{"product_id":"carrier-transformer-fk4dnf001000aaaa","title":"OEM Carrier Transformer HT01BL233 for Model FK4DNF001000AAAA","description":"\u003cdiv\u003e\n\u003ch1\u003eOEM Carrier Transformer HT01BL233 for Model FK4DNF001000AAAA\u003c\/h1\u003e\n\u003cp\u003eThis genuine OEM Carrier control transformer (HT01BL233) steps line voltage down to the 24-volt control power that operates the thermostat, relays, and control board on your Carrier FK4DNF001000AAAA fan coil unit. The transformer underpins every heating and cooling cycle — a failure shuts down the entire low-voltage control system, producing a blank thermostat and a unit that will not respond or start. Blown transformers are a frequent, low-cost fix, usually caused by a brief short in the control wiring. This OEM replacement matches the FK4DNF001000AAAA's exact primary and secondary voltage and VA rating, supplying stable, correctly-rated 24V power that generic substitutes can't guarantee. Installation is moderate: with the power off, a technician transfers the primary and secondary leads, confirms the VA rating, and mounts it in roughly 20-30 minutes. Because it wires into line voltage, professional installation is recommended. We keep this transformer in stock and ship same-day on orders before 3PM CST. Restore reliable control-circuit operation fast with a genuine Carrier OEM transformer engineered for durability.\u003c\/p\u003e\n\u003ch2\u003eCompatibility\u003c\/h2\u003e\n\u003cp\u003eThis part is compatible with Carrier model FK4DNF001000AAAA.\u003c\/p\u003e\n\u003ch2\u003eShipping\u003c\/h2\u003e\n\u003cp\u003eSame-day shipping before 3 PM CST. 30-day returns on uninstalled parts.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Carrier","offers":[{"title":"Default Title","offer_id":62942921326963,"sku":"carrier-transformer-fk4dnf001000aaaa","price":34.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-carrier-transformer-fk_9f471e56-8e05-46b7-b0eb-862a0c69864b.jpg?v=1781473968","url":"https:\/\/nationalhvacparts.com\/products\/carrier-transformer-fk4dnf001000aaaa","provider":"National HVAC Parts","version":"1.0","type":"link"}