{"product_id":"mcdonnell-miller-171802-150s-md-hi-press-level-control","title":"McDonnell \u0026 Miller 171802 150S-MD Low Water Cut-Off \u0026 Boiler Pump Controller (1 Inch NPT, Max Differential, 150 PSI)","description":"\u003ch2\u003eMcDonnell \u0026amp; Miller 171802 (Model 150S-MD) Combination Low Water Cut-Off \u0026amp; Pump Controller\u003c\/h2\u003e\n\u003cp\u003e\n  Engineered for primary or secondary low water fuel cut-off and automatic feed pump control on commercial and industrial steam boilers, the \n  \u003cstrong\u003eMcDonnell \u0026amp; Miller 171802 (Model 150S-MD)\u003c\/strong\u003e is a heavy-duty mechanical level controller designed for demanding high-temperature steam applications. Rated for operating steam pressures up to 150 PSI (10.5 kg\/cm²), this unit features a durable cast iron float chamber and heavy-duty Monel bellows construction for superior corrosion resistance and long operating life.\n\u003c\/p\u003e\n\u003cp\u003e\n  The \u003cstrong\u003e150S-MD\u003c\/strong\u003e model is factory-configured with a \u003cem\u003eMaximum Differential (MD)\u003c\/em\u003e operating profile, widening the switching distance between pump-off and burner-off settings to 1-3\/8\". This specialized differential setting compensates for setpoint shifts in low-pressure steam boilers (operating below 50 PSI), effectively eliminating rapid cycling and nuisance burner shutdowns caused by severe surging or rapidly fluctuating boiler water levels.\n\u003c\/p\u003e\n\n\u003ch4\u003eKey Performance \u0026amp; Construction Features:\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n    \u003cstrong\u003eMaximum Differential (MD) Tuning:\u003c\/strong\u003e Widened switching differential prevents rapid burner cycling and false trips in systems operating under 50 PSI.\n  \u003c\/li\u003e\n  \u003cli\u003e\n    \u003cstrong\u003eMonel Bellows Seal Isolation:\u003c\/strong\u003e Corrosion-resistant Monel bellows seal isolates mechanical switch linkages from harsh steam and boiler water environments.\n  \u003c\/li\u003e\n  \u003cli\u003e\n    \u003cstrong\u003eDual Heavy-Duty Snap Switches:\u003c\/strong\u003e Factory-equipped with one SPST snap switch for direct boiler feed pump activation and one SPDT switch for low water fuel cut-off and alarm signaling.\n  \u003c\/li\u003e\n  \u003cli\u003e\n    \u003cstrong\u003e1\" NPT Equalizing Tappings:\u003c\/strong\u003e Heavy-duty cast body with 1\" female threaded steam and water equalizing ports for solid pipe mounting directly to the boiler shell or external water column.\n  \u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\n  ⚠️ \u003cstrong\u003eApplication Profile:\u003c\/strong\u003e Recommended for commercial and industrial steam boilers of any steaming capacity requiring primary or secondary low water fuel cut-off, automated boiler feed pump control, or high\/low level alarm activation up to 150 PSI.\n\u003c\/p\u003e","brand":"McDonnell \u0026 Miller","offers":[{"title":"Default Title","offer_id":43041399930974,"sku":"MM-171802","price":1595.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0663\/7151\/8558\/files\/McDonnell_and_Miller_171802_150S-MD_Low_Water_Cut-Off_and_Boiler_Pump_Controller_1_Inch_NPT_150_PSI.jpg?v=1784749864","url":"https:\/\/nationalboilersupply.com\/products\/mcdonnell-miller-171802-150s-md-hi-press-level-control","provider":"National Boiler Supply","version":"1.0","type":"link"}