{"product_id":"carrier-fk4cnf003000agaa-transformer-h3hww2","title":"OEM Carrier Transformer 40VA 120V\/24V for FK4CNF003000AGAA","description":"\u003ch1\u003eOEM Carrier 40VA Control Transformer for Model FK4CNF003000AGAA\u003c\/h1\u003e\u003cp\u003eThis is the factory OEM replacement transformer (part number \u003cstrong\u003eHT01CN236\u003c\/strong\u003e) for the \u003cstrong\u003eCarrier FK4CNF003000AGAA\u003c\/strong\u003e fan coil unit. The transformer steps down 120V line voltage to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, nothing in the system responds: the thermostat goes blank, the air handler won't energize, and no heating or cooling call is processed. A faulty transformer is often the first suspect when a system goes completely dark with no error codes.\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 HT01CN236 | Factory-matched to Carrier FK4CNF003000AGAA fan coil specifications\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 the Carrier control circuit. Undersized or off-tolerance generic transformers can cause nuisance tripping, control board brownouts, and premature contactor coil failure — costing far more than the part itself.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Shut off all power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire strippers, multimeter. Verify 24V output at secondary terminals after installation before restoring full system power. Always label or photograph existing wiring before disconnecting.\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 warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed and factory-specified for the \u003cstrong\u003eCarrier FK4CNF003000AGAA\u003c\/strong\u003e fan coil unit. Confirm your existing transformer's VA rating and primary\/secondary voltages on the unit data plate before ordering. If you're unsure of fitment, our HVAC parts specialists verify compatibility before you buy — contact us with your model and serial number.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909499638131,"sku":"CARRIE-FK4CNF003000AGAA-TRANSFORMER-HT01CN236","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909499670899,"sku":"CARRIE-FK4CNF003000AGAA-TRANSFORMER-HT01CN236-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-HT01CN236_54cbee19-4d5e-4c6c-905b-2a852ef5494f.jpg?v=1782941086","url":"https:\/\/nationalhvacparts.com\/products\/carrier-fk4cnf003000agaa-transformer-h3hww2","provider":"National HVAC Parts","version":"1.0","type":"link"}