OEM Carrier Transformer 40VA 120V to 24V for Model FB4CNF030008ACAA

This OEM replacement transformer (part number HT01CN241) is the factory-specified control circuit transformer for the Carrier FB4CNF030008ACAA fan coil air handler. The transformer steps down 120V line voltage to the 24V signal voltage required to power the control board, thermostat circuit, and all low-voltage controls. When this transformer fails, the entire control circuit goes dead — the thermostat becomes unresponsive, the system won't call for heating or cooling, and no error codes will display because there's no power to generate them. It's one of the most overlooked causes of a completely unresponsive HVAC system.

• Specs: Input 120V AC | Output 24V AC | 40VA rated | OEM Part Number HT01CN241 | Factory-matched to Carrier FB4CNF030008ACAA air handler control circuit requirements
• OEM vs Generic: This is the genuine Carrier OEM transformer, wound to exact VA and voltage tolerances. Generic transformers often run under-rated VA, causing premature burnout when the control board draws peak current during startup sequences.
• Install Difficulty: 2/5 — Shut off all power to the unit at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Label or photograph all wire connections before removal. Two to four wire connections typical on the secondary side.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FB4CNF030008ACAA fan coil air handler. Always verify input voltage, output voltage, and VA rating against your unit's data plate and existing transformer label before ordering. If your thermostat is completely unresponsive and your breaker is not tripped, this transformer is the first component to test with a multimeter. Our parts specialists are available to confirm fitment before you order — reach out before purchasing if you have any questions.