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This OEM replacement contactor is the factory-specified part for the Carrier CP50P550P503521CP packaged unit. The contactor is a high-voltage relay that receives a 24V signal from the thermostat and closes the circuit to send line voltage to the compressor and condenser fan motor. When it fails, the most common symptoms include the AC unit not turning on at all, the compressor failing to engage despite the thermostat calling for cooling, or the contactor staying stuck in the closed position causing the system to run continuously without cycling off.
Compatibility: Engineered specifically for the Carrier CP50P550P503521CP packaged unit. Cross-reference OEM part number HN53CD115 against your unit's data plate and existing contactor label to confirm pole count, coil voltage, and amperage rating before ordering. Not sure if this is the right part? Our HVAC parts specialists verify fitment before you buy — contact us and we'll confirm compatibility fast.