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This OEM control circuit transformer (part number HT01BC116) is the factory-specified replacement for the Carrier GA1AAD048070ABJA packaged gas/electric unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and every low-voltage component in the system. When the transformer fails, the entire control circuit goes dark — the thermostat goes blank, the system stops responding to any call for heating or cooling, and no components energize. It is one of the first parts to check when your system appears completely dead with no error codes.
Compatibility: Designed for the Carrier GA1AAD048070ABJA packaged unit. Always verify the transformer's VA rating and primary/secondary voltages against your unit's wiring diagram and data plate before ordering. If you are unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you purchase. In stock and ready to ship today — get your system back online fast.