A normally closed solenoid valve combines a solenoid (electromagnet core) with a valve body containing one or more entry/exit points. Flow through an orifice is shut off or opened by the movement of the electromagnetic core depending on if the solenoid is energized or de-energized.
The core is in water tight housing. When the solenoid is powered, the core directly opens the valve. When de-energized, a spring returns the valve to its original position. The force needed to open the valve is proportional to the valve size and water pressure.
Depending on the size of the valve, will depend on what pressure is required to open or close it. Valves between 1/2″ and 2″ do not require any pressure to open them, these are known as zero lift or zero rated valves.
Ideal for applications where there is an intermittent requirement to open and close the valve to allow water to flow is needed. This could be in respect of a process that needs water on demand such as a vending machine or when water is not required if nobody is present, such as in an office WC area.
The Water Regulations Advisory Scheme (WRAS) is a conformance mark that demonstrates that an item complies with high standards set out by water regulations official proclamation in 1999 in the United Kingdom. It is enforced in the UK by the water supply companies. WRAS covers all plumbing systems, water fittings, and equipment supplied, or to be supplied, with water from the public water supply. It is not illegal to install a product such as water fittings in the UK without the WRAS mark but it may have to have compliance in other ways.
Commonly called 2/2 (2 way/2 position) valves, the normally closed solenoid valve has 1 inlet and 1 outlet that allows installation into a pipe and will shut off the fluid within it.