OEM Carrier Transformer 40VA 120V to 24V for Model FV4CNF005T00AAAA

This is the factory OEM replacement transformer (part number HT01CN236) for the Carrier FV4CNF005T00AAAA fan coil air handler. The transformer steps down 120V line voltage to 24V AC, powering the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this part fails, the result is total system non-response: the thermostat goes blank, the system won't call for heating or cooling, and no control signals are sent to any component. It is one of the most overlooked failure points in any air handler diagnosis.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN236 | Factory-matched output for Carrier control circuits
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-tolerance generic units can cause nuisance tripping, control board damage, or intermittent thermostat dropouts — costing far more in downstream repairs.
• Install difficulty: 2/5 — Shut off power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label all low-voltage wiring before disconnecting. Verify 24V output with a multimeter after installation before restoring power to the full system.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our stocked warehouse.

Compatibility: Designed specifically for the Carrier FV4CNF005T00AAAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate or wiring diagram before ordering. Our parts team is available to confirm fitment — contact us before you order if you have any questions. In stock and ships today.