OEM Carrier Control Transformer 40VA 120V/24V for Model C50A402551

This is the OEM factory-specified control transformer (part number HT01BD236) for the Carrier C50A402551 packaged unit. The transformer steps down 120V line voltage to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When this transformer fails, the entire control circuit goes dead: the thermostat goes blank, nothing responds, and the system will not start in any mode. It is often the first component to check when a system shows zero control-side activity.

• Specs: 40VA capacity | 120V primary / 24V secondary | Step-down control transformer | OEM part number HT01BD236 | Factory-matched output for Carrier low-voltage circuits
• OEM vs Generic: The OEM HT01BD236 transformer is wound to exact VA and voltage tolerances required by the Carrier C50A402551 control board. Generic transformers may deliver slightly off-voltage output under load, causing nuisance tripping, board resets, or premature contactor coil failure.
• Install difficulty: 2/5 — Disconnect power at the disconnect box and verify zero voltage with a multimeter before beginning work. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label all wires before disconnecting and inspect for any short circuit that may have caused the original failure — replacing a transformer without clearing the fault will blow the new unit immediately.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM replacement for Carrier model C50A402551 packaged units. Verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering. If you're unsure about fitment, our parts team will verify compatibility before you buy — no guesswork required.