OEM Carrier 40VA Control Circuit Transformer for Model FB4BNF018005AAAA

This OEM Carrier transformer (part number HT01CN241) is the factory-specified replacement for the FB4BNF018005AAAA fan coil air handler. The transformer steps line voltage (120V) down to 24V AC to power the low-voltage control circuit, including the thermostat, contactor coil, and control board. When it fails, the entire control circuit goes dead — your thermostat goes blank, the system won't respond to any calls for heating or cooling, and no components will energize. A failed transformer is often one of the first things to check when a system appears completely unresponsive.

• Specs: 40VA rating | 120V primary input | 24V secondary output | Factory OEM part number HT01CN241 | Direct plug-and-play replacement with original mounting footprint
• OEM vs Generic: The OEM HT01CN241 transformer is wound and insulated to Carrier's exact specifications, ensuring proper VA capacity and long-term thermal stability. Generic transformers may be undersized in VA rating, leading to overheating, nuisance tripping of the internal fuse, or premature failure that can damage downstream control boards.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all wire connections before removal. Verify 24V output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FB4BNF018005AAAA fan coil air handler. Always verify your existing transformer's primary/secondary voltage and VA rating on the unit's data plate before ordering. Our parts specialists are available to confirm fitment — reach out before you order if you have any questions. Order today and receive same-day shipping on in-stock parts.