{"product_id":"allied-air-14a51-2-stage-pressure-switch","title":"Allied Air 14A51 2-stage Pressure Switch","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe ALLIED AIR 14A51 is a 2-stage pressure switch designed for gas furnace applications. It monitors flue gas pressure to verify that the inducer motor is operating correctly before allowing ignition to proceed. With a high-stage set point of 0.74 inches water column (W.C.) and a low-stage set point of 0.41 inches W.C., this switch provides two-stage protection that matches the operating demands of two-stage gas furnace systems. Licensed HVAC technicians install this switch as a safety control component during routine maintenance or diagnosis of pressure-related lockout conditions.\u003c\/p\u003e\u003cp\u003eThis pressure switch is used in residential two-stage gas furnace installations where the furnace control board requires separate pressure confirmation signals for low-fire and high-fire operation. The 14A51 carries a cross-reference to Lennox part number 104549-09, making it a recognized replacement option in service situations where that part number is called out on a wiring diagram or parts list.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eTwo-stage design with independent high-stage (0.74 inches W.C.) and low-stage (0.41 inches W.C.) set points\u003c\/li\u003e\n\u003cli\u003eFunctions as a safety interlock to prevent ignition when inducer airflow is insufficient\u003c\/li\u003e\n\u003cli\u003eCross-references to Lennox 104549-09 for service identification\u003c\/li\u003e\n\u003cli\u003eSuitable for residential two-stage gas furnace systems\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eCross-references to Lennox part number 104549-09. Designed as an OEM-style replacement for two-stage residential gas furnace pressure switch applications where that part number is specified.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eA licensed HVAC technician should perform pressure switch replacement. Power down the furnace and disconnect electrical supply before beginning work. Verify inducer operation and check flue and drain tubing for blockages or cracks before installing the new switch, as these conditions are a common root cause of pressure switch failures. Follow local mechanical codes and the furnace manufacturer's service instructions throughout the replacement procedure.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSwitch Type\u003c\/strong\u003e: 2-Stage Pressure Switch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSet Point High Stage\u003c\/strong\u003e: 0.74 inches W.C.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSet Point Low Stage\u003c\/strong\u003e: 0.41 inches W.C.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: ALLIED AIR\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 14A51\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ALLIED AIR","offers":[{"title":"Default Title","offer_id":51283909443890,"sku":"14A51","price":58.02,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/309277553.png?v=1781063013","url":"https:\/\/voomisupply.com\/products\/allied-air-14a51-2-stage-pressure-switch","provider":"Voomi Supply","version":"1.0","type":"link"}