{"product_id":"oem-lennox-limit-switch-51m75","title":"OEM Lennox Limit Switch — 51M75","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e51M75\u003c\/strong\u003e limit switch is a critical safety component in your furnace's heat exchanger circuit. It continuously monitors plenum temperature and cuts power to the burners if the system overheats, protecting your heat exchanger and household from dangerous conditions. This factory-spec switch is engineered to the exact temperature trip and reset points your Lennox equipment requires.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e When the \u003cstrong\u003e51M75\u003c\/strong\u003e fails or drifts out of calibration, you may notice short-cycling (the furnace repeatedly firing and shutting off), no heat despite the blower running, or a unit that trips on limit and locks out. A cracked or worn switch can also cause intermittent operation that's hard to diagnose.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Aftermarket limit switches often trip at incorrect temperatures, which either allows unsafe overheating or causes nuisance shutdowns. The OEM Lennox \u003cstrong\u003e51M75\u003c\/strong\u003e guarantees the correct trip setpoint, terminal configuration, and mechanical fit for a reliable, code-compliant repair that keeps your Lennox furnace running safely.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081103786355,"sku":"LNX-51M75","price":19.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-limit-switch-snap-disc-LNX-51M75.jpg?v=1783762568","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-limit-switch-51m75","provider":"National HVAC Parts","version":"1.0","type":"link"}