{"product_id":"carrier-pf4mna025t00aaaa-transformer-h3hwwy","title":"OEM Carrier 40VA Transformer 120V–24V for PF4MNA025T00AAAA","description":"\u003ch1\u003eOEM Carrier 40VA Control Transformer 120V\/24V for Model PF4MNA025T00AAAA\u003c\/h1\u003e\u003cp\u003eThis is the factory OEM replacement transformer (part number \u003cstrong\u003eHT01CN241\u003c\/strong\u003e) for the \u003cstrong\u003eCarrier PF4MNA025T00AAAA\u003c\/strong\u003e air handler. The transformer steps down 120V line voltage to the 24V signal used by the thermostat, control board, and all low-voltage control circuits. When this transformer fails, the entire control circuit goes dead — no thermostat response, no blower operation, and no heating or cooling, even though line power is present. A shorted low-voltage wiring harness is frequently the root cause of transformer failure, so inspect all 24V wiring before replacing the part.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 120V primary \/ 24V secondary | 40VA output rating | Carrier 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 This OEM transformer is wound to Carrier's exact VA and voltage tolerances. Generic units often use undersized cores that overheat and fail prematurely — especially when connected to modern communicating thermostats that draw higher standby current.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Turn off all power at the breaker before beginning. Tools needed: flat-head and Phillips screwdrivers, multimeter, wire nuts. Verify 24V output at the secondary leads with a multimeter before reassembly. Always check low-voltage wiring for shorts prior to energizing the new transformer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty. Ships 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\u003ePF4MNA025T00AAAA\u003c\/strong\u003e air handler. Verify your existing transformer's VA rating and primary\/secondary voltages on the unit's data plate before ordering. Our team is available to confirm fitment — reach out before you order if you have any questions.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62643311477107,"sku":"CARRIE-PF4MNA025T00AAAA-TRANSFORMER-HT01CN241","price":33.95,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62643311509875,"sku":"CARRIE-PF4MNA025T00AAAA-TRANSFORMER-HT01CN241-GEN","price":29.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-HT01CN241_ce83fed2-4c27-49bf-8f88-513896475680.jpg?v=1775016342","url":"https:\/\/nationalhvacparts.com\/products\/carrier-pf4mna025t00aaaa-transformer-h3hwwy","provider":"National HVAC Parts","version":"1.0","type":"link"}