This Apollo Valve 13202 series steam relief valve is a safety valve for protecting small to medium lowpressure steam heating boilers. It has a cast bronze body, a 5 pounds per square inch (psi) relief pressure, a 1 male National Pipe Thread (NPT) inlet connection and 1 female NPT outlet, and a PTFE (polytetrafluoroethylene) seat. The valves body and nozzle are bronze and the spring is steel for resistance to corrosion. The flat seat is a PTFEfaced disc for positive seal, resistance to moisture and high temperatures, and positive drainage of condensate from the seat area. The valve can be used in operating temperatures up to 250 degrees F. This relief valve is American Society of Mechanical Engineers (ASME) safety rated for Section IV heating boilers and is suitable for lowpressure steam heating and supply boilers.Relief valves remove excess pressure or vacuum from a system. The valve openings allow fluids or gases to escape to decrease pressure, and then close once the valve reaches the reseating pressure limit. They also relieve excess vacuum by opening to release a gas into the system and then closing after it reaches its lowpressure limit. Some relief valves have an adjustment mechanism to set the pressure where the valve opens, making it suitable for various applications. Relief valves are rated according to the volume of liquid or gas that can flow through them and the material that the valve is constructed from must be suitable for the fluid or gas, which may be corrosive or at an extreme temperature, in which it operates. Relief valves are used in a variety of applications, such as air compressors, petrochemical and chemical manufacturing, natural gas processing, and power generation.Apollo Valves manufactures ball, mixing, and relief valves, actuators, water gauges, marine fittings, heating and plumbing products, and backflow prevention. The company, founded in 1928 and headquartered in Matthews, NC, meets international standard International Organization for Standardization (ISO)/IEC standard 17025:2005.