OEM Carrier Transformer 40VA 120V/24V for Model C4850C50AY02051

This is the OEM factory-specified control transformer (part number HT01BD236) for the Carrier C4850C50AY02051 packaged unit. The transformer steps down line voltage from 120V to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, the entire control circuit goes dead: your thermostat loses power, the system will not respond to any call for heating or cooling, and in some cases a blown fuse on the control board may be the first visible symptom. Replacing this part is one of the most cost-effective repairs in the field.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM part number HT01BD236 | Direct plug-and-play replacement for factory-installed unit
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA and voltage specifications. Generic transformers can underperform under full control-circuit load, causing nuisance tripping, blown fuses, or erratic thermostat behavior — especially in systems with zone boards or multiple accessories drawing 24V power.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify with a multimeter before starting. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade connectors, multimeter. Label or photograph all wiring before disconnecting. Check and replace the 3A or 5A control fuse if blown before energizing the new transformer.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse when ordered before 3PM local time.

Compatibility: Engineered specifically for the Carrier C4850C50AY02051 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate or wiring diagram before ordering. Our HVAC parts specialists are available to confirm fitment — just reach out before you buy. In stock and ready to ship today.