OEM Carrier 40VA Transformer HT01CN241 for Model FX4DNF037010AAAA

This OEM control transformer is the factory-specified replacement for the Carrier FX4DNF037010AAAA air handler. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, contactor coils, and all low-voltage control components. When this part fails, the entire control circuit goes dead — your thermostat loses communication, and nothing in the system responds. If you have 120V at the air handler but zero 24V at the control board, a failed transformer is the most common culprit.

• Specs: 40VA rated | 120V primary / 24V secondary | OEM part number HT01CN241 | Direct factory replacement with matched impedance and thermal protection
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA and impedance specifications. Undersized or off-spec generic transformers can overload, trip their internal breaker repeatedly, or fail to power multiple zone valves simultaneously — especially problematic on multi-stage systems.
• Install difficulty: 2/5 — Shut off all power to the air handler before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label all wiring before disconnecting. Verify primary voltage with a meter before energizing the replacement unit.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier FX4DNF037010AAAA fan coil air handler. Confirm your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. Our fitment team is available to verify compatibility — don't guess on a control circuit component. Order today for same-day shipping.