The Viking Model C-1 Thermostatic Release is a rate-of-rise releasing device for use on hydraulic and pneumatic release systems controlling operation of Viking deluge valves on deluge or preaction systems. When subjected to a temperature rise greater than 15° (8.3 °C) per minute, the Model C-1 Thermostatic Release opens to allow pressure in the release system to escape. Video Model C-1 Thermostatic Release - Product Repair Video