{"product_id":"carrier-c48a804064-transformer-h301d7","title":"OEM Carrier Transformer 40VA 120V\/24V for C48A804064","description":"\u003ch1\u003eOEM Carrier 40VA Control Transformer HT01BD702 for Model C48A804064\u003c\/h1\u003e\u003cp\u003eThis OEM step-down transformer is the factory-specified replacement for the \u003cstrong\u003eCarrier C48A804064\u003c\/strong\u003e packaged unit. The transformer converts 120V line voltage to the 24V signal required by your thermostat, control board, contactor coil, and all low-voltage safety circuits. When it fails, the entire control circuit goes dead — the thermostat loses power, the system won't respond to any call for heating or cooling, and no fault codes appear because there's no voltage to generate them. If your unit is completely unresponsive and you've ruled out a blown fuse or tripped breaker, a failed transformer is the most common cause.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD702 | Factory-matched electrical tolerance for reliable low-voltage output\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM transformers are wound and insulated to Carrier's exact VA and voltage specifications. Undersized or off-spec generic units can overheat, blow the 3A control fuse repeatedly, or deliver unstable 24V that causes erratic thermostat and board behavior.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Shut off all power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, multimeter, needle-nose pliers. Photograph existing wiring connections before removal. Verify 24V output with a multimeter after installation before closing the cabinet.\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 Engineered for the Carrier \u003cstrong\u003eC48A804064\u003c\/strong\u003e packaged unit. Confirm your existing transformer's VA rating and primary\/secondary voltages on the unit data plate or transformer label before ordering. Cross-reference OEM part number \u003cstrong\u003eHT01BD702\u003c\/strong\u003e for guaranteed fitment. Have questions about compatibility? Our HVAC parts specialists verify fitment before you order — reach out before you buy.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909720691059,"sku":"CARRIE-C48A804064-TRANSFORMER-HT01BD702","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909720723827,"sku":"CARRIE-C48A804064-TRANSFORMER-HT01BD702-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-HT01BD702_7630f6da-3777-461a-ab2f-822132c2547a.jpg?v=1782940293","url":"https:\/\/nationalhvacparts.com\/products\/carrier-c48a804064-transformer-h301d7","provider":"National HVAC Parts","version":"1.0","type":"link"}