OEM Carrier Control Transformer 40VA 120V/24V for Model C48A204064

This OEM replacement transformer (part number HT01BD702) is the factory-specified control circuit transformer for the Carrier C48A204064 packaged unit. The transformer steps down line voltage (120V) to the 24V AC signal required to power your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any calls for heating or cooling, and no contactors or valves will energize. It is often the first component to check when a unit is completely unresponsive despite having line voltage at the disconnect.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD702 | Factory-matched output tolerance for reliable low-voltage operation
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA rating and insulation class. Generic substitutes often have undersized VA ratings that overheat under full control-circuit load, causing nuisance tripping or premature failure.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Label or photograph all low-voltage wiring before disconnecting terminals.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A204064 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate or wiring diagram before ordering. If you're unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you purchase — same-day shipping available on all in-stock orders.