OEM Carrier Control Transformer 40VA 120V to 24V for Model C48A703564

This OEM replacement transformer (part number HT01BD702) is the factory-specified step-down transformer for the Carrier C48A703564 packaged unit. Its job is to convert 120V line voltage down to the 24V signal voltage that powers your thermostat, control board, contactor coil, and every other low-voltage component in the system. When this transformer fails, the entire control circuit goes dark — your thermostat goes blank, the system becomes completely unresponsive, and no heating or cooling function is possible.

• Specs: 40VA rated capacity | 120V primary / 24V secondary | Class 2 transformer | Factory-matched OEM part number HT01BD702 | Designed for Carrier packaged unit control circuits
• OEM vs Generic: OEM transformers are wound and insulated to Carrier's exact specifications, ensuring proper VA capacity and long-term thermal stability. Undersized or off-brand transformers can overheat under normal load, blow internal fuses, and take downstream components with them.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire stripper, and a multimeter to confirm 24V output after installation. Label or photograph existing wiring before disconnecting the old unit.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our stocked warehouse.

Compatibility: This transformer is engineered specifically for the Carrier C48A703564 packaged unit. Before ordering, verify the VA rating and primary/secondary voltages on your unit's wiring diagram or data plate. If you're unsure of fitment, our HVAC parts specialists confirm compatibility before you buy — no guesswork, no returns.