{"product_id":"mcdonnell-miller-114639-fs4-3rp-t-1-flow-switch-with-test-button","title":"McDonnell \u0026 Miller 114639 FS4-3RP-T 1\" Flow Switch with Test Button","description":"\u003cp\u003eMaintain precise liquid flow monitoring in your HVAC and process systems with the \u003cstrong\u003eMcDonnell \u0026amp; Miller 114639\u003c\/strong\u003e flow switch. This model \u003cstrong\u003eFS4-3RP-T\u003c\/strong\u003e is specifically engineered to detect the presence or absence of flow in pipelines, providing critical interlocking control to protect equipment from dry-firing or flow-related damage.\u003c\/p\u003e\u003cp\u003eThe unit utilizes a precision-engineered paddle mechanism that responds to fluid movement within the pipe. When flow reaches the calibrated velocity, the paddle shifts, actuating a snap-acting switch to signal the control circuit. The integrated test button allows technicians to simulate flow conditions instantly, ensuring the system remains operational without requiring actual pipe-line manipulation.\u003c\/p\u003e\u003ch4\u003eKey System Performance Baselines:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnhanced Safety:\u003c\/strong\u003e Built-in test button functionality for rapid on-site diagnostics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReliable Switching:\u003c\/strong\u003e Precision snap-action design for consistent electrical contact.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRugged Construction:\u003c\/strong\u003e Built to withstand the demands of industrial hydronic loops.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e⚠️ \u003cstrong\u003eApplication Profile:\u003c\/strong\u003e Ideal for monitoring flow in chilled water systems, hot water heating boilers, booster pumps, and liquid transfer lines where system protection and flow verification are mandatory requirements.\u003c\/p\u003e","brand":"McDonnell \u0026 Miller","offers":[{"title":"Default Title","offer_id":43123964903518,"sku":"114639","price":285.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0663\/7151\/8558\/files\/114639_image_c44bf373-fd04-4588-9889-d28403a757e7.png?v=1786027202","url":"https:\/\/nationalboilersupply.com\/products\/mcdonnell-miller-114639-fs4-3rp-t-1-flow-switch-with-test-button","provider":"National Boiler Supply","version":"1.0","type":"link"}