OEM Carrier Transformer 40VA 120V/24V for Model C4850C48AY05161

This is the factory-specified OEM replacement transformer (part number HT01BD236) for the Carrier C4850C48AY05161 packaged unit. The transformer steps down 120V line voltage to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, the system becomes completely unresponsive: the thermostat goes blank, the contactor won't pull in, and no heating or cooling function is possible. A blown transformer is often caused by a short in the 24V control wiring, so inspect all low-voltage wiring before installing the replacement.

• Specs: Input 120VAC | Output 24VAC | 40VA rating | OEM part number HT01BD236 | Factory-matched impedance and thermal protection
• OEM vs Generic: The OEM HT01BD236 transformer is wound and rated to exact factory specifications. Generic transformers often use lighter gauge windings and lack integrated thermal cutoffs, making them prone to early failure — especially under high-demand control circuit loads.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade connectors, multimeter to verify 24V output after install. Always check for low-voltage short circuits before energizing the new transformer.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier C4850C48AY05161 packaged unit. Verify your existing transformer's input/output voltage and VA rating on the data plate before ordering. Our HVAC parts specialists are available to confirm fitment — order with confidence.