{"product_id":"allied-air-80w51-2-stage-pressure-switch-0-55-in-wc","title":"Allied Air 80W51 2-stage Pressure Switch 0.55 in Wc","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe ALLIED AIR 80W51 is a 2-stage pressure switch designed for use in gas furnace draft inducer control circuits. It monitors flue gas pressure to verify proper venting before allowing burner ignition, acting as a safety interlock within the furnace control sequence. The switch features a high set point of 0.55 inches water column (W.C.) and a low set point of 0.35 inches W.C., providing two-stage pressure sensing for furnaces that operate at both low-fire and high-fire stages. Licensed HVAC technicians install and service this component as part of routine furnace repair and maintenance work.\u003c\/p\u003e\n\u003cp\u003eThis pressure switch is used in residential gas furnaces that employ 2-stage heating operation. It is installed in the draft inducer circuit to confirm adequate negative pressure before energizing the gas valve. The 80W51 is also referenced under Lennox part number 104549-05, making it a relevant replacement candidate for techs servicing equipment under that cross-reference. Typical applications include induced-draft and forced-draft furnace platforms where dual set-point pressure monitoring is required.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e2-stage operation with high set point at 0.55 inches W.C. and low set point at 0.35 inches W.C.\u003c\/li\u003e\n  \u003cli\u003eFunctions as a safety interlock, preventing ignition if proper draft pressure is not established\u003c\/li\u003e\n  \u003cli\u003eCross-referenced to Lennox part number 104549-05\u003c\/li\u003e\n  \u003cli\u003eDesigned for induced-draft and forced-draft residential gas furnace applications\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eCross-referenced to Lennox part number 104549-05. Designed as an OEM-style replacement pressure switch for 2-stage residential gas furnaces requiring a high set point of 0.55 inches W.C. and a low set point of 0.35 inches W.C.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation and replacement of furnace pressure switches should be performed by a licensed HVAC technician. Disconnect power to the furnace and shut off the gas supply before beginning any service work. Verify that the replacement switch set points match the furnace manufacturer specifications before installing. Inspect the pressure switch hose and port for cracks, blockages, or moisture that could cause nuisance trips after installation.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\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\u003c\/strong\u003e: 0.55 inches W.C.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSet Point Low\u003c\/strong\u003e: 0.35 inches W.C.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\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: 80W51\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ALLIED AIR","offers":[{"title":"Default Title","offer_id":51284035764530,"sku":"80W51","price":48.28,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/309278052.png?v=1781066783","url":"https:\/\/voomisupply.com\/products\/allied-air-80w51-2-stage-pressure-switch-0-55-in-wc","provider":"Voomi Supply","version":"1.0","type":"link"}