MVR actuators are designed for mounting on manifolds for floor, ceiling and wall radiant panels on heating or air conditioning plants. MVR actuators are of electro-thermal type and are controlled by an on-off signal or, 24 Vac models only, also by pulse width modulation. Actuators are powered by the control signal; this causes the heating of a thermostatic element. Consequently a small piston comes out and, opposing to return spring, lowers the valve stem. MVR...M models are equipped with an auxiliary microswitch. The microswitch has the contact closed when the actuator isunpowered.