OEM Carrier 40VA Control Transformer for Model C4850C50AK03551

This is the factory OEM replacement control transformer (part# HT01BD236) for the Carrier C4850C50AK03551 packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage required by your thermostat, control board, contactor coil, and all low-voltage control circuits. When this component fails, the entire control circuit goes dead — your thermostat will go blank, the system will not respond to any calls for heating or cooling, and no fault codes will appear because the board itself has lost power.

• Specs: 40VA rated | 120V primary / 24V secondary | Class 2 transformer | OEM part number HT01BD236 | Direct factory-matched replacement
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA rating and insulation class. Undersized or off-spec generic transformers frequently overheat under the combined load of multiple 24V accessories (humidifiers, zone boards, UV lights), leading to premature failure and potential control board damage.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire nuts or spade connectors, multimeter. Label all wires before disconnecting. Verify 24V output with a multimeter after installation before closing the cabinet.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed as the direct OEM replacement for Carrier model C4850C50AK03551 packaged units. Cross-reference OEM part number HT01BD236 against your unit's wiring diagram or data plate to confirm fitment. If you are unsure whether this transformer matches your unit's VA or voltage requirements, our technical team is available to verify compatibility before you order — ensuring a correct first-time repair.