OEM Carrier 40VA Control Transformer HT01CN241 for Model FX4DNB043T00ABAA

This OEM control transformer (part number HT01CN241) is the factory-specified replacement for the Carrier FX4DNB043T00ABAA fan coil air handler. The transformer steps down line voltage from 120V to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, the entire control circuit goes dead: your thermostat goes blank, the system won't respond to any calls for heating or cooling, and nothing runs. It's often one of the first components to check when a system appears completely unresponsive.

• Specs: 40VA rated | Primary voltage: 120V AC | Secondary voltage: 24V AC | 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 rating and insulation class. Generic transformers may be under-rated for VA load, causing premature overheating and failure — especially in systems with multiple 24V accessories like humidistats or zone controllers.
• Install difficulty: 2/5 — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Always confirm 0V at the primary terminals before handling wiring. Photograph all connections before removing the old unit.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FX4DNB043T00ABAA fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. If you're unsure of fitment, our parts team is available to confirm compatibility before you buy — same-day shipping on all in-stock orders.