OEM Carrier 40VA Control Transformer HT01CN241 for Model FA4BNF018000AAAA

This OEM control transformer (part number HT01CN241) is the factory-specified replacement for the Carrier FA4BNF018000AAAA air handler. The transformer steps down line voltage from 120V to the 24V AC signal required to power your thermostat, control board, and all low-voltage components. When the transformer fails, the entire control circuit goes dead — your thermostat will go blank, the system won't respond to any calls for heating or cooling, and nothing will happen when you adjust the setpoint. This is often misdiagnosed as a bad thermostat or control board, so always verify transformer output with a multimeter before replacing more expensive components.

• Specs: 40VA rated | 120V primary / 24V secondary | Class 2 transformer | Factory OEM part number HT01CN241 | Direct plug-and-play replacement
• OEM vs Generic: The OEM HT01CN241 is wound to exact VA and voltage tolerances specified by Carrier engineering. Generic transformers often underrate true VA output, causing overheating under full control circuit load and premature failure — especially when multiple accessories (humidifiers, UV lights, zoning boards) share the 24V circuit.
• Install difficulty: 2/5 — Shut off all power to the air handler before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or quick-connect terminals. Photograph all wiring connections before disconnecting. Always check for a short in the 24V control wiring before installing the new transformer — a shorted low-voltage wire will blow the new unit immediately.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier FA4BNF018000AAAA fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages on the data plate before ordering. If you have added accessories to your 24V circuit, confirm total VA draw does not exceed 40VA. Our HVAC parts specialists are available to confirm fitment before you order — same-day shipping on all in-stock parts.