{"product_id":"oem-lennox-dual-pressure-switch-assembly-33w18","title":"OEM Lennox Dual Pressure Switch Assembly — 33W18","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e33W18\u003c\/strong\u003e dual pressure switch assembly proves combustion draft by confirming the inducer motor has created adequate negative pressure before allowing ignition. Its dual-switch design monitors venting across firing stages, serving as an essential safety control in compatible Lennox gas furnaces to prevent operation under unsafe venting conditions.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e When this switch fails, the furnace typically will not ignite, locks out on a draft-proving fault, or short-cycles with a flashing error code. Symptoms include the inducer running with no burner ignition, repeated failed start attempts, and heat that stops shortly after firing due to a switch stuck open or reading improper pressure.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e The \u003cstrong\u003e33W18\u003c\/strong\u003e is factory-calibrated to the exact pressure setpoints your Lennox furnace was engineered for. Substituting a generic switch with the wrong trip rating risks nuisance lockouts or, worse, firing without confirmed safe venting. Installing the genuine OEM part ensures correct calibration, proper fit, and dependable, safe furnace operation.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081108570483,"sku":"LNX-33W18","price":24.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-pressure-switch-dual-LNX-33W18.jpg?v=1783760303","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-dual-pressure-switch-assembly-33w18","provider":"National HVAC Parts","version":"1.0","type":"link"}