The antivacuum thermostatic valves series are able to restore the atmospheric pressure inside of a biphasic closed system in an extremely precise and reliable way. At the same time they also act as air vent valve during the heating phase. The key element of the project is a new intelligent actuator system made of a shape memory alloy. According to the temperature it is subjected to, the system is capable of reacting to the heat without any further energy source. Compared to the traditional systems it does not require any electrical power and can be installed in any position and orientation. The techno-polymer body, designed to withstand high temperatures, grants repeatability and reliability in a cost-effective package.