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This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C48A203552 packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage required to power the thermostat, control board, contactor coil, and all low-voltage control circuits. When this transformer fails, absolutely nothing in the control system responds — the thermostat goes blank, the system won't call for heating or cooling, and no fault codes appear because the board itself has no power.
Compatibility: Engineered for Carrier model C48A203552 packaged units. Confirm your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. If you're unsure whether this is the right part, our HVAC parts specialists verify fitment before you buy — no guesswork required. Order now and get same-day shipping on in-stock OEM parts.