OEM Carrier 40VA Control Transformer HT01CN241 for Model FX4DNF025000ABAA

This is the factory OEM replacement transformer (part# HT01CN241) for the Carrier FX4DNF025000ABAA air handler. The transformer steps down 120V line voltage to 24V AC to power the low-voltage control circuit — including the thermostat, control board, and zone valves. When the transformer fails, the entire control circuit goes dead: the thermostat goes blank, the air handler won't respond to any calls for heating or cooling, and in some cases a tripped secondary fuse is the only clue. Replacing this part is one of the most cost-effective first steps when diagnosing a completely unresponsive HVAC system.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Hardwired leads | Factory-matched OEM dimensions and mounting footprint for direct drop-in fit
• OEM vs Generic: The OEM HT01CN241 transformer is wound to exact Carrier tolerances, ensuring stable 24V output under full control-circuit load. Generic transformers often deliver inconsistent voltage under load, causing intermittent lockouts or nuisance tripping of the secondary fuse.
• Install difficulty: 2/5 — Disconnect power at the breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all low-voltage wiring connections before disconnecting. Check and replace the 3A secondary fuse if the transformer failed due to a shorted wire — a new transformer will fail immediately if the short is not cleared first.
• Warranty: 1-year OEM factory warranty against defects. Orders placed by 3PM local time ship same business day from our climate-controlled warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier FX4DNF025000ABAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering. Our HVAC parts specialists are available to confirm fitment — contact us before you buy if you have any questions.