Normally Open WRAS Solenoid Valves
£265.00 – £960.00 (excl VAT)
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.
A normally open 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 a water tight housing. When the solenoid is not powered, the core is open in the valve. When energized, a spring puts the valve to its closed 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 1″ do not require any pressure to open them. These are known as zero lift or zero rated valves. Larger valves (above 1″) do require a small amount of pressure in order to operate (0.3bar). This is the differential in pressure between the input side and the output side of the valve. If the pressure is the same on both sides the valve will fail to open/close.