{"product_id":"carrier-fx4dnf031000aaaa-transformer-h3hwwy","title":"OEM Carrier Transformer 40VA 120V-24V for FX4DNF031000AAAA","description":"\u003ch1\u003eOEM Carrier Transformer 40VA 120V to 24V for Model FX4DNF031000AAAA\u003c\/h1\u003e\u003cp\u003eThis OEM Carrier transformer (part number \u003cstrong\u003eHT01CN241\u003c\/strong\u003e) is the factory-specified replacement for the \u003cstrong\u003eFX4DNF031000AAAA\u003c\/strong\u003e fan coil air handler. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, and all low-voltage switching components. When it fails, the entire control circuit goes dark — the thermostat displays nothing, the system won't respond to calls for heating or cooling, and in some cases a blown fuse or burning smell near the air handler is the first sign of trouble.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | 120V primary input | 24V secondary output | Factory-matched winding and thermal protection | Replaces OEM part number HT01CN241\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM transformers feature factory-wound coils and integrated thermal cutoffs matched to Carrier's control board draw. Generic units often lack adequate VA headroom, causing nuisance trips or premature burnout when multiple 24V accessories are wired in.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Disconnect power at the breaker and verify voltage is off before handling. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all low-voltage wire connections before removing the old transformer.\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 Engineered as a direct OEM replacement for the Carrier \u003cstrong\u003eFX4DNF031000AAAA\u003c\/strong\u003e fan coil air handler. Verify your existing transformer is rated 40VA 120V\/24V by checking the data label before ordering. If your control board fuse blew alongside the transformer, inspect for short circuits in the thermostat wiring before installing the new unit. Have a fitment question? Our HVAC parts team confirms compatibility before you order — call or chat today.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909477814643,"sku":"CARRIE-FX4DNF031000AAAA-TRANSFORMER-HT01CN241","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909477847411,"sku":"CARRIE-FX4DNF031000AAAA-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_e5ca21d8-b60f-4e91-be2a-0c4f25b03d5a.jpg?v=1782939677","url":"https:\/\/nationalhvacparts.com\/products\/carrier-fx4dnf031000aaaa-transformer-h3hwwy","provider":"National HVAC Parts","version":"1.0","type":"link"}