OEM Carrier 40VA Control Transformer for Model FB4CNF042010ABAA

This is the factory OEM replacement control transformer (part# HT01CN241) for the Carrier FB4CNF042010ABAA fan coil air handler. The transformer steps down line voltage (120V) to 24V AC to power the entire low-voltage control circuit — including the thermostat, relay coils, and zone controls. When the transformer fails, nothing responds: the thermostat goes dark, relays won't energize, and the system is completely inoperative. A failed transformer is often caused by a shorted low-voltage wire or an overloaded control circuit, so always inspect the secondary circuit before installing the replacement.

• Specs: 40VA rated | 120V primary / 24V secondary | OEM part number HT01CN241 | Factory-matched construction for direct drop-in fitment
• OEM vs Generic: This OEM transformer is wound and rated to exact Carrier factory specifications. Generic replacements frequently run at reduced VA output, causing nuisance lockouts, relay chatter, or premature failure under full control-circuit load.
• Install difficulty: 2/5 — Shut off all power to the air handler at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Photograph all wiring before disconnecting. 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: Engineered specifically for the Carrier FB4CNF042010ABAA fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages 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 free same-day shipping on all in-stock parts.