{"product_id":"carrier-fb4cnp018000aaaa-transformer-h3hwwy","title":"OEM Carrier Transformer 40VA 120V-24V for FB4CNP018000AAAA","description":"\u003ch1\u003eOEM Carrier Transformer 40VA 120V to 24V for Model FB4CNP018000AAAA\u003c\/h1\u003e\u003cp\u003eThis is the factory OEM replacement transformer (part number \u003cstrong\u003eHT01CN241\u003c\/strong\u003e) for the \u003cstrong\u003eCarrier FB4CNP018000AAAA\u003c\/strong\u003e fan coil unit. The transformer steps down 120V line voltage to the 24V signal voltage required to power the control board, thermostat circuit, and all low-voltage switching components. When this transformer fails, the entire control circuit loses power — the thermostat goes blank, the system will not respond to any call for heating or cooling, and no low-voltage components will operate. A failed transformer is often misdiagnosed as a bad thermostat or control board, making it a critical first diagnostic step.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | 120V primary \/ 24V secondary | Factory OEM part number HT01CN241 | Engineered to exact Carrier tolerances for stable low-voltage output\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e OEM transformers maintain consistent 24V output under variable load conditions. Generic alternatives frequently produce voltage sag under full load, causing intermittent lockouts, nuisance trips, 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 before beginning any work. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or quick-connect terminals. Verify primary and secondary voltages with a multimeter before and after installation. Always confirm 24V output is stable under load before closing the cabinet.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty. 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 specifically for the Carrier \u003cstrong\u003eFB4CNP018000AAAA\u003c\/strong\u003e fan coil unit. Verify your existing transformer's VA rating and input\/output voltages against your unit's data plate before ordering. If your system uses a higher VA demand due to accessory loads (humidifiers, UV lights, zoning panels), consult our technical team before purchasing. Questions about fitment? Our HVAC parts specialists verify compatibility before you order — call or chat today.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909534699891,"sku":"CARRIE-FB4CNP018000AAAA-TRANSFORMER-HT01CN241","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909534732659,"sku":"CARRIE-FB4CNP018000AAAA-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_adedf396-993d-4f06-87ec-b59cd47d64f8.jpg?v=1782939540","url":"https:\/\/nationalhvacparts.com\/products\/carrier-fb4cnp018000aaaa-transformer-h3hwwy","provider":"National HVAC Parts","version":"1.0","type":"link"}