{"product_id":"carrier-ha1bjx030000adaa-transformer-h4oyjb","title":"OEM Carrier Transformer 40VA 120V\/24V for HA1BJX030000ADAA","description":"\u003ch1\u003eOEM Carrier Transformer 40VA 120V\/24V for Model HA1BJX030000ADAA\u003c\/h1\u003e\u003cp\u003eThis OEM replacement transformer (part number \u003cstrong\u003eHT01AW229\u003c\/strong\u003e) is the factory-specified control circuit transformer for the \u003cstrong\u003eCarrier HA1BJX030000ADAA\u003c\/strong\u003e. The transformer steps down 120V line voltage to the 24V signal voltage that powers your thermostat, control board, and all low-voltage components. When this part fails, the entire control circuit goes dead — the thermostat displays nothing, the system won't respond to any calls for heating or cooling, and no contactor or valve will activate. A failed transformer is often misdiagnosed as a thermostat or control board issue, so always confirm 24V output at the secondary terminals before replacing more expensive components.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | 120V primary \/ 24V secondary | Factory-matched OEM replacement | Part number HT01AW229 | Designed to Carrier factory tolerances\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM transformers are wound and insulated to exact factory specifications, ensuring stable 24V output under load. Generic units often deliver inconsistent voltage that can damage control boards and shorten component life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Shut off all power to the unit at the breaker before starting. Tools needed: flathead and Phillips screwdrivers, wire nuts or quick-connect terminals, multimeter to verify 24V output after installation. Always label wires before disconnecting and confirm polarity matches the original wiring diagram.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty. In stock and ships same business day from our warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed as a direct OEM replacement for Carrier model \u003cstrong\u003eHA1BJX030000ADAA\u003c\/strong\u003e. Verify your existing transformer's VA rating and primary\/secondary voltages on the unit's data plate or wiring diagram before ordering. Our team is available to confirm fitment prior to purchase — order today and get same-day shipping.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909363356019,"sku":"CARRIE-HA1BJX030000ADAA-TRANSFORMER-HT01AW229","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909363388787,"sku":"CARRIE-HA1BJX030000ADAA-TRANSFORMER-HT01AW229-GEN","price":18.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-HT01AW229_5646d095-608b-4a09-90b3-8bb9b3efef9e.jpg?v=1782941506","url":"https:\/\/nationalhvacparts.com\/products\/carrier-ha1bjx030000adaa-transformer-h4oyjb","provider":"National HVAC Parts","version":"1.0","type":"link"}