Siemens 242-00231 ZONE VALVE, 3-WAY, 1/2", 2.5 CV, NPT W/ 24V 2-POSITION SR ACTUATOR, FAILS AB-BSiemens 242 00231 Zone valve, 3 way, 1 2", 2. 5 Cv, NPT w 24V 2 position SR actuator, fails AB BZone valve and actuator assembly. 3 way valve body; NPT connection; Line size 0. 50 inch; Flow rate 2. 5 Cv; SFA11U 2 position, spring return actuator; 24 Vac; fails AB B. Zone valve and actuator assembly. 3 way valve body; NPT connection; Line size 0. 50 inch; Flow rate 2. 5 Cv; SFA71U 2 position, spring return actuator; 24 Vac; fails AB A closed.