{"product_id":"carrier-hc1bnx042000aaaa-transformer-h4oyjb","title":"OEM Carrier Transformer 40VA 120V–24V for HC1BNX042000AAAA","description":"\u003ch1\u003eOEM Carrier Transformer 40VA 120V–24V for Model HC1BNX042000AAAA\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 HC1BNX042000AAAA\u003c\/strong\u003e fan coil unit. The transformer steps line voltage (120V) down to the 24V signal voltage required by the thermostat, control board, and all low-voltage components throughout the system. When this transformer fails, the entire control circuit loses power — the thermostat goes blank, the system refuses to respond to any calls for heating or cooling, and no contactors or relays will energize. It is often the first component to inspect when a system appears completely dead despite normal line voltage at the unit.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rated | 120V primary input | 24V secondary output | Factory-matched impedance and insulation class for Carrier HC1BNX042000AAAA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM transformers (HT01AW229) are wound to exact factory VA and thermal specifications. Generic substitutes often underrate VA capacity, causing premature thermal shutoff under full control-circuit load — particularly in multi-stage or communicating systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Confirm 0V at transformer terminals before handling. Photograph all wiring connections prior to removal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty against defects. In-stock and ships same business day from our HVAC parts warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed specifically for the Carrier \u003cstrong\u003eHC1BNX042000AAAA\u003c\/strong\u003e fan coil unit. Verify your existing transformer's VA rating and primary\/secondary voltages on the data plate before ordering. If you're unsure of fitment, our technical team is available to confirm compatibility before you purchase — same-day shipping available on all in-stock OEM parts.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909339468147,"sku":"CARRIE-HC1BNX042000AAAA-TRANSFORMER-HT01AW229","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909339500915,"sku":"CARRIE-HC1BNX042000AAAA-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_457a7c46-f20e-4add-80c8-6316b9aa0b62.jpg?v=1782941946","url":"https:\/\/nationalhvacparts.com\/products\/carrier-hc1bnx042000aaaa-transformer-h4oyjb","provider":"National HVAC Parts","version":"1.0","type":"link"}