{"product_id":"oem-lennox-furnace-pressure-switch-49l90","title":"OEM Lennox Furnace Pressure Switch — 49L90","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e49L90\u003c\/strong\u003e pressure switch safeguards your furnace by verifying proper combustion airflow before ignition is permitted. It reads the negative pressure generated by the draft inducer motor and confirms that flue gases are venting correctly. When conditions are safe, the switch closes to allow the ignition sequence; when airflow is restricted or the inducer underperforms, it opens and locks out the burners to protect your home.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e A furnace that starts and immediately shuts off, repeated ignition lockouts, no heat despite the inducer running, or a diagnostic code pointing to the pressure switch. Blocked ports, a leaking sensing hose, or a fatigued internal diaphragm commonly trigger these faults.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Lennox calibrates each pressure switch to a model-specific trip point tied to the furnace's venting characteristics. A substitute with the wrong pressure rating can cause false lockouts or bypass an essential safety check. The OEM \u003cstrong\u003e49L90\u003c\/strong\u003e ensures the correct calibration, connector, and fit engineered for your Lennox equipment.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081104212339,"sku":"LNX-49L90","price":24.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-draft-inducer-LNX-49L90.jpg?v=1783761169","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-furnace-pressure-switch-49l90","provider":"National HVAC Parts","version":"1.0","type":"link"}