A proportional thermoelectric actuator which, when used together with the TA-Modulator, TBV-CM, provides superbly accurate modulating control and a high enclosure class. Used together with thermostatic radiator valves it provides a more accurate room temperature control than On/Off control. A long life is ensured by the unique design. The position indicator is visible from all sides which allows easy maintenance procedures. A high adjusting force further enhances reliability.