One-step, mechanical single room controller, bimetal technology, THERMASREG® RTR - B with thermal feedback for monitoring or controlling temperatures in dry rooms, or for activating any kind of heating system, as a room thermostat. For currentless open radiator valves, the cooling output from the changeover contact (normally open contact) must be connected. At breaker contacts, a maximum of 10 valve actuators can be connected and at normally open contacts a maximum of 5 valve actuators.