OEM Carrier 40VA Control Transformer HT01CN241 for Model FB4CNP042L00AAAA

This OEM replacement transformer (part number HT01CN241) is the factory-specified control transformer for the Carrier FB4CNP042L00AAAA fan coil air handler. Its job is to step down line voltage (120V) to the 24V required by your thermostat, control board, and low-voltage control circuit. When this transformer fails, the entire control system goes dark — your thermostat loses power, the system won't respond to any commands, and nothing turns on. A failed transformer is often the first thing an HVAC technician checks when a system is completely unresponsive.

• Specs: 40VA rating | 120V primary input | 24V secondary output | Factory-matched windings and insulation class for Carrier air handlers
• OEM vs Generic: The OEM HT01CN241 transformer is wound to exact Carrier specifications, ensuring correct VA capacity and voltage regulation under load. Generic transformers are frequently undersized in VA rating, which causes overheating, tripped thermal fuses, and premature failure — especially when multiple 24V accessories (humidifiers, zone boards, dampers) share the circuit.
• Install difficulty: 2/5 — Disconnect power at the breaker before any work. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label or photograph all low-voltage wiring before disconnecting. Verify 24V output with a multimeter after installation before restoring the system.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier FB4CNP042L00AAAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate or wiring diagram before ordering. If you're unsure of fitment, our parts specialists are available to confirm compatibility before you buy — same-day shipping on all in-stock orders.