OEM Carrier 40VA Control Transformer for Model FX4DNF043000ABAA Air Handler

This is the OEM factory-replacement control transformer (part# HT01CN241) for the Carrier FX4DNF043000ABAA fan coil air handler. The transformer steps down 120V line voltage to the 24V signal used by your thermostat, control board, contactor coil, and zone controls. When it fails, the entire low-voltage control circuit goes dead — your thermostat goes blank, the system won't respond to any call for heating or cooling, and no fault codes will display. If you've confirmed 120V at the primary but zero volts at the secondary terminals, this transformer is the culprit.

• Specs: 40VA rating | Primary: 120VAC | Secondary: 24VAC | OEM part number HT01CN241 | Matches factory wiring footprint and mounting bracket
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control circuitry. Undersized or off-tolerance generic units can cause nuisance tripping, blown fuses, or premature control board failure — this OEM unit eliminates that risk.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all low-voltage wiring before removal. Always check for a blown 3A or 5A fuse on the control board before replacing the transformer.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FX4DNF043000ABAA multi-position fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages on the data plate before ordering. Our HVAC parts specialists are available to confirm fitment prior to purchase — order with confidence and get your system back online today.