Siemens 656-0010 ASSEMBLY, 1/2", 3-WAY WATER MIXING (2.5CV) OR AIR STATION PILOT VALVE (3-8PSI)Siemens 656 0010 Assembly, 1 2", 3 Way water mixing (2. 5Cv) or Air Station Pilot Valve (3 8psi) This is a 656 Series Valve Assembly with a 1 2" Line Size, with 3 Way Pilot Valve Action and Flow rate of 2. 5 Cv. This item can also serve as air station equipment which rapidly responds to large volume demands and supply pressure variations. This pneumatic pilot valve is used in two pressure systems for either day night or heat cool applications. This