{"product_id":"carrier-fx4dnf043t10aaaa-transformer-h3hwwy","title":"OEM Carrier Transformer 40VA 120V\/24V for FX4DNF043T10AAAA","description":"\u003ch1\u003eOEM Carrier Transformer 40VA 120V to 24V for Model FX4DNF043T10AAAA\u003c\/h1\u003e\u003cp\u003eThis OEM replacement transformer (part number \u003cstrong\u003eHT01CN241\u003c\/strong\u003e) is the factory-specified control circuit transformer for the \u003cstrong\u003eCarrier FX4DNF043T10AAAA\u003c\/strong\u003e fan coil air handler. Its sole but critical job is to step line voltage (120V) down to 24V AC, powering the thermostat, control board, and every low-voltage relay in the system. When this transformer fails, absolutely nothing responds — the thermostat goes blank, the system will not heat or cool, and the air handler sits completely silent. A failed transformer is often misdiagnosed as a bad control board, making correct identification essential before spending more.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN241 | Factory-matched output tolerance for stable low-voltage circuit operation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-tolerance generic units can cause nuisance tripping of the fuse on the control board or premature board failure — use OEM to protect the entire system.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or terminal connectors. Verify output voltage (24V AC) with a multimeter after installation before restoring the system to operation.\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 warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed for the Carrier \u003cstrong\u003eFX4DNF043T10AAAA\u003c\/strong\u003e fan coil air handler. Verify your existing transformer's VA rating and primary\/secondary voltages against your unit's wiring diagram and data plate before ordering. If you need fitment confirmation, our HVAC parts specialists are available to verify compatibility before you buy.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909473194355,"sku":"CARRIE-FX4DNF043T10AAAA-TRANSFORMER-HT01CN241","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909473227123,"sku":"CARRIE-FX4DNF043T10AAAA-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_80f24c82-f4e9-4ebc-a838-d0aeea18353e.jpg?v=1782941232","url":"https:\/\/nationalhvacparts.com\/products\/carrier-fx4dnf043t10aaaa-transformer-h3hwwy","provider":"National HVAC Parts","version":"1.0","type":"link"}