OEM Carrier Transformer 40VA 120V to 24V for Model FV4CNF005000ABAA

This is the OEM factory-replacement control circuit transformer (part number HT01CN236) for the Carrier FV4CNF005000ABAA fan coil air handler. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, and all low-voltage switching circuits. When the transformer fails, the entire control circuit goes dead — your thermostat goes blank, the system won't respond to calls for heating or cooling, and no error codes are generated because there's no power to produce them. It is one of the most commonly overlooked failure points in air handler diagnostics.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN236 | Factory-matched output tolerance for stable low-voltage operation
• OEM vs Generic: OEM transformers are wound and rated to exact factory specifications, ensuring proper VA headroom for all connected low-voltage devices. Undersized or off-tolerance generic transformers can cause nuisance tripping of the secondary fuse or erratic thermostat behavior, shortening the life of your control board.
• Install difficulty: 2/5 — Shut off all power to the air handler at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Always verify 0V at the primary terminals before touching wiring. Label all low-voltage leads before disconnecting.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Designed as the direct OEM replacement for the Carrier FV4CNF005000ABAA fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering to ensure an exact match. Our parts specialists are available to confirm fitment — order with confidence and get your system back online today.