{"product_id":"siemens-building-technology-257-02031-control-valve-assembly","title":"Siemens Building Technology 257-02031 Control Valve Assembly","description":"\u003cp\u003eFor veteran mechanical contractors managing commercial hydronic systems, the \u003cstrong\u003eSiemens 257-02031\u003c\/strong\u003e provides a reliable, field-proven solution for precise fluid regulation. As a core component of the \u003cstrong\u003ePowermite 599 MT Series\u003c\/strong\u003e, this \u003cstrong\u003e2-way normally open pneumatic control valve\u003c\/strong\u003e is engineered for terminal units, hydronic heating coils, and chilled water applications. The assembly integrates a high-performance \u003cstrong\u003e1\/2\" brass globe valve\u003c\/strong\u003e with a 2-inch pneumatic actuator, calibrated for a 3–8 PSI spring range to ensure seamless integration with existing building automation systems (BAS).\u003c\/p\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eSiemens 257-02031\u003c\/strong\u003e features a \u003cstrong\u003e0.4 Cv\u003c\/strong\u003e flow coefficient with a modified equal percentage characteristic, allowing for superior modulating control and improved system balance under varying load conditions. Designed for tight spaces, the 1\/2\" NPT internal thread by union male external thread configuration simplifies installation and serviceability. With an ANSI Class 250 rating and a forged brass body, this \u003cstrong\u003eHVAC modulating valve\u003c\/strong\u003e maintains its structural integrity at temperatures ranging from 35°F to 250°F, providing the durability required for high-cycle industrial environments.\u003c\/p\u003e\n\n\u003cstrong\u003eKey Benefits for Technicians:\u003c\/strong\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrecision Modulation:\u003c\/strong\u003e The 0.4 Cv \u003cstrong\u003eequal percentage flow characteristic\u003c\/strong\u003e ensures accurate temperature control in terminal units.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRugged Construction:\u003c\/strong\u003e Built with a forged brass body and brass trim to resist corrosion and handle \u003cstrong\u003eANSI Class 250\u003c\/strong\u003e pressure requirements.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaintenance Optimized:\u003c\/strong\u003e The union male connection allows for rapid removal and replacement without cutting into the piping header.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePneumatic Reliability:\u003c\/strong\u003e Features a 2-inch \u003cstrong\u003eSiemens pneumatic actuator\u003c\/strong\u003e designed for consistent response in air-driven control loops.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cstrong\u003eCommon Questions:\u003c\/strong\u003e\n\u003cp\u003e\u003cstrong\u003eIs the 257-02031 compatible with 2-pipe systems?\u003c\/strong\u003e\u003cbr\u003e\nYes, this normally open 2-way valve is ideal for 2-pipe heating or cooling configurations where the valve must fail-safe to the open position upon loss of control signal.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat media can this Siemens valve handle?\u003c\/strong\u003e\u003cbr\u003e\nThis valve is designed for use with water or water-glycol solutions containing up to 50% antifreeze, making it suitable for both chilled water and low-pressure steam applications.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCan I replace just the actuator on this assembly?\u003c\/strong\u003e\u003cbr\u003e\nThe assembly utilizes the standard \u003cstrong\u003e599-01088\u003c\/strong\u003e pneumatic actuator, which can be serviced or replaced independently of the valve body if the mechanical trim remains intact.\u003c\/p\u003e\n\n\u003cp\u003eDisclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.\u003c\/p\u003e","brand":"Siemens Building Technology","offers":[{"title":"Default Title","offer_id":43682884714674,"sku":"257-02031","price":144.68,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1838\/2375\/files\/Pic_5dd6d402-40d4-4b2e-af95-b9515fb07195.png?v=1775705564","url":"https:\/\/www.gsistore.com\/products\/siemens-building-technology-257-02031-control-valve-assembly","provider":"GSIstore","version":"1.0","type":"link"}