{"product_id":"oem-lennox-limit-switch-18k43","title":"OEM Lennox Limit Switch — 18K43","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e18K43\u003c\/strong\u003e limit switch is an essential safety device in your Lennox heating system. It monitors the temperature around the heat exchanger and opens the burner circuit whenever heat exceeds the safe threshold, preventing damage from overheating and restoring operation once conditions cool. This direct factory replacement delivers the exact fit and calibrated trip point your furnace requires.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e When the \u003cstrong\u003e18K43\u003c\/strong\u003e goes bad, typical signs include the furnace failing to produce heat, short-cycling on and off, the blower motor running continuously, or the system locking out after repeated trips. A limit switch that opens too early causes frustrating intermittent heating, while one stuck closed removes a vital layer of protection.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Lennox designs each limit switch, including the \u003cstrong\u003e18K43\u003c\/strong\u003e, with a precise temperature rating suited to its specific furnace platform. Off-brand parts with mismatched thresholds can trigger false shutdowns or leave your equipment unprotected. The authentic OEM component restores the exact safety behavior Lennox intended, keeping your furnace operating safely and efficiently for years to come.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081114009971,"sku":"LNX-18K43","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-18K43.jpg?v=1783762467","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-limit-switch-18k43","provider":"National HVAC Parts","version":"1.0","type":"link"}