STC45

Electrothermal actuator for zone valves and terminal units, connectable to Siemens VGZ 2-way, XGZ 3-way and XGZ+TXZ 3-way 4-port valves. It consists of an expanding thermostatic element (PTC) which, upon receiving the 24 Vac command, causes a piston to extend and push down the valve stem, overcoming the return spring of the valve body. The actuator is made with double thermal insulation, a plastic cover, and a manual control knob for operation without power.
The STC45 product comes standard with an auxiliary microswitch whose function is typically to stop the circuit pump when the valve is closed.