OEM Carrier Transformer 40VA 120V/24V for Model FC4BNB070000AGAA

This is the factory OEM replacement transformer (part number HT01CN236) for the Carrier FC4BNB070000AGAA fan coil air handler. The transformer steps down 120V line voltage to the 24V control circuit voltage required to power your thermostat, relay coils, and control board. When the transformer fails, the entire control circuit goes dead — your thermostat will go blank, the system will not respond to calls for heating or cooling, and no components will energize. A failed transformer is one of the most common causes of a completely unresponsive HVAC system.

• Specs: 40VA rated | 120V primary / 24V secondary | Class 2 transformer | OEM part number HT01CN236 | Factory-matched output tolerances for reliable control circuit operation
• OEM vs Generic: OEM transformers are wound and rated to Carrier's exact VA and voltage specifications, ensuring stable 24V output under full load. Undersized or off-brand transformers can droop under load, causing intermittent lockouts, nuisance tripping of the secondary fuse, and premature control board failure.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter, wire nuts or spade connectors. Photograph all wiring connections before disconnecting the old unit.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before cutoff ship same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FC4BNB070000AGAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the data plate before ordering to confirm fitment. Our parts specialists are available to verify compatibility before you buy — no guesswork required. In stock and ready to ship today.