{"product_id":"payne-pa12na01800gaaaa-pressure-switch-jria74","title":"OEM Payne Pressure Switch HK02ZA395 \/ HK02ZB028 — PA12NA01800GAAAA","description":"\u003ch1\u003eOEM Payne High \u0026amp; Low Pressure Switch for Model PA12NA01800GAAAA\u003c\/h1\u003e\u003cp\u003eThese OEM pressure switches — \u003cstrong\u003eHK02ZA395 (High Pressure Switch)\u003c\/strong\u003e and \u003cstrong\u003eHK02ZB028 (Low Pressure Switch)\u003c\/strong\u003e — are the factory-specified replacements for the \u003cstrong\u003ePayne PA12NA01800GAAAA\u003c\/strong\u003e gas furnace. Pressure switches monitor the negative pressure (draft) created by the inducer motor, proving that combustion airflow is safe before allowing ignition to proceed. When either switch fails, the control board will lock out the ignition sequence entirely, leaving you with a no-heat condition even though the inducer motor is running normally.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e HK02ZA395 — High-stage pressure switch | HK02ZB028 — Low-stage pressure switch | 24V control circuit | Factory-calibrated W.C. (water column) rating matched to the PA12NA01800GAAAA inducer assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM pressure switches use factory-calibrated diaphragms and W.C. set points. Aftermarket substitutes frequently carry loose tolerances that cause nuisance trips or, worse, allow ignition under unsafe draft conditions — a serious safety risk on any gas appliance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 3\/5\u003c\/strong\u003e — Power down and lock out the furnace before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, manometer (recommended for set-point verification), and a multimeter for continuity testing. Photograph all tubing and wiring connections before removal. Check the rubber hose and port for blockage or cracks while the switch is out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty on both switches. Orders placed by 3 PM ship same business day from our warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Engineered specifically for the \u003cstrong\u003ePayne PA12NA01800GAAAA\u003c\/strong\u003e gas furnace. Always cross-reference OEM part numbers HK02ZA395 and HK02ZB028 against your unit's data plate and wiring diagram before ordering to confirm correct high- or low-stage switch selection. Have questions about fitment? Our HVAC parts specialists verify compatibility before you buy — contact us before placing your order.\u003c\/p\u003e","brand":"Payne","offers":[{"title":"OEM","offer_id":62909207445875,"sku":"PAYNE-PA12NA01800GAAAA-PRESSURE_SWITCH-HK02ZA395","price":43.95,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909207478643,"sku":"PAYNE-PA12NA01800GAAAA-PRESSURE_SWITCH-HK02ZA395-GEN","price":38.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-pressure-switch-HK02ZA395_f647e7c9-3ce2-403d-b104-9b16629bbb1e.jpg?v=1780718537","url":"https:\/\/nationalhvacparts.com\/products\/payne-pa12na01800gaaaa-pressure-switch-jria74","provider":"National HVAC Parts","version":"1.0","type":"link"}