{"product_id":"carrier-c4850c50ay05051-transformer-h302a1","title":"OEM Carrier Transformer 40VA 120V to 24V for C4850C50AY05051 | National HVAC Parts","description":"\u003ch1\u003eOEM Carrier 40VA Control Transformer HT01BD236 for Model C4850C50AY05051\u003c\/h1\u003e\u003cp\u003eThis OEM control transformer (part# \u003cstrong\u003eHT01BD236\u003c\/strong\u003e) is the factory-specified replacement for the \u003cstrong\u003eCarrier C4850C50AY05051\u003c\/strong\u003e packaged unit. The transformer steps down 120V line voltage to the 24V signal required by the thermostat, contactor coil, and all low-voltage control circuits. When it fails, the entire control system goes dark — the thermostat shows no power, the unit will not respond to any call for heating or cooling, and you may find a blown 3A or 5A fuse on the control board. A failed transformer is often misdiagnosed as a bad control board, so always check secondary voltage (should read 24–28VAC) before replacing more expensive components.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rating | Primary: 120VAC | Secondary: 24VAC | OEM part number HT01BD236 | Factory-matched winding tolerances for stable 24V output under full load\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e The OEM HT01BD236 transformer uses factory-spec copper windings and thermal overload protection rated for continuous HVAC duty. Generic transformers frequently under-deliver VA capacity, causing nuisance voltage drops that trigger false lockouts and shorten contactor coil life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Shut off power at the disconnect before starting. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Note primary and secondary wire colors before disconnecting, and verify secondary output reads 24–28VAC after installation before closing the panel.\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 Designed for the Carrier \u003cstrong\u003eC4850C50AY05051\u003c\/strong\u003e packaged unit. Verify the existing transformer's VA rating and primary\/secondary voltages on your unit's wiring diagram or data plate before ordering. If your unit has a 40VA transformer and runs on a standard 120V\/24V control circuit, this is a direct drop-in replacement. Have your model and serial number ready — our fitment team is available to confirm compatibility before you order.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62909808607603,"sku":"CARRIE-C4850C50AY05051-TRANSFORMER-HT01BD236","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62909808640371,"sku":"CARRIE-C4850C50AY05051-TRANSFORMER-HT01BD236-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-HT01BD236_67ffa43d-e2d9-4e74-93ec-d1203a80ee1f.jpg?v=1782938970","url":"https:\/\/nationalhvacparts.com\/products\/carrier-c4850c50ay05051-transformer-h302a1","provider":"National HVAC Parts","version":"1.0","type":"link"}