OEM Carrier Transformer 40VA 120V to 24V for Model FX4DNF043T10AAAA

This OEM replacement transformer (part number HT01CN241) is the factory-specified control circuit transformer for the Carrier FX4DNF043T10AAAA fan coil air handler. Its sole but critical job is to step line voltage (120V) down to 24V AC, powering the thermostat, control board, and every low-voltage relay in the system. When this transformer fails, absolutely nothing responds — the thermostat goes blank, the system will not heat or cool, and the air handler sits completely silent. A failed transformer is often misdiagnosed as a bad control board, making correct identification essential before spending more.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN241 | Factory-matched output tolerance for stable low-voltage circuit operation
• 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 of the fuse on the control board or premature board failure — use OEM to protect the entire system.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or terminal connectors. Verify output voltage (24V AC) with a multimeter after installation before restoring the system to operation.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our warehouse.

Compatibility: Designed for the Carrier FX4DNF043T10AAAA fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages against your unit's wiring diagram and data plate before ordering. If you need fitment confirmation, our HVAC parts specialists are available to verify compatibility before you buy.