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This OEM replacement transformer (part number HT01AW229) is the factory-specified control transformer for the Carrier HA1AJX048000AAAA packaged unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, contactor coil, gas valve, and all low-voltage control circuits. When it fails, the entire control system goes dark — the thermostat loses power, nothing responds, and the system will not heat or cool regardless of demand. A failed transformer is often the first diagnosis when absolutely nothing in the system responds.
Compatibility: Engineered specifically for the Carrier HA1AJX048000AAAA 4-ton packaged unit. Confirm your unit's control transformer VA rating and input voltage on the unit data plate before ordering. Our HVAC parts specialists are available to verify fitment — order with confidence and get back up and running today.