OEM Carrier 40VA Control Transformer for Model FX4DNF043T10ABAA Air Handler

This OEM control transformer (part# HT01CN241) is the factory-specified replacement for the Carrier FX4DNF043T10ABAA 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 transformer fails, the system goes completely silent: the thermostat goes dark, nothing responds, and no heating or cooling function is possible. A shorted transformer will often trip the system fuse repeatedly, making it a common misdiagnosed fault.

• Specs: 40VA rating | 120V primary / 24V secondary | Direct OEM replacement | Part number HT01CN241 | Matches factory wiring harness terminals
• OEM vs Generic: The OEM HT01CN241 transformer is wound to Carrier's exact VA and voltage tolerance specifications. Generic transformers frequently run at reduced VA capacity, causing nuisance fuse trips and premature failure under normal system load.
• Install Difficulty: 2/5 — Shut off all power at the breaker and air handler disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire stripper, multimeter. Confirm output voltage (24V AC) after installation before restoring full system power. Always check for shorted low-voltage wiring that may have caused the original transformer failure.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed and factory-matched for the Carrier FX4DNF043T10ABAA fan coil air handler. Verify your unit's data plate lists a 40VA, 120V/24V transformer before ordering. If you're unsure whether this is the correct part, our HVAC parts specialists are available to confirm fitment before you buy — just reach out before placing your order.