{"product_id":"oem-lennox-furnace-limit-switch-19j81","title":"OEM Lennox Furnace Limit Switch — 19J81","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e19J81\u003c\/strong\u003e limit switch is a temperature-activated safety control for your Lennox gas furnace. Positioned to sense heat exchanger or plenum temperature, it interrupts the gas valve circuit whenever the furnace exceeds its safe operating temperature — guarding against a cracked heat exchanger, overheated components, and the fire hazards that come with an over-firing furnace. It's manufactured to the precise trip point Lennox specifies for the 19J81 application.\u003c\/p\u003e\u003cp\u003eSigns of a failing limit switch include a furnace that short-cycles, shuts down prematurely before satisfying the thermostat, repeatedly trips on high limit, or won't light because the switch has failed open. A switch stuck closed is especially dangerous, since it removes the furnace's overheat protection entirely.\u003c\/p\u003e\u003cp\u003eUsing the OEM \u003cstrong\u003e19J81\u003c\/strong\u003e is essential for safety and reliability. The switch's temperature calibration is matched to your furnace's specific design; an off-spec aftermarket part can nuisance-trip or fail to protect at the correct threshold. Installing the factory limit switch restores dependable heat and proper high-temperature safety.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081113583987,"sku":"LNX-19J81","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-19J81.jpg?v=1783761132","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-furnace-limit-switch-19j81","provider":"National HVAC Parts","version":"1.0","type":"link"}