1/2" Part 1 High Pressure Brass Ball ValveModel: R306206.
Suitable for high pressure incoming water mains the Part 1 ball valve is ideal in cold water storage tanks. Designed with interchangeable parts to make replacement easy.
 
Part 2 ball valves are intended for mains-fed cold water storage cisterns and feed and expansion cisterns, and are by far the preferred choice over Part 1 ball valves. This is because Part 2 ball valves offer a much greater air gap between the water exit point on the valve and the water level in the cistern if it reaches “critical level”, i.e. the same level as the pipe centre line. Part 2 ball valves also have a specifically designed mechanism for adjusting the water level in the cistern, whereas the only way to do so on a Part 1 ball valve is to bend the float arm.
Current water regulations no longer permit the use of a Part 1 ball valve on a cold water storage cistern. While a faulty Part 1 ball valve on a pre-existing installation can be repaired, it should ideally be replaced with a Part 2 ball valve – especially if the old valve has a rigid tube which dips down into the water in the cistern. These ‘silencer’ tubes are prohibited by water byelaws.