OEM Carrier Transformer 40VA 120V to 24V for Model FX4DNF031T00AAAA

This OEM replacement transformer (part# HT01CN241) is the factory-specified control transformer for the Carrier FX4DNF031T00AAAA air handler. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage safety circuits. When it fails, the entire control circuit goes dead — your thermostat goes blank, the system will not respond to any call for heating or cooling, and no error codes will display because the board itself has lost power.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN241 | Factory-matched impedance and thermal protection
• OEM vs Generic: This factory OEM unit is wound to exact VA and impedance tolerances for the FX4DNF031T00AAAA control circuit. Undersized or off-tolerance generic transformers can trip their thermal cutout repeatedly or fail to hold voltage under full contactor load, causing intermittent lockouts and premature control board failure.
• Install difficulty: 2/5 — Shut off all power at the breaker and air handler disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire nuts or spade terminals, multimeter. Photograph all low-voltage wiring connections before disconnecting. Verify 24V output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty against defects. In-stock units ship same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Designed specifically for the Carrier FX4DNF031T00AAAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltage on the unit data plate or transformer label before ordering. If your system shares a transformer with a furnace or heat pump control board, confirm load requirements have not changed. Our parts specialists are available to verify fitment before you order — no guesswork.