{"product_id":"carrier-c48a803564-transformer-h301d7","title":"OEM Carrier Transformer 40VA 120V\/24V for C48A803564","description":"\u003ch1\u003eOEM Carrier Control Transformer 40VA 120V\/24V for Model C48A803564\u003c\/h1\u003e\u003cp\u003eThis OEM Carrier transformer (part number \u003cstrong\u003eHT01BD702\u003c\/strong\u003e) is the factory-specified replacement for the \u003cstrong\u003eC48A803564\u003c\/strong\u003e packaged unit. The transformer steps down line voltage from 120V to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When the transformer fails, nothing in the system responds: the thermostat goes blank, the unit won't call for heat or cooling, and you may find a blown fuse on the control board. If your system is completely unresponsive, the transformer is one of the first components to test.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | 120V primary \/ 24V secondary | OEM part number HT01BD702 | Factory-matched output for stable control voltage\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e This OEM transformer is wound to exact VA and voltage tolerances required by Carrier. Generic transformers frequently run under-rated VA, causing voltage sag under load — which leads to nuisance lockouts, contactor chatter, and premature control board failure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Disconnect power at the breaker and verify voltage is absent before starting. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label all wiring before removal and confirm primary\/secondary connections match your existing wiring diagram.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty. In-stock units ship the same business day from our warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed for the Carrier \u003cstrong\u003eC48A803564\u003c\/strong\u003e packaged unit. Verify your existing transformer's VA rating, primary voltage, and secondary voltage on the unit's wiring diagram or data plate before ordering. Our fitment team is available to confirm compatibility before you buy — same-day shipping on all in-stock orders.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909720789363,"sku":"CARRIE-C48A803564-TRANSFORMER-HT01BD702","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909720822131,"sku":"CARRIE-C48A803564-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_6289c8f3-d0d8-4541-81c9-ea5b885dd8f0.jpg?v=1782940291","url":"https:\/\/nationalhvacparts.com\/products\/carrier-c48a803564-transformer-h301d7","provider":"National HVAC Parts","version":"1.0","type":"link"}