{"product_id":"mcdonnell-miller-114642-fs4-3ds-1-stainless-steel-flow-switch","title":"McDonnell \u0026 Miller 114642 FS4-3DS 1\" Stainless Steel Flow Switch","description":"\u003cp\u003eProtect your hydronic equipment from damage caused by low-flow conditions with the \u003cstrong\u003eMcDonnell \u0026amp; Miller 114642\u003c\/strong\u003e, model \u003cstrong\u003eFS4-3DS\u003c\/strong\u003e. This precision-engineered flow switch is designed to monitor liquid flow in HVAC and industrial systems, triggering an automatic response if flow rates drop below the required safety threshold to prevent potential overheating or pump cavitation.\u003c\/p\u003e\u003cp\u003eThe unit utilizes a sensitive paddle mechanism that extends into the piping, detecting movement and actuating its internal dual SPDT switches. This dual-switch configuration provides enhanced versatility, allowing for simultaneous control of secondary equipment or alarm signaling, while the stainless steel construction ensures long-term resistance to corrosion and fluid impurities.\u003c\/p\u003e\u003ch4\u003eKey System Performance Baselines:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable Construction:\u003c\/strong\u003e High-grade stainless steel body built for demanding fluid applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eControl Versatility:\u003c\/strong\u003e Equipped with two SPDT (Single Pole Double Throw) switches for multi-circuit logic.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReliable Sensing:\u003c\/strong\u003e Designed for precise flow detection in 1-inch piping systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSystem Safety:\u003c\/strong\u003e Prevents equipment failure by ensuring constant circulation in HVAC loops.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e⚠️ \u003cstrong\u003eApplication Profile:\u003c\/strong\u003e Ideal for use in commercial boilers, industrial chillers, water treatment systems, and liquid transfer lines where real-time flow monitoring and secondary shut-off or alarm activation are required for safe operation.\u003c\/p\u003e","brand":"McDonnell \u0026 Miller","offers":[{"title":"Default Title","offer_id":43123966541918,"sku":"114642","price":738.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0663\/7151\/8558\/files\/114642_image_9649cfb8-125d-490d-9d84-d1c7a0181c74.png?v=1786027260","url":"https:\/\/nationalboilersupply.com\/products\/mcdonnell-miller-114642-fs4-3ds-1-stainless-steel-flow-switch","provider":"National Boiler Supply","version":"1.0","type":"link"}