The RTS Series complies with the requirements of NFPA 13 and 72 for a room temperature switch to operate at 40°F to protect a dry pipe valve from freezing. The RTS can also be used for other temperature detection applications. The normally open detector, RTS-O, will close the contact when the temperature drops below 40°F (4,5°C). The normally closed detector, RTS-C, will open the contact when the temperature drops below 40°F (4,5°C). The detector will automatically reset to the normal state when the temperature rises above 40°F (4,5°C). The RTS Series Room Temperature Sensors are precision engineered, designed and manufactured for commercial or residential use.