OEM Carrier 40VA Control Transformer HT01BD236 for Model C4850C50Z3040600

This OEM control transformer (part number HT01BD236) is the factory-specified replacement for the Carrier C4850C50Z3040600 packaged unit. The transformer steps down 120V line voltage to the 24V AC signal required to power the thermostat, control board, contactor coil, and all low-voltage control components. When this transformer fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any calls for heating or cooling, and nothing operates despite power being present at the unit.

• Specs: Input 120V AC | Output 24V AC | 40VA rating | OEM part number HT01BD236 | Factory-matched winding and thermal protection
• OEM vs Generic: This OEM transformer meets Carrier's exact VA rating and insulation class specifications. Generic transformers often run undersized VA ratings, causing overheating and premature failure — particularly under heavy control circuit loads common in packaged units.
• Install difficulty: 2/5 — Shut off all power to the unit at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to verify 24V output after install). Label and photograph all wiring connections before disconnecting the old transformer. Swap wire-for-wire on primary and secondary terminals.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Fits Carrier model C4850C50Z3040600 packaged unit. Verify your existing transformer's input voltage, output voltage, and VA rating against your unit's data plate before ordering. If your control circuit repeatedly blows the transformer, inspect for shorts in the low-voltage wiring before installing a replacement. Our team is available to verify fitment — reach out before you order if you have any questions.