{"product_id":"carrier-fb4bnf018008aaaa-transformer-h3hwwy","title":"OEM Carrier Transformer 40VA 120V→24V for FB4BNF018008AAAA","description":"\u003ch1\u003eOEM Carrier Transformer 40VA 120V to 24V for Model FB4BNF018008AAAA\u003c\/h1\u003e\u003cp\u003eThis OEM Carrier transformer (part number \u003cstrong\u003eHT01CN241\u003c\/strong\u003e) is the factory-specified replacement for the \u003cstrong\u003eFB4BNF018008AAAA\u003c\/strong\u003e fan coil air handler. The transformer steps down line voltage from 120V to the 24V AC signal that powers the entire control circuit — including the thermostat, control board, and all low-voltage components. When this part fails, the system goes completely unresponsive: the thermostat goes dark, nothing calls for heating or cooling, and the unit will not operate in any mode. A blown transformer is often traced to a shorted low-voltage wire or a grounded thermostat terminal, so always inspect the secondary circuit before installing the replacement.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN241 | Factory-matched output tolerance for reliable control circuit operation\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. Generic units may fall short of rated VA output under load, causing intermittent lockouts, nuisance tripping, or 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 zero voltage with a multimeter before proceeding. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label all low-voltage wires before removing the old transformer and check for any shorted 24V wiring prior to energizing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our climate-controlled warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Engineered as a direct OEM replacement for Carrier model \u003cstrong\u003eFB4BNF018008AAAA\u003c\/strong\u003e fan coil air handlers. Always verify primary voltage (120V) and VA rating on your unit's data plate before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before every order — call or chat today and get your part shipped fast.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909541351795,"sku":"CARRIE-FB4BNF018008AAAA-TRANSFORMER-HT01CN241","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909541384563,"sku":"CARRIE-FB4BNF018008AAAA-TRANSFORMER-HT01CN241-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-HT01CN241_7ec3d6ee-3ab5-4b8e-bdca-c43e8b5499af.jpg?v=1782942027","url":"https:\/\/nationalhvacparts.com\/products\/carrier-fb4bnf018008aaaa-transformer-h3hwwy","provider":"National HVAC Parts","version":"1.0","type":"link"}