{"product_id":"oem-lennox-limit-switch-57w37","title":"OEM Lennox Limit Switch — 57W37","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e57W37\u003c\/strong\u003e limit switch is a high-temperature safety control used in Lennox gas furnaces to guard the heat exchanger against overheating. Positioned in the heated-air stream, it opens the control circuit and shuts off the gas valve when discharge-air temperature exceeds its factory set point — a condition usually triggered by low airflow from a clogged filter, weak blower motor, or blocked ductwork. It closes again automatically once the furnace cools.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e Repeated short-cycling, burners that ignite and then shut down after a minute or two, no heat while the blower continues to run, or an open-limit fault on the control board. A worn or out-of-calibration switch will interrupt normal heating cycles even when the furnace is operating properly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e The Lennox \u003cstrong\u003e57W37\u003c\/strong\u003e is engineered to the exact trip and reset thresholds your furnace requires. Substituting a generic switch with a different set point can cause nuisance lockouts or leave the heat exchanger unprotected. The factory-matched component ensures a proper fit and dependable safety response for your Lennox system.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081101132147,"sku":"LNX-57W37","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-57W37.jpg?v=1783762583","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-limit-switch-57w37","provider":"National HVAC Parts","version":"1.0","type":"link"}