OEM Carrier 40VA Control Transformer for Model FB4CNF030010ABAA

This is the factory OEM replacement transformer (part HT01CN241) for the Carrier FB4CNF030010ABAA fan coil air handler. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, contactor, and all low-voltage control wiring. When this component fails, the entire control circuit loses power — your thermostat goes blank, the system won't respond to any calls for heating or cooling, and no diagnostic codes can even be generated. It is often the first component to inspect when a system appears completely dead despite confirmed line voltage at the unit.

• Specs: 40VA rating | Primary voltage: 120V | Secondary voltage: 24V | Direct OEM replacement for part number HT01CN241 | Factory-matched electrical tolerances
• OEM vs Generic: OEM transformers are wound and insulated to Carrier's exact specifications, ensuring stable 24V output under full load. Generic units frequently run outside voltage tolerance, causing nuisance lockouts, erratic thermostat behavior, and premature control board failure.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify zero voltage with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all low-voltage wiring connections before disconnecting. The transformer mounts to the blower compartment panel with two screws.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before cutoff ship the same business day from our climate-controlled warehouse.

Compatibility: Engineered specifically for the Carrier FB4CNF030010ABAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. If you have questions about fitment, our HVAC parts specialists confirm compatibility before your order is placed — no guesswork required.