{"product_id":"oem-lennox-pressure-switch-51m86","title":"OEM Lennox Pressure Switch — 51M86","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e51M86\u003c\/strong\u003e pressure switch safeguards your furnace by verifying that the draft inducer has established proper venting before the burners are allowed to ignite. Through a sensing hose connected to the inducer, it monitors negative pressure and closes its contacts only when draft is adequate, giving the control board the proof-of-venting signal it needs to proceed. The \u003cstrong\u003e51M86\u003c\/strong\u003e is factory-calibrated to the precise pressure set point specified for your Lennox equipment.\u003c\/p\u003e\u003cp\u003eA worn or defective \u003cstrong\u003e51M86\u003c\/strong\u003e commonly causes a hard lockout with no heat, repeated short-cycling, or a furnace that clicks on and immediately shuts down. Symptoms can overlap with a clogged flue, condensate blockage, or failing inducer, so the switch and its hose should be checked as part of any draft-related diagnosis.\u003c\/p\u003e\u003cp\u003eChoosing OEM protects both performance and safety. The genuine Lennox \u003cstrong\u003e51M86\u003c\/strong\u003e carries the correct trip pressure for your model, ensuring the burners never fire without confirmed draft while avoiding false trips that leave you without heat. Generic replacements with the wrong calibration can create dangerous venting conditions or endless lockouts. Fit the factory \u003cstrong\u003e51M86\u003c\/strong\u003e for dependable, code-correct operation.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081103753587,"sku":"LNX-51M86","price":24.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-pressure-switch-single-LNX-51M86.jpg?v=1783763046","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-pressure-switch-51m86","provider":"National HVAC Parts","version":"1.0","type":"link"}