Siemens 242-00210 ZONE VALVE, 2-WAY, 1/2", 1.0 CV, NPT W/ 24V 2-POSITION SR ACTUATOR FAILS NCSiemens 242 00210 Zone valve, 2 way, 1 2", 1. 0 Cv, NPT w 24V 2 position SR actuator fails NCZone valve and actuator assembly. 2 way valve body; NPT connection; Line size 0. 50 inch; Flow rate 1. 0 Cv; SFA11U 2 position, spring return actuator; 24 Vac; normally closed. Zone valve and actuator assembly. 2 way valve body; NPT connection; Line size 0. 50 inch; Flow rate 1. 0 Cv; SFA71U 2 position, spring return actuator; 24 Vac; normally closed.