{"product_id":"oem-lennox-limit-switch-79j89","title":"OEM Lennox Limit Switch — 79J89","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e79J89\u003c\/strong\u003e limit switch is a temperature-sensing safety control that monitors heat in your furnace's heat exchanger and plenum. If temperatures climb above a safe threshold — usually from restricted airflow — the switch opens and shuts off the gas burners to prevent overheating and heat-exchanger damage.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e the furnace short-cycles on high heat, the blower runs constantly, no heat with a limit or lockout fault code, or burners that light and quickly cut out. A switch that has drifted out of calibration or failed open will stop the furnace even when conditions are normal, while a dirty filter or blocked duct can also trip a healthy switch.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e the \u003cstrong\u003e79J89\u003c\/strong\u003e is calibrated to the precise trip and reset temperatures your specific Lennox furnace requires and mounts to match its exact location. A mismatched aftermarket limit can trip too early, too late, or fail to protect the heat exchanger at all. Installing the factory OEM switch restores correct safety operation and reliable heating for your Lennox system.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081094971763,"sku":"LNX-79J89","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-79J89.jpg?v=1783762614","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-limit-switch-79j89","provider":"National HVAC Parts","version":"1.0","type":"link"}