OEM Carrier Transformer 40VA 120V to 24V for Model FY5BNF042L00AAAA

This is the factory OEM replacement transformer (part number HT01CN241) for the Carrier FY5BNF042L00AAAA fan coil unit. The transformer steps down line voltage from 120V to the 24V AC signal that powers your control board, thermostat, and all low-voltage components. When this transformer fails, the entire control circuit goes dark — your thermostat shows no response, the system won't call for heating or cooling, and the unit appears completely dead despite having power. A failed transformer is often misdiagnosed as a control board failure, so always test this component first with a multimeter before replacing more expensive parts.

• Specs: 40VA rated | 120V primary / 24V secondary | Factory OEM part number HT01CN241 | Direct drop-in replacement with matching mounting footprint and wire leads
• OEM vs Generic: The OEM HT01CN241 transformer is wound to exact VA and voltage tolerances required by the Carrier FY5BNF042L00AAAA control circuit. Generic transformers frequently run undersized VA ratings, causing thermal overload trips and premature failure — especially on systems with multiple 24V accessories such as zone boards or humidifiers.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdriver, multimeter, wire stripper, and wire nuts. Photograph existing wiring connections before disconnecting. Verify 24V output with a multimeter after install and before powering the full system.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FY5BNF042L00AAAA fan coil unit. Confirm your unit's data plate shows a 120V/24V, 40VA control transformer requirement before ordering. If you have questions about fitment, our HVAC parts specialists verify compatibility before every order — reach out before you buy.