OEM Carrier 40VA Control Transformer HT01CN241 for Model FX4DNF019000AAAA

This is the factory OEM replacement transformer (part number HT01CN241) for the Carrier FX4DNF019000AAAA air handler. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and every other low-voltage component in the system. When it fails, the entire control circuit goes dark — your thermostat shows a blank screen, the system refuses to respond to any call for heating or cooling, and no error codes can even be generated. It is one of the most overlooked yet most critical components in any air handler.

• Specs: 40VA rating | 120V primary / 24V secondary | Single-phase | Factory-matched impedance and insulation class for the FX4DNF019000AAAA platform
• OEM vs Generic: The OEM HT01CN241 is wound and rated specifically for Carrier's control board current draw. Generic transformers often use undersized VA ratings that sag under load, causing intermittent lockouts, nuisance thermostat resets, and premature control board failure.
• Install difficulty: 2/5 — Shut off power at the breaker and disconnect the air handler before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire nuts or terminal connectors, multimeter to confirm 24V output after installation. Label all low-voltage wires before removal.
• Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier FX4DNF019000AAAA fan coil air handler. Always verify your existing transformer's VA rating and voltage markings on the unit data plate before ordering to ensure a correct match. Have questions about fitment? Our HVAC parts specialists confirm compatibility before you order — no guesswork required.