{"product_id":"oem-lennox-pressure-switch-59w74","title":"OEM Lennox Pressure Switch — 59W74","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e59W74\u003c\/strong\u003e pressure switch is a critical safety control that confirms proper venting and combustion airflow before your furnace ignites. By sensing the negative pressure created by the draft inducer, it verifies that flue gases can be safely exhausted — and it will prevent ignition if adequate draft is not detected, protecting your home from dangerous combustion conditions.\u003c\/p\u003e\u003cp\u003eA faulty or failing pressure switch commonly causes the furnace to lock out, short cycle, or fail to light at all, often paired with an ignition-related fault code on the control board. Blocked vents, a weak inducer, or cracked tubing can also trigger it — but a switch that sticks open or closed, or drifts out of calibration, will need replacement to restore reliable operation.\u003c\/p\u003e\u003cp\u003eThe OEM Lennox \u003cstrong\u003e59W74\u003c\/strong\u003e is factory-calibrated to the exact pressure setpoint your furnace model requires. Aftermarket switches with the wrong trip point can either nuisance-trip or, worse, fail to protect against unsafe conditions. Choosing genuine Lennox ensures correct calibration, proper fit, and continued safe, code-compliant operation.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081100771699,"sku":"LNX-59W74","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-59W74.jpg?v=1783763066","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-pressure-switch-59w74","provider":"National HVAC Parts","version":"1.0","type":"link"}