OEM Carrier Transformer 40VA for Model FX4DNF037L00ABAA

This is the factory OEM replacement transformer (part# HT01CN241) for the Carrier FX4DNF037L00ABAA 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, absolutely nothing in the system responds: the thermostat goes dark, the air handler won't start, and no error codes appear because the control board itself has lost power. It is one of the first components to test when a unit shows zero activity.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched OEM part number HT01CN241 | Designed for Carrier FX4DNF037L00ABAA fan coil air handlers
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-tolerance generic transformers can cause erratic thermostat behavior, nuisance tripping of the 3A fuse, or premature control board failure — making OEM the smart long-term choice.
• Install difficulty: 2/5 — Shut off power at the breaker and verify with a non-contact voltage tester before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all low-voltage wiring connections before disconnecting. Swap wires one at a time to avoid miswiring the 24V secondary.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our climate-controlled warehouse.

Compatibility: Engineered specifically for the Carrier FX4DNF037L00ABAA fan coil air handler. Always verify the part number on the original transformer's label and confirm 120V primary / 24V secondary / 40VA rating on your unit's data plate before ordering. Our technical team is available to confirm fitment — just reach out before you buy. In stock and ready to ship today.