Profile: Caltherm Corp. specializes in manufacturing flow control devices. Thermal actuators permit the transforming of heat energy into mechanical energy via the movement of a piston. They are used in a variety of thermostatic applications such as automotive controls, trucks, buses, aerospace, marine, home & commercial heating controls, anti-scald devices, warning systems, compressors and home appliances. Pressure relief valves prevent the possibility of restricted flow & excessive pressures such as during cold weather or a blocked flow passage. These valves allow bypass flow only under conditions of over-pressure, thus preventing the buildup of pressures that could cause damage to a cooler, radiator, hydraulic tubes, hoses and fittings.