OEM Carrier 40VA Control Transformer for Model FX4DNF049010ABAA Air Handler

This OEM replacement transformer (part# HT01CN241) is the factory-specified control circuit transformer for the Carrier FX4DNF049010ABAA fan coil air handler. The transformer steps line voltage (120V) down to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When this component fails, the entire control circuit goes dark: the thermostat goes blank, the system becomes completely unresponsive, and no heating or cooling calls can be executed. A failed transformer is often misdiagnosed as a bad control board, making this an important first-check component.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched OEM output tolerances | Part Number: HT01CN241
• OEM vs Generic: OEM transformers are wound to exact VA and voltage specifications for the Carrier FX4DNF049010ABAA. Undersized or off-tolerance generic units can overheat, blow fuses repeatedly, or deliver inconsistent 24V output that damages downstream components like control boards and contactors.
• Install difficulty: 2/5 — Shut off power at the breaker and disconnect switch before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to confirm 24V output post-install). Label all low-voltage wiring connections before disconnecting the old unit.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed and factory-matched for the Carrier FX4DNF049010ABAA fan coil air handler. Confirm your unit's existing transformer VA rating and primary voltage on the data plate or wiring diagram before ordering. If your system is blowing the transformer fuse repeatedly, inspect downstream wiring for shorts before installing the new unit. Have questions about fitment? Our HVAC parts specialists verify compatibility before every order — reach out before you buy.