{"product_id":"carrier-ha1ajx018000abaa-pressure-switch-jrhhwm","title":"OEM Carrier Low Pressure Switch HK02ZB028 for HA1AJX018000ABAA","description":"\u003ch1\u003eOEM Carrier Low Pressure Switch HK02ZB028 for Model HA1AJX018000ABAA\u003c\/h1\u003e\u003cp\u003eThis OEM low pressure switch (part number \u003cstrong\u003eHK02ZB028\u003c\/strong\u003e) is the factory-specified replacement for the \u003cstrong\u003eCarrier HA1AJX018000ABAA\u003c\/strong\u003e. The pressure switch is a critical safety component that monitors the negative pressure (vacuum) created by the inducer draft motor to confirm proper venting before allowing the ignition sequence to proceed. When this switch fails or sticks open, the control board never receives the \"inducer proven\" signal, resulting in a no-heat lockout condition — often with a blinking fault code indicating a pressure switch error.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e Low pressure switch | OEM part number HK02ZB028 | Factory-calibrated W.C. (water column) rating | Normally open (NO) single-port configuration | Direct factory replacement\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM pressure switches are precision-calibrated to the exact water column rating required for your specific inducer and heat exchanger. Off-brand substitutes with loose tolerances can fail to prove the inducer correctly — creating unsafe nuisance lockouts or, worse, allowing ignition under inadequate draft conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 3\/5\u003c\/strong\u003e — Disconnect power before servicing. Tools needed: 1\/4\" nut driver, flathead screwdriver, manometer (recommended for verification), and needle-nose pliers for hose clamps. Inspect the rubber pressure port hose for cracks or blockages before installing the new switch, as a damaged hose is a common root cause of switch failure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty against defects. In-stock units ship same business day when ordered before cutoff.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed specifically for the Carrier \u003cstrong\u003eHA1AJX018000ABAA\u003c\/strong\u003e. Always cross-reference the W.C. rating stamped on your existing switch and verify against your unit's wiring diagram before ordering. If you're unsure of fitment, our HVAC parts specialists can confirm compatibility before you purchase — same-day shipping available on all stocked OEM parts.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909371351411,"sku":"CARRIE-HA1AJX018000ABAA-PRESSURE_SWITCH-HK02ZB028","price":27.0,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909371384179,"sku":"CARRIE-HA1AJX018000ABAA-PRESSURE_SWITCH-HK02ZB028-GEN","price":19.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-draft-inducer-HK02ZB028.jpg?v=1782928655","url":"https:\/\/nationalhvacparts.com\/products\/carrier-ha1ajx018000abaa-pressure-switch-jrhhwm","provider":"National HVAC Parts","version":"1.0","type":"link"}