OEM Carrier Control Transformer 40VA 120V/24V for Model C48A302764

This OEM replacement transformer (part number HT01BD702) is the factory-specified step-down transformer for the Carrier C48A302764 packaged unit. The transformer converts 120V line voltage to the 24V control circuit voltage that powers your thermostat, contactor coil, gas valve, and all low-voltage control signals. When this component fails, the entire control circuit goes dark — symptoms include a completely unresponsive thermostat, a system that won't respond to any call for heating or cooling, or a tripped low-voltage fuse with no obvious cause.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD702 | Factory-matched output tolerance for reliable control circuit performance
• OEM vs Generic: OEM transformers are wound to exact factory VA and voltage specs, ensuring stable 24V output under full control circuit load. Generic units frequently under-deliver VA capacity, causing nuisance lockouts, erratic thermostat behavior, and premature contactor coil failure.
• Install difficulty: 2/5 — Disconnect all power to the unit before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to confirm 24V output after install). Photograph all low-voltage wiring connections before disconnecting. Always check the low-voltage fuse before replacing the transformer — a shorted load can blow a new transformer immediately.
• Warranty: 1-year OEM factory warranty. In-stock units ship same business day from our warehouse.

Compatibility: This transformer is the OEM factory replacement for the Carrier C48A302764 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering to confirm fitment. Our parts specialists are available to verify compatibility before you purchase — reach out before you order if you have any questions, and we'll ship your part the same business day.