OEM Carrier Control Transformer 40VA for Model FX4DNF037T00ABAA

This OEM replacement control transformer (part number HT01CN241) is the factory-specified unit for the Carrier FX4DNF037T00ABAA air handler. The transformer steps down line voltage from 120V to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coils, and control board. When this transformer fails, the entire control circuit goes dark: the thermostat goes blank, the system fails to respond to any call for heating or cooling, and nothing works. It is one of the first components to check when a unit is completely unresponsive despite confirmed line voltage at the unit.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM part number HT01CN241 | Factory-matched output for Carrier low-voltage control circuits
• OEM vs Generic: This is a genuine OEM Carrier transformer. Generic replacements may carry incorrect VA ratings or loose terminal fitment, risking control board damage or nuisance tripping of the secondary-side fuse. OEM ensures exact voltage output and physical fit.
• Install difficulty: 2/5 — Shut off all power to the air handler before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Verify 0V at primary terminals before touching wiring. Document all low-voltage wire connections before removal.
• Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Engineered as a direct OEM drop-in replacement for the Carrier FX4DNF037T00ABAA air handler. Always verify your existing transformer's VA rating and voltage on the unit's data plate or wiring diagram before ordering. Our parts specialists are available to confirm fitment — order with confidence and get your system back online today.