OEM Carrier Control Transformer 40VA 120V/24V for Model C48A502052

This OEM Carrier transformer (part number HT01BD236) is the factory-specified replacement for the C48A502052 packaged unit. The transformer steps down line voltage (120V) to the 24V control circuit voltage that powers your thermostat, contactor coil, and control board. When the transformer fails, the entire control circuit goes dark — the thermostat loses power, no calls for heating or cooling are processed, and the system appears completely unresponsive. A failed transformer is often misdiagnosed as a bad control board, making this an important first diagnostic step.

• Specs: 40VA rated | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched to Carrier C48A502052 electrical specifications
• OEM vs Generic: This OEM unit is wound to exact Carrier factory tolerances, ensuring stable 24V output under full load. Generic transformers frequently under-deliver VA capacity, causing voltage sag that damages contactors and control boards over time.
• Install difficulty: 2/5 — Shut off all power to the unit at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter, wire nuts. Always verify 0V at the transformer primary before touching any terminals. Label all low-voltage wiring before disconnecting.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our stocked warehouse.

Compatibility: Designed for the Carrier C48A502052 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the data plate before ordering. If you are unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you buy — same-day shipping on all in-stock orders.