GRENTON thermoelectric actuator is a dedicated actuator for use with zone valves or with thermostatic valves in manifolds for floor heating. The actuator is made in the NZ (NC) version, it is to allow the flow of liquid in the heating system that a nominal voltage supply is required. The First Open function allows the heating system to function by opening the actuator during the start-up / installation phase without the need to supply the device with rated voltage. Thermoelectric actuator in NZ (Normally Closed) configuration. The actuator opens when it is supplied with 230V. Allows precise control of room temperature by controlling the supply of hot water to the radiator. Visible element indicating opening or closing. In the closed state it does not consume power. "FIRST OPEN" function - for easy installation of the actuator. Easy to install vertically or top-down.