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This is the factory OEM replacement transformer (part number HT01BD236) for the Carrier C4850C48ZW090610 packaged unit. The transformer steps line voltage (120V) down to the 24V signal voltage that powers your thermostat, control board, and all low-voltage switching components. When the 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 relays or contactors will energize. It is one of the first components to check when a unit shows absolutely zero response.
Compatibility: Designed as a direct OEM replacement for the Carrier C4850C48ZW090610 packaged unit. Always verify the 40VA rating and input/output voltage on your unit's data plate before ordering. If you need fitment confirmation, our parts specialists will verify compatibility before your order ships — same business day.