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This is the factory OEM replacement transformer (part number HT01CN241) for the Carrier FB4CNP018000AAAA fan coil unit. The transformer steps down 120V line voltage to the 24V signal voltage required to power the control board, thermostat circuit, and all low-voltage switching components. When this transformer fails, the entire control circuit loses power — the thermostat goes blank, the system will not respond to any call for heating or cooling, and no low-voltage components will operate. A failed transformer is often misdiagnosed as a bad thermostat or control board, making it a critical first diagnostic step.
Compatibility: Engineered specifically for the Carrier FB4CNP018000AAAA fan coil unit. Verify your existing transformer's VA rating and input/output voltages against your unit's data plate before ordering. If your system uses a higher VA demand due to accessory loads (humidifiers, UV lights, zoning panels), consult our technical team before purchasing. Questions about fitment? Our HVAC parts specialists verify compatibility before you order — call or chat today.