OEM Carrier 40VA Control Transformer for Model FX4DNF037000ABAA Air Handler

This is the factory OEM replacement transformer (part# HT01CN241) for the Carrier FX4DNF037000ABAA fan coil air handler. The transformer steps down 120V line voltage to 24V AC to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, absolutely nothing in your system will respond: the thermostat goes blank, the unit won't call for heating or cooling, and no safety outputs will function. A failed transformer is often misdiagnosed as a bad control board, making this an important first diagnostic step.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched OEM part number HT01CN241 | Designed for continuous-duty low-voltage control circuits
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control circuitry. Undersized or off-tolerance generic units can overheat, blow fuses repeatedly, or cause erratic thermostat behavior — costing more in callbacks than the price difference.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter (to verify 24V output after install), wire nuts or terminal connectors. Label or photograph all wiring prior to disconnecting the old unit.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships the same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier FX4DNF037000ABAA fan coil air handler. Always verify your existing transformer's primary/secondary voltage and VA rating against your unit's data plate before ordering. If your system has added accessories (humidifiers, UV lights, zone boards), confirm total VA load does not exceed 40VA. Our HVAC parts specialists are available to verify fitment before you order — don't guess on a control circuit component.