installed in a vertical position, with the valve opening facing upwards. When water flows through the valve, the pressure pushes the valve open, allowing water to flow through. When the water is turned off, the valve closes, and the air is allowed to enter the system, preventing syphoning.

These are available in 13mm (16mm external) and 25mm (32mm external)