OEM Carrier 40VA Control Transformer for Model FC4DNF042000AAAA (HT01CN241)

This is the factory OEM replacement transformer (part number HT01CN241) for the Carrier FC4DNF042000AAAA air handler. The transformer is the backbone of your system's 24V control circuit — it steps down 120V line voltage to the 24V signal voltage required by your thermostat, control board, contactor coil, and zone valves. When the transformer fails, the entire control circuit goes dead: your thermostat goes blank, the system will not respond to any call for heating or cooling, and no safety lockout codes are generated because the board itself has no power.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM part number HT01CN241 | Factory-matched to Carrier FC4DNF042000AAAA air handler control circuit requirements
• OEM vs Generic: OEM transformers are wound to exact VA tolerances for this unit. Undersized or generic transformers can overheat, blow internal fuses, or fail to sustain 24V under full relay load — leading to nuisance lockouts and premature control board failure.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label all wiring connections before removal. Verify 24V output with a multimeter before reinstalling the panel.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier FC4DNF042000AAAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering to ensure a proper fit. Have questions about fitment? Our HVAC parts specialists confirm compatibility before you buy — no guesswork.